You do, since you use hours, days, weeks, months, and years. It'd make more sense if an hour were 100 minutes, a day were 10 hours, a week were 10 days and a year were 10 weeks. Metric time does exist, but since we're all pretty much used to our weird system of measuring time, we just choose to stick with that.
Dave Holden yeah it is amazing how they pulled that one out their arse...I remember NTSC stood for never the same colour, SECAM Stood for system enitirely contrary to the American method, and PAL... peace at last....
I think they did the best to make the smooth transition from B&W to Color. If they changed the frequency or the amount of horizontal lines, it would make all B&W TV sets unusable, I guess. Some CRT expert here can comment for us!?
@@pangwa82 Yes, you are correct. If they changed any aspect of the existing waveform standard, they'd 'break' all existing TVs. Not only could they not change anything already working, but they had to *add* color to the existing standards, *without* it affecting B+W TVs. For those that don't know, the overlaid much higher frequency wave on top of the B+W wave. B+W TVs weren't affected by these newly added waves superimposed onto the B+W signal. The addition was a 'color burst' at the start of each line of horizontal B+W data, and then the color carrier was made to be out of phase with the color burst, and the 360˚ phase were assigned to colors! That is, at point A, the color wave is the same as the color burst, and so the TV shows red. At point B, the wave is 180˚ out of phase with red, and the TV shows red's opposite color, cyan. Meanwhile the amplitude of the original B+W wave is STILL telling the TV how *bright* to make that pixel. It's amazing what engineers accomplished without computers and modern electronics!
The BIG MYSTERY is why, despite: • The death of CRTs • The death of NTSC • The death of analogue broadcasting • The death of "standard definition" video • The introduction of 720p, 720i, 1080p, 1080i, 4K and 8K • The death of VCRs • The death of tape-based systems in video/TV production ...this ridiculous frame rate still exists. I beg EVERYONE in TV/video production, please ditch 29.97! It'd be exactly like a musician of today never recording a song over 4.5 minutes because otherwise it wouldn't fit on a 7" 45rpm single!
Limiting songs to 4.5 minutes constrains an entire art form. Having an awkward frame rate for your TV standard is a minor inconvenience to a tiny number of people. It's not "exactly like" it at all.
@@EebstertheGreat tbf how many songs are over 4.5 minutes. Only inconvenient to a small number of artists and barely any that would be played on the radio
@@EebstertheGreat I wouldn't say the entire TV industry* is a "tiny number of people". *I'm saying the entire TV industry, even though it's only America who uses these ludicrous frame rates because it's almost guaranteed that at some point, almost everyone working in TV will have to deal with some kind of video that originated in America.
@@tgktgkify It's not the entire TV industry who has to worry about the 0.1% difference in frame rate, just some techs in specific situations converting frame rates between formats. Everyone else involved (producers, actors, writers, cameramen, etc.) never have to think about it.
The huge irony is that NTSC does not have line by line phase reversal - aka Phase Alternating Line aka PAL. From memory the rest about adding the colourburst is correct, but that isnt, its the colourburst itself, it doesnt phase reverse. @Standupmaths - im kind of amazed you didnt mention even NASA would use the freq of the colourburst as a freq reference. I read a great anecdote where a TV station had their rubidium clock break down and had to return to an oven compensated xtal, and then was contacted by them asking what had happened to the signal and subsequently supplied with a ceasium clock for their colourburst :)
Next, can you do a video on why hotdog packages don’t match the number of buns in bun packages? I imagine it has something to do with the different resonate frequencies of the two foods.
Greg Belcher I figure the difference between the number of hot dogs in one package and the number of hot dog buns is because the companies that make them want you to buy more and if you buy 1 package of 10 dogs and one package of 8 buns, when they are all used, you have 2 left over dogs. If you want to use the last 2 dogs, then you might want to buy more buns, but then you would have 8 leftover dogs and the cycle of buying dogs and buns continues until you reach a common multiple of both dogs and buns, which is 40 dogs and 40 buns. For using even numbers of dogs and buns, there are no two better reasonable numbers for small packages of dogs and buns unless they are the same number, but the companies want to maximize their profits by keeping the customer buying dogs and buns.
The reason they don't match is due to the metric system. The companies making hot dogs readily took to metric's base 10 system while those baking buns stubbornly held onto the ridiculous imperial standards. No... I'm not being serious... why would you even ask that?
Something to note is that while NTSC is 525 lines, only 486 lines were actually used to visually show the image. The other 26 lines were used for vertical synchronization and retrace. Thats why SD digital is 480p, as thats equal to the actual visual representation of NTSC. PAL was about 600 lines of visible footage, so if you ever have on your hands a master tape of a European TV show, from BetaCam or something else, it makes more sense to up-convert it to 4:3 720p HD, or else you will be losing a bunch of quality.
Exactly, I rather over sample the video and get as much information from the picture as possible even if 720P or 1080i seems overkill. Analog video does have high frequency peaks and the professional analog recording equipment could capture a lot of information. Watching old Dr. Who episodes on blu-ray shows how good PAL video was, as far as the in studio recording elements were. The outside scenes were usually done with film, and those were re-transferred from original footage if available.
I have just spent too much time searching for my reference material! What I found was that 525/30 according to the NTSC spec, has a total 40 lines of blanking and thus 485 lines of active picture per frame. 625/25 according to the EBU spec has 52 lines of blanking and thus 573 lines of active picture. In practice this might vary, usually by rounding down. I did find two useful links. This one has a simple explanation of NTSC with some humour: www.sxlist.com/techref/io/video/ntsc.htm This one is more technical but has tables for everything, and links to more info than you would imagine: enacademic.com/dic.nsf/enwiki/14957 That one appears to be translated from German, so there are some quaint bits.
@@marcusdamberger Yes. BBC ALWAYS shot outdoors on 16MM film, and indoors in a TV studio on tape. You see this throughout the 1950 to around the 1990s, until decent tape-based recorders and cameras became cheaper than shooting processing and transferring film. Dr. Who is a great example, as is Monty Python
Yes, I did mean exposure, and white balance. He's wearing a white shirt next to a white monitor, that's glowing white. But the exposure was most affected, you're correct.
Early television engineers were damned smart. Make the best out of a crappy situation due to the limitations of physics and find a solution. And they did it by using their brains and education with good old pencil and paper. Hat off to them!
“PAL was better because it was higher resolution”. Not true. The reason was much more interesting. Colour information was coded in the phase of a sub carrier relative to a short burst of that subcarrier at the start of the line. The problem with NTSC was that the received signal could have phase errors due to things near the aerial blowing around in the wind. These phase errors would get turned into distracting colour (hue) errors. In PAL (Phase Alternate Line where the phase swung +/- 45 deg ) each tv line signal was stored in a delay line and averaged with the next line. The vector sum turned phase (hue) errors into amplitude (brightness) errors which were visually unnoticeable. That’s the real reason NTSC was mockingly called ‘Never the same colour’
I was at BBC Engineering Training Department Wood Norton in 1980 (a former stately home which doubled as UNIT Headquarters where Jon Pertwee first appeared as Doctor Who). Our lecturer, Pete Harris, had a humorous take on how the pros & cons of the three colour systems related to their names. NTSC was a beautiful work of genius but it suffered from one major problem - hue errors. (Thus American TVs all needed a 'Hue' control.) SECAM (Séquentiel Couleur À Mémoire) was fantastic for transmission (and protecting French manufacturing on the orders of Charles de Gaulle) but was mind-numbingly useless in the studio. PAL (Phase Alternating Line), however, took the otherwise excellent NTSC, built on the American experience and elegantly solved the hue problem. Thus, we had the three designations: NTSC: Never Twice Same Colour SECAM: Système Extraordinaire Contre les Américains PAL: Perfect At Last!
The wind did not cause hue errors in NTSC. The color subcarrier and the main carrier may shift together a little but, but, since the color subcarrier is detected as the difference between the carrier and the subcarrier (a much smaller figure than the main carrier), hue shifts did not occur. If the picture is heavily affected by dynamic multipath (e.g. trees blowing in a storm) can cause a loss in horizontal synchronization. When the back porch color pilot is freed from the synch, anything that occurs in the horizontal retrace becomes a false color reference.
@@1L6E6VHF That's not entirely correct. It's not a question of subcarrier and "main carrier". The colour information was sent on a subcarrier (a sine wave added to the video signal - 3.58MHz in NTSC and 4.433MHz in PAL). The instantaneous saturation & hue of the picture were given respectively by the amplitude of this wave and its phase angle with respect to a fixed reference. The angle of the fixed reference was communicated to the TV set by a short sample of about ten cycles of subcarrier at the beginning of each television line (the Colour Burst) and then maintained throughout the duration of the line by the BLO (Burst-Locked Oscillator) inside the TV.
Ah, 15,750 cps, I remember that number. The old "horizontal synch tone" I used to hear whenever the TV was on. My Dad declared I wasn't hearing it, of course what was really happening is *he* couldn't hear it.
Man, I remember that. That barely audible high-pitched whine... been so long since I've used CRT TVs or monitors that I'd forgotten about that. That's so nostalgic... I remember staying up all night watching Doctor Who on PBS on my little hand-me-down 13" black & white TV sitting next to my bed... wow. Now I want to go watch Doctor Who. lol
The video is pretty interesting but I must highlight that building up the presentation on that screen had to be a tedious job, so congratulations for all the time you and your team took for preparing the whole explanation!
Well Fahrenheit is used as a general sense of how hot something is. " It's 30 degrees? Oh that's cold. It's 100 degrees, 100 is a lot, so its really hot." Ask water how hot it feels and you get Celsius. Simplicity.
Horny Fruit Flies writes: ">29.97 fps >inches, feet, yards, miles >month/day/year >fahrenheit >handegg UNITED STATES OF MERICUH" Well, MERICUH is not how it's spelled, so that's not a valid complaint! (^_^) I thought the video explained why we have 29.97 fps. Bad luck, basically, and a desire to maintain backward compatibility. The numbers just happened to work out better in Europe. As for units, you use the right ones for the job (just like tools!). Feet are useful for high-energy physicists because light travels 1 ft. in 1 ns. So this is useful for estimating delays from cables. Month/day/year. You find day/month/year better? The best is really the ISO format: yyyy-mm-dd. And I wish the world would switch to that, but current date formats are like QWERTY: too deeply ingrained. I myself find writing m/d/y natural, just from growing up in America. Fahrenheit. I think this is more fitting for normal use. A Celsius degree is a little too large when used for indoor and outdoor temperature. Fahrenheit makes a weather map better, too. An area of 20's C would be too wide. Fahrenheit gives you "better resolution" while still working with integers. Scientists outside of the weather business typically use Kelvins and Celsius. You use the right units (tools) for the right job! Handegg? OK, I looked it up. To each his own. If you favor metric, or SI, units, I can tell you all sorts of non-metric or non-SI units that are used by scientists: atmospheres, G-forces, parsecs, feet (already mentioned), hell, let me just quote an old post of mine from another website: "Speaking of units, scientists frequently use non-metric units: light-year, parsec, astronomical unit (equal to the radius of the earth's orbit), (an) atmosphere (a unit of pressure, though more for convenience when precision is not paramount), G forces, electron volt, barn (a barn is 10^(-24) cm^2), fermi (which is 10^(-13) cm). These last two are based on a metric unit, but so is the inch (defined as 2.54 cm), so it's just as "bad", sort of). The electrical charge of particles, in many cases, is more conveniently measured in multiples of that of a proton, as in the charge on an electron (which would be -1), or quarks, which, depending on which quark you're dealing with, is +/- 1/3 or +/- 2/3 of that amount of charge. There's also a foot (of cable, or patch cord, if you will), which is how far light and electricity) travel in one nanosecond. This is useful in high-energy physics experiments for estimating delays. I believe calories are still used by some, though I'm not really sure. Add to all this units of time: years, months, weeks, and days are not metric units, yet scientists use days and years, at least. The dinosaurs were wiped out 65,000,000 years ago. No one converts that to seconds. Angstroms are still used (based on a metric unit, though). There are probably more. Bottom line: Use the units that are appropriate for the job."
I never got the argument that Fahrenheit gives you better resolution. Why would you ever need slightly better resolution for Temperature, and if you do: Why not use the Celsius value with another digit? Also, the estimate that light travels 1 feet per ns is just that; an estimate. The estimate has an error of about 1.7 %. Pretty sure mostly American or English engineers use it, and for any serious calculations you'd use meters. We use the units we're used to. It's an important part of our culture.
To be precise, for NTSC 4.5 MHz is the frequency difference between the video carrier and the audio carrier for each (6-MHz) channel. IIRC, the reason that this value could not be changed (leading to the math discussed by Matt) was that if you moved the audio carrier (say to keep 30 frames per second with 525 lines per frame as well as the half-integer requirements), the audio demodulators of the existing B&W TVs would be unable to correctly demodulate the audio. Analog TV audio for NTSC was frequency-modulated (as well as pre-distorted, but that’s a topic for another discussion), and I believe that the analog circuitry used at the time could not tolerate much error in the location of the audio carrier. The video demodulation, on the other hand, could tolerate a much larger relative change without needing redesign (say 30 Hz to 29.97 Hz, or around 1%).
I'm not sure where you got this from but it contradicts what the main problem the standard was trying to eliminate. The new subcarrier (3.583125 MHz, for color) had harmonics that interfered with the FM sound subcarrier (4.5 MHz) creating a constant buzz in the audio. By lowering the framerate along with the SC frequency the noise in the audio was reduced (beat frequency was now outside the audio bandwidth) and everyone signed off. Lots of compromises b/c no one wanted to reinvent the wheel with the color SC again.
@@Anonymous-df8itInteresting proposition. For example, the integer multiple could have been reduced to, say, 280; with 525 scanlines at 30 Hz, this would bring the bandwidth down to 4.41 MHz.* * _4.41 MHz is a square number, if that livens things up at all..._
Growing up in this digital age, where FPS is usually expressed as an integer, I never knew why my video editing software always defaulted to such a specific decimal value. The answer was much more fascinating than I expected. Thanks for the info!
Nice. I remember changing my DVD player output from PAL to NTSC, and see the screen blink, colours go haywire and picture area shortened vertically. This video explains it clearly.
That's a good explanation except for fact that it's not 100% technically accurate. 29.97fps * 525 lines * 286 is actually equal to 4,499,995.5. Although we nominally refer to the NTSC framerate as 29.97, that's actually just an aproximation. The true framerate is actually 30/1.001, or about 29.97002997002997... When you plug 30/1.001 into your equation, you get EXACTLY 4,500,000Hz.
It's nice explanation but based on wrong facts. PAL channel is wide enough that you don't need to mess with Δ2 = ODD2 * fh/2. Sound use FM modulation, so there is no way to interlace sound spectrum and chroma spectrum, so exact Δ2 doesn't help much. In Europe we have 5,5MHz, 6,0MHz and 6,5MHz sound IF (Δ2 is different) and all systems use the same PAL 4,43MHz frequency. PAL creator Walter Bruch choose chroma frequency other way - PAL use the same horizontal (15625 Hz) and vertical (50Hz) frequency like B/W standard, but chroma frequency was shifted - fv/2 was added to minimize artefacts. In fact in PAL it must be ODD * fh/4 (because of PAL phase alternating line by line) + fv/2. Exactly: 1135 * (15625Hz/4) + (50Hz/2) = 4,43361875MHz So PAL never used chroma frequency ODD * fh/2 ! It was only used in experiments with NTSC based system in Europe in early 60's.
+xsc1000 The explanation is specifically pertaining to the North American NTSC standard. PAL was developed after NTSC so the engineers were able to avoid many of the inherent flaws that plagued us here in the USA.
You count 6MHz bandwith for PAL for Δ2, but in fact it is 5,5MHz in original German version, 6MHz in British version and 6,5MHz in eastern Europe version. If NTSC changed horizontal lines to 625 (like you offer), none of B/W set would be compatible because of horizontal oscillator changed frequency. Also horizontal resolution would be low. You can count bandwith you need for Y (luma) signal by this equation: B= 625 (horizontal lines) * 625 * 4/3 (vertical lines) * 30 (framerate) /2 (two pixels create sine wave period) = 7,8MHz. But you have < 3.5 MHz for luma in NTSC, so horizontal resolution would be less than half the vertical resolution.
From what I remember from working in broadcast TV, the reason they stuck with this as a standard was for backwards compatibility. They wanted to still be able to broadcast the same signal so it works on the millions of black and white TVs that were already sold to consumers, and to enable TV stations who invested millions to not have to scrap everything and start over.
I am telecommunications engineer and I never had so good explanation of the whole thing like you did right there in this video. Not to mention how entertaining it was. And a good hearted joke from my side... I learned in school that NTSC stands for 'Never The Same Color' and PAL stands for 'Perfect At Last' ;)
@@bobweiss8682 System Entirely Contrary to the American Method. I used to know how to write this in French, but can't find the note I wrote back in the late 70s!
look right at the end when the Patrion logo is on the CRT you can see a black stripe slowly edging downwards - a mismatch between 29.97 and 30, Close enough to be usabe
When I worked in a post production house in Hollywood, the saying was: NTSC = Never The Same Color Also, in order for timecode on broadcast videotapes to make sense with the 29.97 framerate, they developed "drop-frame timecode," typically denoted with a semicolon or period after the seconds [HH:MM:SS;FF]. For every minute not ending in a zero, two frames were skipped in the timecode. If they hadn't done this, then every hour of timecode would have an additional 3.6 seconds of real time.
Yeah, I've researched this because why not-yeah, "because why not" is why I research most of the things that I do. So 00:00;00 is a real timecode, as are 00:00;01, 10:00;00, and 10:00;01, but 01:00;00 just doesn't exist, and neither does 01:00;01, or 01:00;02 or 01:00;03 in the case of 59.94fps. This drops 18 frames (29.97fps) or 36 frames (59.94fps) every 10 minutes (18000 frames in 30fps or 36000 frames in 60fps), leading to a frame rate of 17982 or 35964 frames per 10 minutes, or 29.97 or 59.94 exactly. NTSC is actually 29.970029 970029 97... frames per second, which means that timecodes with the SMPTE drop-frame correction still drop a frame every few hours.
Who on earth is going to notice the extra 3.6 seconds of real time? Also, you still end up with the problem that every hour of timecode is short 3.6 milliseconds of real time (4500000/(525*286) isn't exactly 29.97)
@@Anonymous-df8it We're talking about TV networks who sold advertising space by the second, so they needed to be precise in how everything was measured. Also editors would often have to deal with audio coming from different sources, so having the sync drift by 3.6 seconds per hour would be catastrophic. Those are just two of many reasons why precise timecode was important.
The whole point of NTSC color tv was to put in a standard in which people who still owned black and white sets (vast majority) could still see color broadcasts and color tvs could still see black and white broadcasts, this was referred to as "compatable color". If they were to have adjusted the horizontal lines like you suggest the would have made a signal that no tv could display, therefore defeating the whole point of their efforts. In Europe, when PAL was introduced, anyone still using the old 405 line black and white sets, just didnt get to see the new color shows and anyone who had a color tv couldnt see the old programs.
All color TV Systems (NTSC, PAL, SECAM) had to be backwards compatible to black and white TV standard. It would have been too costly to broadcast the same content simultaneously with two different standards. At introduction of color TV most pople still had b/w TV sets and only a few shows were actually transmitted in color.
@@oldSwede65 Also most of Europe were broadcasting 625/50 before they started broadcasting in colour! There was overlap with 405/50 staying on for some years until all the old VHF transmitters were replaced by UHF. The programmes they broadcast were the same, just in B&W. The BBC made everything in colour 625/50, and there were standards converters at TV Centre to down-convert to 405. I the French even had some 819/50 B&W transmissions running after they converted to 625.
@@oldSwede65 And yet, the UK did exactly that for nearly 20 years (if you count the Trade Test Transmissions on BBC 2, which, though illegal to watch, were being seen nonetheless, as the law was virtually unenforceable).
Ummm, the current definition of the second was the result of a collaboration between the British National Physics Laboratory (NPL) and the United States Naval Observatory in the late 1950's. (You might be able to guess the nationalities of those two institutions.) The effort was aimed at defining the atomic (silicon) second to match as nearly as possible the 1898 definition of the ephemeris second, as given by Simon Newcomb, Newfoundland born director of the United States Naval Observatory, employing the lunar theory of British born Yale professor Ernest William Brown. The modern second is pretty much an Anglo-American project.
On youTube (and especially numberphile) one can never be certain. I guess I took nationalistic umbrage, given that the definition of the second, at least since the late 19th Century has been pretty much a U.S. project, with substantial help from the UK's NPL. I suppose you're going to tell me that we're nitwits for not using a rational and sane AC frequency like 50 Hz, or a "more efficient" mains voltage like 220V.
As a curiosity, Brazil used a NTSC-PAL hybrid called PAL-M, which featured 525 lines, exact 30 fps, and the PAL color encoding scheme with almost the same chroma carrier frequency as NTSC.
Yes very similar but being PAL there had to be a quarter-line offset so the frequency changed. Another difference between PAL-M and European PAL is that there in no 30Hz subcarrier offset (25Hz is used in Europe). This offset was an afterthought by Dr Bruch and has caused us heartache in Europe with editing.
Kind of an odd fact but Super Smash Bros Melee on the gamecube is primarily played on CRT tvs because there is less lag. In fact watch any ametur to professional SSBM match and they are playing on CRT tvs. They are in very high demand right now among the Melee community as good ones are becoming harder to find
Great video, and very informative. I have long wondered but never bothered to check. (Phase reversal requires that the phase of the wavefunction describing the signal be adjusted by precisely one half of a wavelength for each color frame, hence the need for an integer multiple.)
They did not just take 60 Hz to match the electricity outlet, since synchronization could be set to anything, they did it to avoid interference-flicker with studio lamps and lights that are also connected to 60 Hz outlets.
I'm pretty sure that most TVs had their electron beam deflected by the environmental 60Hz electromagnetic noise, this would cause the screen to move vertically at the beat frequency between 60Hz and vertical scan rate. That would be quite annoying though I'm guessing 29.97 is close enough that a movement that takes 30 seconds to complete would not be noticeable.
@@CSGhostAnimation - Yes, Thomas Edison's plan of transmitting power as DC instead of AC would solve the problem. It would also create far bigger problems. The problem is the current that's not inside your TV set. It creates a magnetic field that deflects the CRT electron beam. The frequency difference between the external magnetic field and the vertical scan rate is what you see as motion on the tube.
Unfortunately, changing the number of horizontal lines in a North American TV picture from 525 to 625 would have destroyed backwards compatibility with the existing black and white sets.
Not really, vintage tv´s had vertical, width, horizontal controls to ajust the picture on the tube It was more easy to implement.back in those days. I remember a guy in Portugal receiving by sky skip a freak signal of Brazilian tv that came in,and all he did was ajust his 625 50hz tv to 525 line 60hz on a small portable black and white set. using the vertical width controls Brazil does use PAL but on 525 60hz But the tv been an old b/w did not have to deal with other things of the signal. The video is on youtube
@@angelsmith1761 You are assuming that existing TV's had horizontal and vertical frequency controls that would have sufficient range to make such large frequency adjustments and that the circuits would still have performed properly with such a large deviation from what they were originally designed to work at.
Jackson Kennedy different dialects spell things differently. Believe it or not, Europeans spell some things very different than originally intended. Just like Americans
Also changing the number of lines in the signal would completely brick the older TVs, introducing an odd, skewed horizontal rollover as the greater number of horizontal lines would cram the same number of pixels into less horizontal space.
A small change to the number of lines would not have caused any particular difficulty with consumer video equipment. Until the late 1990s, most video game systems output video that was significantly different from what the NTSC specified, but TV mostly coped with it just fine.
Yes, a lot of early gaming and home computer systems produced signals that were more than a bit off, but the NTSC engineers were tasked with creating a standard that would be least disruptive and compatible with older B&W sets. Changing the vertical scan rate by a tenth of a percent was very likely to work on all receivers; changing the number of horizontal lines by 20% would have produced the artifacts seen with many games & computers, like jittery pictures, tearing, and flag waving. I don't believe any of the European color standards were compatible with their earlier B&W signal. They saw the compromises the NTSC engineers made and decided to just abandon the old standard and start over for a better color picture, also a reasonable engineering decision, but it forced customers to replace their sets.
All the European colour standards were fully compatible/transparent and usable on older B&W TVs. No sets needed to be replaced (until digital broadcasts came about, but that was much more recent).
If someone is more informed than me, please feel free to correct me, but I believe that the 60FPS (and 50 for PAL) is only the first round of scanning (meaning half the scanlines). When you combine the two different scans in order to have a "full image", it totals to 30FPS. So, 60FPS for one out of two scan cycles, 30FPS for two out of two scan cycles.
Karolos Triantafyllou Sorry, no. The "frame" as described by NTSC/ATSC or other interlaced formats is actually a combination of two different images (these are called fields). NTSC has 59.94 distinct images (fields) per second. The 30 frames per second idea a very bad naming scheme.
The lowest common multiple of PAL 50hz and movies 24hz is 600hz The lowest common multiple of 60hz and 24hz is 120hz. Sorry, PAL doesn't have enough prime factors in common with cinema for my taste.
Patrick Wise You're forgetting that as explained in the video, NTSC is actually 29.97 FPS an not 30/60. The lowest common multiple of 24 and 29.97 is 23976. Checkmate :^)
although what's funny about this, is that on UK TV, films, shot at 24fps aren't "mapped" (3:2 Pulldown i believe it's called) like on the NTSC system, we simply show 24fps at 25 fps. This is why if you check running times of movies shown on UK television it is about 4% shorter than the actual running time. Also, now we are in the age of 1080P and soon 2160 P or even higher, why are we still having to even think about drop frames and 29.97 frame rates?
Actually, NTSC stands for Never The Same Color, since color hue was based on that signal phase shift, which was EXTREMELY fiddly, and prone to all kinds of error, since it depended on the signal oscillations following a rigorous phase timing, which could shift with factors such as length of cables in a studio. In fact, those famous color bars were created as a way of calibrating the color as closely as possible with the naked eye. Fun stuff. The mechanics of an NTSC signal "frame" is pretty fascinating! It sucks by today's digital standards, but for what they had at the time, those engineers came up with some creative ways of packing information into a signal!
You have the "cause" and the "effect" backwards! The NTSC color subcarrier was 3.579545MHz which was the closest "easy to manufacture" crystal that would get close. But the oscillator needed to stay in phase from the end of one video frame to the start of the next or else the color would drift. The shortened frame rate was to keep the "ScH Phase" (sub-carrier to horizontal) correct. You work that backwards to get the numbers in your presentation! The ACTUAL frame rate is in fact 30 x (1000 / 1001) and you need about five digits of precision. 30 x (1000 1001) comes to 29.97002997 … but notice that there are two trailing zeros after the 29.97 which is the only reason why it's "close enough". But you are absolutely correct - dealing with non-integer frame rates (and interlaced video in general) have been the bane of the broadcast engineering community for decades!
There were several attempts at coming up with a color standard. Finally, it was realized that with the expense at the time of television in general--and especially the new color sets--you would have to make it "backwards compatible" to the existing B&W sets or you would be selling zero color TV sets and would fail. So they did, and made the best of a bad situation. PAL is superior in many respects--and is so because it started from scratch with the lessons learned by the compromises that had to be made in the North American system. Had that been a real option for the American engineers, they would have loved to start over and make a clean solution. But marketing always asks for miracles, and it's up to engineering to deliver them (compromised as they may be).
Have to add that at the time devices were meant to last forever. You could not simply ditch a B&W set because it's outdated due to a standard of color tv being introduced. Of course things have changed...
@@PR-fk5yb In the 1950s TVs were far more expensive relative to average earnings than they are now. Colour sets even more so. Although NTSC colour transmissions started in 1955 it wasn't until about a decade later that colour TVs outnumbered B&W ones in US homes.
@@zoewells3160 lol remember that story : What if Microsoft had invented the automobile? It would not work certain types of gas or it would suddenly stop on the highway for no reason then you would have to find the stop button in order to restart it... If Apple had invented the television... you would have to pay $$$ just to use the airwaves or you would have to pay an extra everytime you would change the channel...
Wonderful explanation, and the “beam graphics” demonstrated on your CRT really clarifies how the sweep, scan, and interlace produce the raster. It’s amazing how these vestigial technologies spill over to complicate modern methods...
The total time of a frame is enough to draw 525 lines on the screen, but that assumes you are dividing the frame time by the time to draw one horizontal scan line. However you have to also include the horizontal blank interval i.e. the time the beam is off so it can be repositioned at the start of the next scan line, as well as the vertical blank interval, i.e. the time the beam is off so it can be brought back to the top left corner of the picture from the bottom right and does this for each half frame. When those are taken into account, it turns out you only get 480 scan lines total. Horizontally, you can draw 320-350 alternating dark and light vertical lines giving you (in computer monitor terms) about 640-700 pixels on each scanline depending on how good your comb filters are. I know, 4 years late to the party, but there it is.
Wrong, increasing NTSC to 625lines would have been a mistake. The goal for adding colour to the signal was to retain compatibility of all broadcasts with all sets, regardless of whether a black and white set or a colour set was receiving either an old black and white or a new colour broadcast. That fancy 15734 number is actually the operating frequency of the horizontal oscillator 15.734KHz which is what causes that farmilar high pitched buzz we hear from the back of an operating set. increasing the number of scan lines would dramatically increase the frequency outside the resonance and tolerance of the oscillator circuitry. This oscillator is local and is timed using sync pulses in the video signal. A 100 line increase would ad 2KHz to the horizontal oscillator and could make it become unstable, not to mention the horizontal oscillator not only draws the raster but also provides the HT for the cathode ray tube through the flyback transformer, which is a central part of the oscillator. the flyback is designed to resonate at the 15.734KHz horizontal frequency for efficiency. If the oscillator becomes unstable you could end up with timing issues and complete loss of HT to the tube if the oscillator collapses, and also the potential for burning up the drive circuitry for the HT supply, since it was all designed to resonate at the horizontal frequency. Sets would struggle and cheap ones would outright fail. It would require modifying the set, or replacing it entirely which is exactly what they were trying to prevent, remember back then a television was not a small investment.
NTSC was a major breakthrough to add color to B & W in the same bandwidth and maintaining compatibility. PAL suffered major problems with flicker. The reason movies could get away with 48 Hz without major issues with flicker was that they were viewed in a dark room, and PAL needed to also be viewed in a low light environment. NTSC at 60 Hz can be viewed in a more normal lighting, but still had issues in daylight. To get beyond flicker, the refresh rate needs to be >75 Hz. I worked in TV/video from 1977 to 2007, at 66yr I am still able to hear and be annoyed by 15,750 Hz.
They could not have made 30 x 625. That would have brought the horizontal frequency to 18750Hz, which is quite a leap from 15750. It would have broken compatibility with existing sets and other equipment. The change from 15750 to ~15734 worked because the analog electronics involved had some, say, "give". They could tolerate some variance up and down from the expected frequencies, but that much of a change would have been tolerated by very few existing sets, if any at all. Also, even for those sets that would tolerate and display the new signal, most would probably suffer from some instability, and even those that were stable, would need to be serviced to get the new signal to display correctly, because the video signal doesn't contain driving signals for the deflection coils, but just pulses signaling when to return to the starting position to scan a new line or frame. Then, the electronics on the TV set, upon detecing that pulse, internally generate the sawtooth electric currents that actually drive the deflection coils. These are called flyback transformers. Those found on PC monitors with geometry controls can be adjusted pretty widely, but those on regular TV sets are specifically made for one and only one sawtooth wave lenght, which determines line lenght on the screen. Basically, your +18kHz horizontal sync signal, if accepted at all by an existing TV set not specifically made for it (let's rememeber that the idea was to keep compatibility with older BW sets), would result in a picture that didn't fill the whole screen but left a portion of the right side of the screen completely black, because a new horizontal pulse would arrive before the flyback transformer could have driven the electron beam all the way to the right side of the screen.
@@jeepien Have you tried it with TV equipment of the time? I'm not saying I did, but it sounds like, if it was as easy as that, they would have done it, right? So, are you sure it would work?
@@radornkeldam No, I haven''t. Although it would in principle, it's quite likely that such a large change would push it outside the range of existing controls. Nothing is easy. I did have TV equipment back when the NTSC change occurred, and it was completely undetectable on older B&W TV sets. The Vert and Horiz controls needed occasional adjustment anyway, and had no calibration of any kind, so any small change would not be noticed. You just turned the knobs till the picture held still.
@@jeepien Many - if not most - TVs back then used as adjustable coil in like with the yoke to change the width. And they didn't have a whole bunch of adjustment. They also didn't have a horizontal phase adjustment. You could adjust the centering magnets on the tube to some extent.
@@compu85 TV sets had "Horizontal hold" and "Vertical hold" controls. Just knobs, no numbers. You would adjust the horizontal until the picture stopped looking like a bunch of slanted lines and torn up garbage. You would adjust the vertical hold until the picture stopped rolling frames and locked on one stable frame. Once you got it close, the frequencies would lock to the sync pulses in the picture data, and everything would remain stable. A tiny difference between 30 and 29.97 would not be detectable by anyone with an analog TV set. On the back of the set, through screwdriver sized holes, you would find rarely needed adjustments of Width Vertical position, and Vertical linearity. These were local adjustments unrelated to the signal. They just put the picture in the right place on the screen, and didn't need to change to match the signal.
With colour TV the subcarrier frequency is the reference for line and field frequencies. This is to minimise sub carrier visibility in the way you mention. In generating the sub carrier, the engineers wanted to use simple multiples of an integer reference frequency (a whole number of MHz) and try to get as close as possible to the existing line and field frequencies. The choice dictates the exact line and field frequencies, and they tried to choose a reference and multiples/divisors to get as close to the existing freqs as possible, and settled on 5×7×9/(8×11) MHz. The frequencies are not tightly locked to the 4.5 MHz video bandwidth, there is no need to control this tightly. The development of NTSC was utter genius and was pushing technology beyond known limits.
Excellent history lesson! As a former resident under NTSC, and also wondering how in the world 29.97 ever existed, I found your video very interesting and exciting! I'm exploring the possibilities of video production and editing in post. Thanks. RS.
If they had chosen to increase the line count to 625 instead, then the spectrum of the signal would have changed, adding more high frequencies, making it no longer fit into that 4.5 MHz window.
Perhaps. But the main reason for keeping 525, as many others have already noted here, is because most of the TVs out there were B&W (and there were lots and lots of them), and they could not adopt a standard that suddenly made everyone's TV become useless.
It could have been fitted into that window, but it would have required more aggressive low-pass filtering, which would have resulted in a blurrier picture.
Televisions of the early 1950s were really, REALLY forgiving as far as what they would accept as input. They all had H-hold and V-hold knobs that changed the timing of the signal. Even later TVs with only the V-hold could somewhat display 625 lines by adjusting the V-hold knob. A 1950s TV could very easily be adjusted to display 625 lines, without losing any of the picture. The biggest problem would've been that 625 lines would be quite blurry on American TVs. It would still have to fit into the same 6 MHz channel space that was originally designed for 441 lines in the 1930s.
I'm sure the people working on the standard would have used 625 lines if they knew for a fact that all existing TV's could handle it (even if they needed adjustment). The fact that they didn't shows that it wouldn't have worked. Perhaps because it'd be blurry, but I don't see all TV's being that forgiving. Remember that "most TV's will handle it" isn't good enough, you must guarantee that all will.
Another constraint on NTSC television was that the color signal had to be viewable on black and white TVs, which were the vast majority of receivers in use at the time. So they could not change the number of lines. Changing the frame rate by 0.1% was within the tolerance of what the existing receivers could accept. So it wasn't a bad choice, it was a very clever choice that met all constraints. Far from dumping on the engineers of the 40s and 50s, I admire their ingenuity. Modern digital techniques are much easier and far less constrained by physical and mathematical laws.
Sadly this is one of the problems being early when adopting new technologies. It can be difficult to tell exactly what you need, how to create something, and so on. This often ends up in you finding out what you should have changed. But, by then the old systems are already in place and you can't just shut them all off.
How is that sadly in this case? Whoever decided that near-30 fps is enough made a tech that lasted 40-ish years and near no one ever said it's a problem or even acknowledged. On the other hand now we have opened pandora's box where most people are moving toward 60fps while at the same time there are already people who say 90 or 120 or 140+ is the minimum desired level. Leading to tech being deprecated often within a year while we are supposed to save resources and environment.
@@kallemetsahalme5701these are 2 very different things. It isnt exactly the fps that is the problem, but having to be compatible with b&w and make a smooth transition. It is about getting the technology and not fully understanding it and planning it out that leads to problems. Luckily with tv it is just a debate, but with other things it has costed lives.
@@kallemetsahalme5701 Your point is 100% correct. However, in this case it was a decision of backwards compatibility AND seamless change. Nothing really about frame rate itself. As no one will notice the -0.03 Also are people saying that like 90, 120, 144, etc. is the minimum desirable frame rate? As I will be honest 60fps is perfectly fine, 120 fps is even better, and 240 fps is incredible. It depends on application though. Gaming? 120 and above Watching movies? 30 or 60 Animation? 30 is probably the best
The problem with 25 fps is that it flickers like hell, specially in CRT monitors. It was impossible not to notice it back then. Curiously enough, Telefunken developed the PAL-M back in the 70s. It has 60fps (not 59.97) and also features the phase alternating line (aka PAL) that made the European PAL famous for its color fidelity. The system was only adopted by Brazil and worked pretty well.
To be fair, most European TVs would have compensated this flickering issue by using phosphors with more persistence (the glow lasts longer). The problem with this, however, is that you would notice the persistent glow a lot more if you were watching a content with high contrast--for example, a helicopter searchlight beaming down from a dark sky, well, you'd notice a trail of glowing phosphors behind the searchlight a lot more with a PAL TV. As for PC monitors though, the phosphors had even less persistence than an average TV, because they were generally supposed to be run at 70 Hz or higher. That's why running one of those at 50 Hz is just eye hurting!
I don't know of any theatre that uses CRT projectors or old-school film projectors anymore--at least around where I live--so I'm not sure if that's a big issue anymore since it seems the most common projection tech is based on displays that don't inherently flicker. I can't really say I've ever noticed a 48 fps flicker on a recent movie night.
Even older movies didn't scan so their was no flicker. Fps in the theater is the whole frame at once. You only have 1 line between frames that interrupts the image. You don't have half of the image being scanned in at once then the other half.
No, that's not right. You cannot show a frame in theatres for a complete 1/24th second, because the film stock had to be pulled in place and then advanced to the next frame. The film transport would cause immense vertical motion blur (for regular 35mm projection). Theatres always used rotating shutters to hide the film transport motion. That was also done with the cameras. To make this rotation smooth, each of the 24 frames was interrupted twice. During one of the interruptions the frame was transported. This resulted in 48Hz for 24 frames :) Later projectors used higher speeds, such as 72Hz or 96Hz (probably why nobody noticed flickering in the last decades).
I screamed when I started to watch this the first time. I'm older and less prone to screaming over tiny details.... I did write up some number details you seem to have glossed over. The numbers were not changed to the "obvious" numbers for backwards compatibility, a concept digital TV blew out of the water. There is a very obvious question here, why was the sound subcarrier frequency not modified by 0.01% to 4.50450450450 MHz? That's a story about available electronics parts of the era. Precision frequency sources were all generally multiples of 5 MHz. 4.5 MHz is fairly simple to generate from 5 MHz. From there you need to use clumsy parts to synthesize the various frequencies used in the signal. To totally unwarrranted levels of precision 5 MHz 63/88 = 3.57954545454545454 MHz, color subcarrier. Color subcarrier times 4 = 14.31818181818 MHz. The video was presumed to give 910 pixel times per line 720 of which were visible and the other intervals were part of a complex synchronization process. 14.31818181818MHz / 455 = 2 * 15734.265734265734265734265734266 Hz Then there are a total of 525 line times, some 45 of which are for special services, retrace, and synchronization signals. Roughly speaking, though, only about 400 or fewer are usually seen on TVs. 15734.265734265734265734265734266 Hz / 525 = 29.97002997002997002997002997003 Hz or about 1 part per million off 29.97 Hz. In practice banks of dividers off either 14.3181818+ MHz or 28.6363636+ MHz derived from 5.0 MHz oscillators were used for a long time. In the Los Angeles area the 5 MHz oscillators were often derived from cesium frequency standards before people realized they didn't really have to be super accurate after all. If everything was moved to 60 Hz all that nice arithmetic right up at the start goes to "heck". And they didn't really want to use more difficult frequency generation techniques. After all, WWV transmits at 5.0 MHz not 4.995 MHz. And the FCC had demanded precision at first. {^_^}
Changing NTSC to 625 lines would have helped PAL video gamers. We got a raw deal until about 1999-2000 when PAL 60Hz games started appearing. PAL games at 50Hz always ran slower and with borders because developers didn't use the extra 100 lines and the games were rarely adjusted for speed at the lower frame rate.
First timer here at your channel and love how you explained it (very clearl) and the exactly timed animations on the CRT. Well done! This is an excellent example that a (minimal looking) video like this can be informative, fun to watch without the need of fancy stuff around. Really like it.
Yeah, NTSC is "not the smartest choice," except for the fact that Americans, in essence, INVENTED broadcast television. Yeah, B&W NTSC was finalized in 1941, and NTSC color in 1953, while PAL was finalized in 1962. When NTSC was first invented, nobody had even thought about color at that point. The amazing thing was that color was able to be added without breaking B&W receptions by the installed base of televisions. So, the lesson is: if you want to do something better, wait for somebody else to figure out the hard bits, and then copy from them, making a few improvements. You get to avoid their mistakes, plus you can use technology that is 20 years more advanced!
Also, there is a problem with changing the horizontal rate. The flyback transformers of older BW tv's could not have handled the higher frequencies without being ruined.
Movies are still 24 fps. But shown through NTSC you would have to make up for the last ≈6 fps to get to ≈30 fps. With PAL they just sped the film up from 24 to 25 fps, but speeding it up to 30 fps would be too ridiculous. Therefore they use 4 frames of 24 fps film to create 5 frames of NTSC video in a ridiculously complicated process called the Three-two pull down method. Read more here: en.wikipedia.org/wiki/Three-two_pull_down
"Just sped up the film" That's a major change in the timing of a film. Great directors and actors pride themselves on good timing. There was no pitch correction (for many years) so the audio was screwed up, too. 2:3 pulldown is quite simple. Europe uses the truly ridiculous 2:2:2:2:2:2:2:2:2:2:2:3 (Euro) pulldown. Read more here:_en.wikipedia.org/wiki/Telecine#Frame_rate_differences
Chris W, wow that is a truly ridiculous method, especially regarding the fact that fps will be less critical in the future as linear television slowly fades out. I've never actually heard of this method as it seems to be quite new it but it does make sense.
1:10 well, not an infinite amount of image. That would require an infinite resolution and probably an infinite amount of money. ...and that's kinda a problem.
Did you, a Brit, just write colour without the u? :o But including the u, there are six symbols, allowing you to make a colour rainbow, inside the word 'colour'! How dare you write colour without the u?!
Wow, this was really well done! Kudos Matt, I've enjoyed some of your stuff before and watched this video after export my own TH-cam video at 29.97 fps and wondering why, haha!
The only reason why 4.5 Mhz was hard set and unchangeable was because of the government over regulating things. 4.5045 Mhz would have made the math come out perfectly, but because the government set a hard number to ensure signals would have plenty of room not to interfere, that wasn't permissible. Just an extra .0045 Mhz, would have solved the problem, a hardly even noticeable dip into the 1.5 Mhz buffer. This is why government legislating regulations is a bad idea! Congress doesn't make it easy to adjust outdated laws, and no one wants to spend the insane amount of lobbying money needed to make what would be a reasonable change. And now, instead of being able to set frequency the easy way using the AC frequency tons of extra engineering had to go in to set the frequency manually. Making the TVs more expensive to make.
Well, yes and no. The NTSC compatible color standard was developed by RCA before transistors were common. and was developed on top of the existing monochrome system. When PAL was developed, it was years later, they had better technology to work with and it was a clean slate. There was an NTSC color standard that was not backwards compatible. The CBS Field Sequential Color system was released in the early 1950s and used a spinning color filter wheel in front of the tube. That system was quickly scrapped, but its technology was used elsewhere. Look here on TH-cam for videos of early color videotape recording from the 1950s. The RCA TK-41 cameras actually made a nice picture... and no transistors!
Very interesting video. One thing which weighted on the reason they did not want to change the number of lines: Back then. things were built to last (at least, to last much more than now) and the rate of change/progress was much lower. They had to respect all the people that were already owning a B&W TV, and that would not buy a color set before many years later. This meant the new signal had to be compatible. The 525 lines had to be respected. They could not simply say: "Hey, all of you with B&W TV owners, from now on, our TV signals will have too many lines for your TV sets, so throw them in the garbage and buy new ones!" Heck, they couldn't even change the number of lines lines to 524 or 526, either. That would mean that the slightly-too-small image (524 lines) would not reach physical line 525, the "half a line of zapping back to to of screen" signal would be confused with the the data for line 525 (making that line look like ugly junk), and the line 1 data of the next image would be interpreted as "jump back signal) (and skipped), and the all with a half-line delay desynch. Ouch. So you'd get 2 overlapped images offset by half the width of the screen, and that also slowly scroll up the screen every 17.5 seconds. Wow. Talk about looking at pure garbage! Same for 526 lines, but scrolling down instead. Yeepee. Basically, all the stores TV inventories would be ruined, or they warn well in advance and B&W TV sales would drop drastically in the couple years before the swap. You can easily see the huge uproar that that would have caused. Nowadays however, things are different, We're used to "use and throw away" and a much faster pace of change. When TV went digital, all analog TV owner got told (YEARS in advance): either buy a new TV with digital capability, or buy a 100$ separate special digital-to-analog TV Tuner & converter, that will convert the digital signals back into analog for your old TV. For years people bought TVs that had both digital and analog inside, until the actual signal swap which forced only those relatively few with really old TVs to either buy a new one or buy the special tuner. all in all a relatively painless migration. (well, that was when I stopped using my 10 years old TV lol to watch TV, only for my playstation and video cassettes, until the internet got me too). Some grumblings, but the transition went without too much of a itch. Even then, it took years and was planned for a very long time. Still, a 100$ tuner is still costly, and such a tuner/converter is a relatively simple piece of electronics. But much less than a brand new TV. But that kind of thing would have been impossible to think of back then. Can you imagine taking a 625 lines image, and having a "tuner re-parser" that rebuilds a 525 frame image "just for your old B&W TV". Skipping some lines? That thing would have need of a special "buffer" and been quite complex and would have overall cost much more proportionately to buying a new TV anyway. Many old TVs had straight out antennas jutting directly out of them, without "cable input". Because that was entirely before Cable TV! In fact, a TV back then looked more like a radio that also has a screen! So, there was no capability to "add a tuner". People also had the tendency to use their TV set not for a mere 5 to 10 years, but fully expected it to last at least 20 or more. Same as refrigerators, truly: refrigerators of that era didn't have all the bells and whistles, but those things are seemingly invincible and eternal, while today's refrigerators will last you about 8 years. If you're lucky. so they couldn't just Also, If a device able to grab in radio waves and convert them back to the old format for your old TV existed, that would flow the airwaves with way too much interference, too. And keeping separate frequency spans for B&W and for color would also have been wasteful. There was just no nice little cable input for a converter to be designed to attach to the TV. So it was the signal itself that just *had* to be fully compatible. Changing the number of lines was completely impossible for economical reasons, while very slightly changing the frequency was in fact possible, and the old tvs would still work ok with the new airwave signal. It's the initial 525 lines which was a bad choice. Or the assigning of a 4.5 Mhz wide airwave band. But to their defense it is extremely hard to predict in advance how tech will need to change. And I'm quite sure there was a strong reason why "525" was the number of lines initially chosen.
NTSC = Never The Same Colo(u)r ;) I've often wondered why US TV looks so smeared and washed out, I guess the 525 lines is a big part of it, though I think I read that the colo(u)r encoding is also pretty weak. Thankfully I suppose much of that is ancient history already.
I learned (back in school and talking with a BBC engineer) that NTSC was sometimes called "Never Twice the Same Colour", due to its phase-encoded colour being the same on every line; the colour phase signal could get offset on the radio transmission path to consumer TVs. Which is why there was Hue correction knob on NTSC TV sets. In the UK (and other places) we used the derivative PAL ("Picture At Last") system, which switched the colour phase encoding 180-degrees on alternate lines; so transmission phase errors could be cancelled in the TV receiver (I think in a big glass block) - hence the name Phase Alternate Line. I think.
"Thankfully I suppose much of that is ancient history already." Apparently not, both you bastards keep talking about these things in the present tense. I truly feel sorry for Europeans if you guys are still watching TV at the old PAL resolution. I have 4k TV none of this applies to me.
NTSC in the 50s: tweak this framerate down a notch for interlanced backwards compat Tech corps in the 21st century: yeah so we're gonna progressively scan everything at multiples of 60Hz; suck it 144Hz monitor manufacturers: hold my beer 165Hz monitor manufacturers: no, hold _my_ beer
2:45 So THAT'S why running the vacuum always messed with the TV in the pre-LCD years! I've had that question since before I could just Google it, and forgot it by the time I could. And now that I think of it, this makes me want to build a new alarm clock with an internal oscillator to get those likely seconds a year, from using the AC signal for timing, back.
+standupmaths A thought about increasing Lines to 625. 2 Main points :- (1) To increase the lines to 625 while keeping the framerate, would mean increasing the horzontal scanning frequency, which compared to the picture bandwidth means 'stretching out' the beam, 'going faster' for shorter time for each line. This will increase blur on the picture horizontally as the 4.5mhz bandwidth limits the speed can switch from bright to dark, sharp edges in brightness will become more gradients etc. (2) In any case, substantial change in horizonal frequency would then loose compatibility with existing TVs that try to lock onto the NTSC horizontal frequency from the mono-standard days, they may use a local oscillator with a simple phase-lock-loop and just not designed to "stretch that far" to a substantive horizontal frequency change. Let alone the various 'horizontal size' adjusters might need fiddling to widen out picture and soforth. The '29.97 hack' was a small enough change to remain compatible with existing mono TV sets.... Does that make sense?
Interlacing is a compromise, and has advantages (and disadvantages) of both ways. You get twice the frame rate, and twice the resolution, just not both at the same time. Interlacing makes movement look smoother. They could've gone with progressive scan from the start, but chose interlacing deliberately.
You don't understand a thing. When the American standard was created, it was a frame rate of exactly 60 Hz, and a horizontal rate of exactly 15,750. There were 10s of millions of receivers in North America, and in order to get approved, the NTSC came up with a way of shoe-horning a color sub-carrier and information, so that all the B&W televisions would still function and new color tvs would also work. The engineers brilliantly made it work, unlike the U. K. Europe and the other PAL countries, where old receivers were obsolete and they were years later than North America. This was not a whim, old tvs worked as always and new color sets brought color to the home. Absolutely brilliant!
Never have I ever got a better lesson in maths, electrical engineering, electronics, history and that too, combined. If teachers explained this way, the world would have been a different place.
All Cretans are liars ... and all cretins are sincere. Which one do you prefer ... said the philosophy geek ... not, the 6th century BC Greek, Epimenides. P.S. Yeah. My command in English grammar sucks. I have prepared a standard issue Luger for the Grazis
When I wrote my last comment I thought it was a paradox. But if you look closely, it can simply be either a true or false sentence. What I really wanted to say is: This sentence is true.
I hated how a lot of video games in the 80's/90's had black borders on them. Because they were coded at 525 lines, and our TV's had 625. The just filled those 100 extra lines with blackness.
Patreon doesn't sound so bad...problem is I don't really have anything to donate so I'll leave a comment here to let you know I'm one of your people who stuck around.
I love when someone finds something that is not on the internet and makes it their job to put it on the internet, I try to do it myself, great video!
+Cody'sLab It's why we do what we do. And now the internet knows that the toilet is a terrible option when you have surplus mercury to dispose of.
@@butwhy4579 And you ruined it
@@butwhy4579 no
Delet ur comments then
pprmograficp
Great explanation. Me and my 2.97 friends thoroughly enjoyed it.
Bryan Vas cannibalism
@@jeromej1234 r/cursedcomments
You have friends? Lucky.
What did you do to Jerry?
@Bryan Vas you mean, what happened to the remaining 0.027 of a friend don't you?
So many weird standards in the U.S. Sometimes I wonder if a dozen eggs isn't really 11.951 of them.
Nevermind the whole "bakers dozen" thing
+Kitsuneoni bakers dozen has been around for thousands of years. It has nothing to do with America
I don't get the use of a non-metric system in this day and age though
You do, since you use hours, days, weeks, months, and years. It'd make more sense if an hour were 100 minutes, a day were 10 hours, a week were 10 days and a year were 10 weeks. Metric time does exist, but since we're all pretty much used to our weird system of measuring time, we just choose to stick with that.
Our current system uses highly composite numbers which are more versatile though
I've always thought RCA engineers did a pretty genius job adding color to the B&W signal without making non-color TVs obsolete.
Dave Holden yeah it is amazing how they pulled that one out their arse...I remember NTSC stood for never the same colour, SECAM Stood for system enitirely contrary to the American method, and PAL... peace at last....
NTSC: Never Twice the Same Color
You are absolutely correct! It was not perfect, but and outstanding job of integrating old technology.
I think they did the best to make the smooth transition from B&W to Color. If they changed the frequency or the amount of horizontal lines, it would make all B&W TV sets unusable, I guess. Some CRT expert here can comment for us!?
@@pangwa82 Yes, you are correct. If they changed any aspect of the existing waveform standard, they'd 'break' all existing TVs. Not only could they not change anything already working, but they had to *add* color to the existing standards, *without* it affecting B+W TVs.
For those that don't know, the overlaid much higher frequency wave on top of the B+W wave. B+W TVs weren't affected by these newly added waves superimposed onto the B+W signal. The addition was a 'color burst' at the start of each line of horizontal B+W data, and then the color carrier was made to be out of phase with the color burst, and the 360˚ phase were assigned to colors! That is, at point A, the color wave is the same as the color burst, and so the TV shows red. At point B, the wave is 180˚ out of phase with red, and the TV shows red's opposite color, cyan. Meanwhile the amplitude of the original B+W wave is STILL telling the TV how *bright* to make that pixel.
It's amazing what engineers accomplished without computers and modern electronics!
The BIG MYSTERY is why, despite:
• The death of CRTs
• The death of NTSC
• The death of analogue broadcasting
• The death of "standard definition" video
• The introduction of 720p, 720i, 1080p, 1080i, 4K and 8K
• The death of VCRs
• The death of tape-based systems in video/TV production
...this ridiculous frame rate still exists. I beg EVERYONE in TV/video production, please ditch 29.97! It'd be exactly like a musician of today never recording a song over 4.5 minutes because otherwise it wouldn't fit on a 7" 45rpm single!
Limiting songs to 4.5 minutes constrains an entire art form. Having an awkward frame rate for your TV standard is a minor inconvenience to a tiny number of people. It's not "exactly like" it at all.
@@EebstertheGreat tbf how many songs are over 4.5 minutes. Only inconvenient to a small number of artists and barely any that would be played on the radio
@@isaac_aren In some genres, every song is over 4.5 minutes.
@@EebstertheGreat I wouldn't say the entire TV industry* is a "tiny number of people".
*I'm saying the entire TV industry, even though it's only America who uses these ludicrous frame rates because it's almost guaranteed that at some point, almost everyone working in TV will have to deal with some kind of video that originated in America.
@@tgktgkify It's not the entire TV industry who has to worry about the 0.1% difference in frame rate, just some techs in specific situations converting frame rates between formats. Everyone else involved (producers, actors, writers, cameramen, etc.) never have to think about it.
My goodness you put a ton of effort into this video! I love how the motion graphics are in time with you speaking! Super well explained!
+Make Something Thanks! I was very pleased with the tech set-up required. Can't believe it all worked!
Any chance of a stand up gig here in Australia? :-)
Love your sense of humour, Brit humour and Aussie is seemingly closer than the US.
The huge irony is that NTSC does not have line by line phase reversal - aka Phase Alternating Line aka PAL. From memory the rest about adding the colourburst is correct, but that isnt, its the colourburst itself, it doesnt phase reverse. @Standupmaths - im kind of amazed you didnt mention even NASA would use the freq of the colourburst as a freq reference. I read a great anecdote where a TV station had their rubidium clock break down and had to return to an oven compensated xtal, and then was contacted by them asking what had happened to the signal and subsequently supplied with a ceasium clock for their colourburst :)
It was really nice
Next, can you do a video on why hotdog packages don’t match the number of buns in bun packages? I imagine it has something to do with the different resonate frequencies of the two foods.
you deserve more hype
Greg Belcher I figure the difference between the number of hot dogs in one package and the number of hot dog buns is because the companies that make them want you to buy more and if you buy 1 package of 10 dogs and one package of 8 buns, when they are all used, you have 2 left over dogs. If you want to use the last 2 dogs, then you might want to buy more buns, but then you would have 8 leftover dogs and the cycle of buying dogs and buns continues until you reach a common multiple of both dogs and buns, which is 40 dogs and 40 buns. For using even numbers of dogs and buns, there are no two better reasonable numbers for small packages of dogs and buns unless they are the same number, but the companies want to maximize their profits by keeping the customer buying dogs and buns.
I think 10 packs of hot dogs and 8 of buns should get you there right?
@@demodemo5146 or 5 and 4.
The reason they don't match is due to the metric system. The companies making hot dogs readily took to metric's base 10 system while those baking buns stubbornly held onto the ridiculous imperial standards.
No... I'm not being serious... why would you even ask that?
Something to note is that while NTSC is 525 lines, only 486 lines were actually used to visually show the image. The other 26 lines were used for vertical synchronization and retrace. Thats why SD digital is 480p, as thats equal to the actual visual representation of NTSC. PAL was about 600 lines of visible footage, so if you ever have on your hands a master tape of a European TV show, from BetaCam or something else, it makes more sense to up-convert it to 4:3 720p HD, or else you will be losing a bunch of quality.
Real SD digital is 486. DV is 480.
Exactly, I rather over sample the video and get as much information from the picture as possible even if 720P or 1080i seems overkill. Analog video does have high frequency peaks and the professional analog recording equipment could capture a lot of information. Watching old Dr. Who episodes on blu-ray shows how good PAL video was, as far as the in studio recording elements were. The outside scenes were usually done with film, and those were re-transferred from original footage if available.
@@randystuehm7924 It's 483.
I have just spent too much time searching for my reference material! What I found was that 525/30 according to the NTSC spec, has a total 40 lines of blanking and thus 485 lines of active picture per frame. 625/25 according to the EBU spec has 52 lines of blanking and thus 573 lines of active picture. In practice this might vary, usually by rounding down.
I did find two useful links. This one has a simple explanation of NTSC with some humour: www.sxlist.com/techref/io/video/ntsc.htm This one is more technical but has tables for everything, and links to more info than you would imagine: enacademic.com/dic.nsf/enwiki/14957 That one appears to be translated from German, so there are some quaint bits.
@@marcusdamberger Yes. BBC ALWAYS shot outdoors on 16MM film, and indoors in a TV studio on tape. You see this throughout the 1950 to around the 1990s, until decent tape-based recorders and cameras became cheaper than shooting processing and transferring film. Dr. Who is a great example, as is Monty Python
I like how the Patreon screen totally screwed up the white balance. LOL
+Robert Baltrusch It takes a cut of my white balance.
Excellent video though. This is super relevant to the FPV hobby, and no one has covered it as well as you have.
Don't you mean exposure?
White balance is yellow/blue tint. Do you mean exposure, which controls the brightness of the video? ;)
Yes, I did mean exposure, and white balance. He's wearing a white shirt next to a white monitor, that's glowing white. But the exposure was most affected, you're correct.
Early television engineers were damned smart. Make the best out of a crappy situation due to the limitations of physics and find a solution. And they did it by using their brains and education with good old pencil and paper. Hat off to them!
Well they sure as hell weren't any ordinary people..... most of them were former Nazi scientists!
Euzifyy How do you know that?
Johnny Appleseed Color TV first appeared in the early 1950's and the second world war finished in the 1940's
It looks like I found my lost twin.
Euzifyy Everyone's a Nazi scientist these days. What's new?
“PAL was better because it was higher resolution”. Not true. The reason was much more interesting. Colour information was coded in the phase of a sub carrier relative to a short burst of that subcarrier at the start of the line. The problem with NTSC was that the received signal could have phase errors due to things near the aerial blowing around in the wind. These phase errors would get turned into distracting colour (hue) errors. In PAL (Phase Alternate Line where the phase swung +/- 45 deg ) each tv line signal was stored in a delay line and averaged with the next line. The vector sum turned phase (hue) errors into amplitude (brightness) errors which were visually unnoticeable. That’s the real reason NTSC was mockingly called ‘Never the same colour’
Exactly. But what about SECAM?
Never Twice (the) Same Colour
I was at BBC Engineering Training Department Wood Norton in 1980 (a former stately home which doubled as UNIT Headquarters where Jon Pertwee first appeared as Doctor Who). Our lecturer, Pete Harris, had a humorous take on how the pros & cons of the three colour systems related to their names. NTSC was a beautiful work of genius but it suffered from one major problem - hue errors. (Thus American TVs all needed a 'Hue' control.) SECAM (Séquentiel Couleur À Mémoire) was fantastic for transmission (and protecting French manufacturing on the orders of Charles de Gaulle) but was mind-numbingly useless in the studio. PAL (Phase Alternating Line), however, took the otherwise excellent NTSC, built on the American experience and elegantly solved the hue problem. Thus, we had the three designations:
NTSC: Never Twice Same Colour
SECAM: Système Extraordinaire Contre les Américains
PAL: Perfect At Last!
The wind did not cause hue errors in NTSC. The color subcarrier and the main carrier may shift together a little but, but, since the color subcarrier is detected as the difference between the carrier and the subcarrier (a much smaller figure than the main carrier), hue shifts did not occur.
If the picture is heavily affected by dynamic multipath (e.g. trees blowing in a storm) can cause a loss in horizontal synchronization. When the back porch color pilot is freed from the synch, anything that occurs in the horizontal retrace becomes a false color reference.
@@1L6E6VHF That's not entirely correct. It's not a question of subcarrier and "main carrier". The colour information was sent on a subcarrier (a sine wave added to the video signal - 3.58MHz in NTSC and 4.433MHz in PAL). The instantaneous saturation & hue of the picture were given respectively by the amplitude of this wave and its phase angle with respect to a fixed reference. The angle of the fixed reference was communicated to the TV set by a short sample of about ten cycles of subcarrier at the beginning of each television line (the Colour Burst) and then maintained throughout the duration of the line by the BLO (Burst-Locked Oscillator) inside the TV.
Ah, 15,750 cps, I remember that number. The old "horizontal synch tone" I used to hear whenever the TV was on. My Dad declared I wasn't hearing it, of course what was really happening is *he* couldn't hear it.
I can still hear it at 58. I still watch a CRT TV.
Joe Shmoe and do you still wave your hand over the screen and feel the static electricity?
Yup. You got home late at night, you could hear if the TV was still on with the sound off, meant you were in trouble.....
Older people lose hearing of high frequencies
Man, I remember that. That barely audible high-pitched whine... been so long since I've used CRT TVs or monitors that I'd forgotten about that. That's so nostalgic... I remember staying up all night watching Doctor Who on PBS on my little hand-me-down 13" black & white TV sitting next to my bed... wow. Now I want to go watch Doctor Who. lol
The video is pretty interesting but I must highlight that building up the presentation on that screen had to be a tedious job, so congratulations for all the time you and your team took for preparing the whole explanation!
+kundogb Thanks! But this video was just me. If my patreon goes well I might be able to get my team involved.
Very impressive. Great presentation. Big fan. Thanks for making math/maths (and old TVs) so much more understandable.
“When you do things right, people won’t be sure you’ve done anything at all”. Godly advice, if I do say so myself. ;)
That is from Futurama. I saw it a few hours ago.
>29.97 fps
>inches, feet, yards, miles
>month/day/year
>fahrenheit
>handegg
*_UNITED STATES OF MERICUH_*
You forgot paper standards.
An insult to the word "standard", really ...
Well Fahrenheit is used as a general sense of how hot something is. " It's 30 degrees? Oh that's cold. It's 100 degrees, 100 is a lot, so its really hot." Ask water how hot it feels and you get Celsius. Simplicity.
Horny Fruit Flies writes:
">29.97 fps
>inches, feet, yards, miles
>month/day/year
>fahrenheit
>handegg
UNITED STATES OF MERICUH"
Well, MERICUH is not how it's spelled, so that's not a valid complaint! (^_^)
I thought the video explained why we have 29.97 fps. Bad luck, basically, and a desire to maintain backward compatibility. The numbers just happened to work out better in Europe.
As for units, you use the right ones for the job (just like tools!). Feet are useful for high-energy physicists because light travels 1 ft. in 1 ns. So this is useful for estimating delays from cables.
Month/day/year. You find day/month/year better? The best is really the ISO format: yyyy-mm-dd. And I wish the world would switch to that, but current date formats are like QWERTY: too deeply ingrained. I myself find writing m/d/y natural, just from growing up in America.
Fahrenheit. I think this is more fitting for normal use. A Celsius degree is a little too large when used for indoor and outdoor temperature. Fahrenheit makes a weather map better, too. An area of 20's C would be too wide. Fahrenheit gives you "better resolution" while still working with integers. Scientists outside of the weather business typically use Kelvins and Celsius. You use the right units (tools) for the right job!
Handegg? OK, I looked it up. To each his own.
If you favor metric, or SI, units, I can tell you all sorts of non-metric or non-SI units that are used by scientists: atmospheres, G-forces, parsecs, feet (already mentioned), hell, let me just quote an old post of mine from another website:
"Speaking of units, scientists frequently use non-metric units: light-year, parsec, astronomical unit (equal to the radius of the earth's orbit), (an) atmosphere (a unit of pressure, though more for convenience when precision is not paramount), G forces, electron volt, barn (a barn is 10^(-24) cm^2), fermi (which is 10^(-13) cm). These last two are based on a metric unit, but so is the inch (defined as 2.54 cm), so it's just as "bad", sort of). The electrical charge of particles, in many cases, is more conveniently measured in multiples of that of a proton, as in the charge on an electron (which would be -1), or quarks, which, depending on which quark you're dealing with, is +/- 1/3 or +/- 2/3 of that amount of charge. There's also a foot (of cable, or patch cord, if you will), which is how far light and electricity) travel in one nanosecond. This is useful in high-energy physics experiments for estimating delays. I believe calories are still used by some, though I'm not really sure. Add to all this units of time: years, months, weeks, and days are not metric units, yet scientists use days and years, at least. The dinosaurs were wiped out 65,000,000 years ago. No one converts that to seconds. Angstroms are still used (based on a metric unit, though). There are probably more.
Bottom line: Use the units that are appropriate for the job."
I never got the argument that Fahrenheit gives you better resolution. Why would you ever need slightly better resolution for Temperature, and if you do: Why not use the Celsius value with another digit?
Also, the estimate that light travels 1 feet per ns is just that; an estimate. The estimate has an error of about 1.7 %. Pretty sure mostly American or English engineers use it, and for any serious calculations you'd use meters.
We use the units we're used to. It's an important part of our culture.
To be precise, for NTSC 4.5 MHz is the frequency difference between the video carrier and the audio carrier for each (6-MHz) channel. IIRC, the reason that this value could not be changed (leading to the math discussed by Matt) was that if you moved the audio carrier (say to keep 30 frames per second with 525 lines per frame as well as the half-integer requirements), the audio demodulators of the existing B&W TVs would be unable to correctly demodulate the audio. Analog TV audio for NTSC was frequency-modulated (as well as pre-distorted, but that’s a topic for another discussion), and I believe that the analog circuitry used at the time could not tolerate much error in the location of the audio carrier. The video demodulation, on the other hand, could tolerate a much larger relative change without needing redesign (say 30 Hz to 29.97 Hz, or around 1%).
I'm not sure where you got this from but it contradicts what the main problem the standard was trying to eliminate. The new subcarrier (3.583125 MHz, for color) had harmonics that interfered with the FM sound subcarrier (4.5 MHz) creating a constant buzz in the audio. By lowering the framerate along with the SC frequency the noise in the audio was reduced (beat frequency was now outside the audio bandwidth) and everyone signed off. Lots of compromises b/c no one wanted to reinvent the wheel with the color SC again.
Since it's not allowed to go outside the 4.5 MHz window, couldn't they just change the window slightly by moving it *_inwards_* instead?
@@Anonymous-df8itInteresting proposition.
For example, the integer multiple could have been reduced to, say, 280; with 525 scanlines at 30 Hz, this would bring the bandwidth down to 4.41 MHz.*
* _4.41 MHz is a square number, if that livens things up at all..._
@@keansakata1015 It sounds like you're just repeating what the original commenter said, so there isn't any contradiction
@@SeanHarding-nv9li Where are you getting the bandwidth values from?
Growing up in this digital age, where FPS is usually expressed as an integer, I never knew why my video editing software always defaulted to such a specific decimal value. The answer was much more fascinating than I expected. Thanks for the info!
Nice. I remember changing my DVD player output from PAL to NTSC, and see the screen blink, colours go haywire and picture area shortened vertically. This video explains it clearly.
That's a good explanation except for fact that it's not 100% technically accurate. 29.97fps * 525 lines * 286 is actually equal to 4,499,995.5. Although we nominally refer to the NTSC framerate as 29.97, that's actually just an aproximation. The true framerate is actually 30/1.001, or about 29.97002997002997... When you plug 30/1.001 into your equation, you get EXACTLY 4,500,000Hz.
Neat.
It's nice explanation but based on wrong facts. PAL channel is wide enough that you don't need to mess with Δ2 = ODD2 * fh/2. Sound use FM modulation, so there is no way to interlace sound spectrum and chroma spectrum, so exact Δ2 doesn't help much. In Europe we have 5,5MHz, 6,0MHz and 6,5MHz sound IF (Δ2 is different) and all systems use the same PAL 4,43MHz frequency.
PAL creator Walter Bruch choose chroma frequency other way - PAL use the same horizontal (15625 Hz) and vertical (50Hz) frequency like B/W standard, but chroma frequency was shifted - fv/2 was added to minimize artefacts. In fact in PAL it must be ODD * fh/4 (because of PAL phase alternating line by line) + fv/2. Exactly: 1135 * (15625Hz/4) + (50Hz/2) = 4,43361875MHz
So PAL never used chroma frequency ODD * fh/2 ! It was only used in experiments with NTSC based system in Europe in early 60's.
+xsc1000 The explanation is specifically pertaining to the North American NTSC standard. PAL was developed after NTSC so the engineers were able to avoid many of the inherent flaws that plagued us here in the USA.
You count 6MHz bandwith for PAL for Δ2, but in fact it is 5,5MHz in original German version, 6MHz in British version and 6,5MHz in eastern Europe version.
If NTSC changed horizontal lines to 625 (like you offer), none of B/W set would be compatible because of horizontal oscillator changed frequency. Also horizontal resolution would be low. You can count bandwith you need for Y (luma) signal by this equation: B= 625 (horizontal lines) * 625 * 4/3 (vertical lines) * 30 (framerate) /2 (two pixels create sine wave period) = 7,8MHz. But you have < 3.5 MHz for luma in NTSC, so horizontal resolution would be less than half the vertical resolution.
"The true framerate is actually 30/1.001, or about 29.97002997002997..."
So NTSC TVs are more accurate timekeepers than atomic clocks?
From what I remember from working in broadcast TV, the reason they stuck with this as a standard was for backwards compatibility. They wanted to still be able to broadcast the same signal so it works on the millions of black and white TVs that were already sold to consumers, and to enable TV stations who invested millions to not have to scrap everything and start over.
How many people are still using black and white tvs in almost 2023
@@Xnoob545 Plus this is specifically for analoge signal. So why people insisting on using 23,976 and 29,97 fps for digital content, I don't get.
I am telecommunications engineer and I never had so good explanation of the whole thing like you did right there in this video. Not to mention how entertaining it was. And a good hearted joke from my side... I learned in school that NTSC stands for 'Never The Same Color' and PAL stands for 'Perfect At Last' ;)
And the French SECAM system stood for "Something Entirely Contrary to the American Method"...
@@bobweiss8682 System Entirely Contrary to the American Method. I used to know how to write this in French, but can't find the note I wrote back in the late 70s!
wow. I could never expect an oldschool TV to be usable to achieve a well edited youtube video. nicely done parker :)
I'm looking forward for that BTS video :D
Video editing is a magical thing.
It might actually be some kind of computer monitor. It's at least a high end Trinitron.
RogerWilco I'm positive it's a tv monitor. he probably has a wacky adapter to convert from a pc/circuit board HDMI/VGA to the tv format
look right at the end when the Patrion logo is on the CRT you can see a black stripe slowly edging downwards - a mismatch between 29.97 and 30, Close enough to be usabe
This is really cool and interesting!
I do enjoy your content Matt.
+Vicvic W Thanks, it's fun to make! And now I have a spare TV…
Well congratulations matt 😊
By the way, I love your vids
pls keep making amazing content like this...
I know this NTSC-pun: NeverTheSameColor
😂
how do you get 152,265 subscribers precisely
That line through the patreon logo that’s _ever_ so slowly moving down the screen is the _definition_ of rounding error.
When I worked in a post production house in Hollywood, the saying was:
NTSC = Never The Same Color
Also, in order for timecode on broadcast videotapes to make sense with the 29.97 framerate, they developed "drop-frame timecode," typically denoted with a semicolon or period after the seconds [HH:MM:SS;FF]. For every minute not ending in a zero, two frames were skipped in the timecode. If they hadn't done this, then every hour of timecode would have an additional 3.6 seconds of real time.
Yeah, I've researched this because why not-yeah, "because why not" is why I research most of the things that I do.
So 00:00;00 is a real timecode, as are 00:00;01, 10:00;00, and 10:00;01, but 01:00;00 just doesn't exist, and neither does 01:00;01, or 01:00;02 or 01:00;03 in the case of 59.94fps.
This drops 18 frames (29.97fps) or 36 frames (59.94fps) every 10 minutes (18000 frames in 30fps or 36000 frames in 60fps), leading to a frame rate of 17982 or 35964 frames per 10 minutes, or 29.97 or 59.94 exactly. NTSC is actually 29.970029 970029 97... frames per second, which means that timecodes with the SMPTE drop-frame correction still drop a frame every few hours.
@@meta04 I remember this too well, it is burnt into my memory. Generating SMPTE on a brain dead 8bit.
Who on earth is going to notice the extra 3.6 seconds of real time? Also, you still end up with the problem that every hour of timecode is short 3.6 milliseconds of real time (4500000/(525*286) isn't exactly 29.97)
@@Anonymous-df8it We're talking about TV networks who sold advertising space by the second, so they needed to be precise in how everything was measured. Also editors would often have to deal with audio coming from different sources, so having the sync drift by 3.6 seconds per hour would be catastrophic. Those are just two of many reasons why precise timecode was important.
@@lednerg Why isn't 3.6 milliseconds per hour catastrophic?
The whole point of NTSC color tv was to put in a standard in which people who still owned black and white sets (vast majority) could still see color broadcasts and color tvs could still see black and white broadcasts, this was referred to as "compatable color". If they were to have adjusted the horizontal lines like you suggest the would have made a signal that no tv could display, therefore defeating the whole point of their efforts. In Europe, when PAL was introduced, anyone still using the old 405 line black and white sets, just didnt get to see the new color shows and anyone who had a color tv couldnt see the old programs.
All color TV Systems (NTSC, PAL, SECAM) had to be backwards compatible to black and white TV standard. It would have been too costly to broadcast the same content simultaneously with two different standards. At introduction of color TV most pople still had b/w TV sets and only a few shows were actually transmitted in color.
@@oldSwede65 Also most of Europe were broadcasting 625/50 before they started broadcasting in colour! There was overlap with 405/50 staying on for some years until all the old VHF transmitters were replaced by UHF. The programmes they broadcast were the same, just in B&W. The BBC made everything in colour 625/50, and there were standards converters at TV Centre to down-convert to 405. I the French even had some 819/50 B&W transmissions running after they converted to 625.
NTSC = never the same colour twice ! Or so it was often described.
@@oldSwede65
And yet, the UK did exactly that for nearly 20 years (if you count the Trade Test Transmissions on BBC 2, which, though illegal to watch, were being seen nonetheless, as the law was virtually unenforceable).
The amazing side effect was that color signals gave better black and white images on black and white TV sets.
I always assumed it was a rounding problem when converting from imperial time to metric time.
LOL, best comment.
Does anyone know if the 29.97 frames per (metric) seconds is an integer when converted to the imperial feet-fahrenheit time unit?
Ummm, the current definition of the second was the result of a collaboration between the British National Physics Laboratory (NPL) and the United States Naval Observatory in the late 1950's. (You might be able to guess the nationalities of those two institutions.) The effort was aimed at defining the atomic (silicon) second to match as nearly as possible the 1898 definition of the ephemeris second, as given by Simon Newcomb, Newfoundland born director of the United States Naval Observatory, employing the lunar theory of British born Yale professor Ernest William Brown. The modern second is pretty much an Anglo-American project.
Jim DeCamp, you know hes joking right?
On youTube (and especially numberphile) one can never be certain. I guess I took nationalistic umbrage, given that the definition of the second, at least since the late 19th Century has been pretty much a U.S. project, with substantial help from the UK's NPL.
I suppose you're going to tell me that we're nitwits for not using a rational and sane AC frequency like 50 Hz, or a "more efficient" mains voltage like 220V.
As a curiosity, Brazil used a NTSC-PAL hybrid called PAL-M, which featured 525 lines, exact 30 fps, and the PAL color encoding scheme with almost the same chroma carrier frequency as NTSC.
Exactly! It would be great if Matt made a video about it. PAL-M merged 30 FPS with perfect colour reproduction.
Yes very similar but being PAL there had to be a quarter-line offset so the frequency changed. Another difference between PAL-M and European PAL is that there in no 30Hz subcarrier offset (25Hz is used in Europe). This offset was an afterthought by Dr Bruch and has caused us heartache in Europe with editing.
@@dhaen Ah! The glorious days of eight-field editing!
"Standards have to be continuous . . . for some definition of continuous."
Gotta remember that one.
In fact, in the UK, the black and white system (which used 405 lines, thus incompatible with colour) wasn't switched off until 1985.
The most amazing thing in this video was seeing a CRT television........
My sister who is pre 10, has never seen a CRT computer monitor.
Sony Trinitrons are generally very good ones, I'd have kept it too. I use mine to play arcade games.
I still have a CRT television, fully functional
Kind of an odd fact but Super Smash Bros Melee on the gamecube is primarily played on CRT tvs because there is less lag. In fact watch any ametur to professional SSBM match and they are playing on CRT tvs. They are in very high demand right now among the Melee community as good ones are becoming harder to find
*COUGH COUGH* 144hz 1MS Response Time BenQ screens *COUGH COUGH*
Great video, and very informative. I have long wondered but never bothered to check.
(Phase reversal requires that the phase of the wavefunction describing the signal be adjusted by precisely one half of a wavelength for each color frame, hence the need for an integer multiple.)
+TomatoBreadOrgasm I started reading about it because it sounded interesting but realised it was slightly too off-topic for the video.
standupmaths Well it didn't diminish the quality of a great video, in my opinion.
+standupmaths, are you implying that maths is off topic?
They did not just take 60 Hz to match the electricity outlet, since synchronization could be set to anything, they did it to avoid interference-flicker with studio lamps and lights that are also connected to 60 Hz outlets.
You just gotta love from back in the day when someone put the TV on, and your computer screen seemingly degaussed.
That's litteraly what Matt says though
I'm pretty sure that most TVs had their electron beam deflected by the environmental 60Hz electromagnetic noise, this would cause the screen to move vertically at the beat frequency between 60Hz and vertical scan rate. That would be quite annoying though I'm guessing 29.97 is close enough that a movement that takes 30 seconds to complete would not be noticeable.
Can you tell me why they didn't just rectify 60hz AC into DC? Seems like a lot of trouble for something that has such a simple solution.
@@CSGhostAnimation - Yes, Thomas Edison's plan of transmitting power as DC instead of AC would solve the problem. It would also create far bigger problems.
The problem is the current that's not inside your TV set. It creates a magnetic field that deflects the CRT electron beam. The frequency difference between the external magnetic field and the vertical scan rate is what you see as motion on the tube.
Unfortunately, changing the number of horizontal lines in a North American TV picture from 525 to 625 would have destroyed backwards compatibility with the existing black and white sets.
Not really, vintage tv´s had vertical, width, horizontal controls to ajust the picture on the tube
It was more easy to implement.back in those days.
I remember a guy in Portugal receiving by sky skip a freak signal of Brazilian tv that came in,and all he did was ajust his 625 50hz tv to 525 line 60hz on a small portable black and white set. using the vertical width controls
Brazil does use PAL but on 525 60hz
But the tv been an old b/w did not have to deal with other things of the signal.
The video is on youtube
Yeah, but every time you change channel? Some channels (some SHOWS) were B&W, others color. They coexisted.
Brazil also uses PAL.
@@voorhes80
PAL-M 525 60hz
@@angelsmith1761 You are assuming that existing TV's had horizontal and vertical frequency controls that would have sufficient range to make such large frequency adjustments and that the circuits would still have performed properly with such a large deviation from what they were originally designed to work at.
It's awesome when you work through equations like this :) I especially like that, instead of a blackboard, you utilised a television.
Matt i read your book, and i really enjoyed it. So i think that a good petreon reward would be a few more chapters to read. C:
+Mads Philipsen I'm writing a new book now. I could release some chapters early to patreon supporters?
Me too
It would be really cool if it was like a chapter pr month.
+standupmaths Stuff to Create and Have in the 5th Dimensoon
Mr Calligraphy If you've read the book you know it already talks about really high dimensions too.
Great little animations on your ‘tv’ there. Excellent work.
How did it feel to intentionally misspell the word colour as a British person?
+VeryUnfriendlySpoon It felt dirty.
standupmaths
As a Canadian I have to deal with that dirty feeling very often.
It's not misspelled. It's a different dialect.
Gregory Kanniard its misspelled
Jackson Kennedy different dialects spell things differently. Believe it or not, Europeans spell some things very different than originally intended. Just like Americans
Also changing the number of lines in the signal would completely brick the older TVs, introducing an odd, skewed horizontal rollover as the greater number of horizontal lines would cram the same number of pixels into less horizontal space.
A small change to the number of lines would not have caused any particular difficulty with consumer video equipment. Until the late 1990s, most video game systems output video that was significantly different from what the NTSC specified, but TV mostly coped with it just fine.
Yes, a lot of early gaming and home computer systems produced signals that were more than a bit off, but the NTSC engineers were tasked with creating a standard that would be least disruptive and compatible with older B&W sets. Changing the vertical scan rate by a tenth of a percent was very likely to work on all receivers; changing the number of horizontal lines by 20% would have produced the artifacts seen with many games & computers, like jittery pictures, tearing, and flag waving.
I don't believe any of the European color standards were compatible with their earlier B&W signal. They saw the compromises the NTSC engineers made and decided to just abandon the old standard and start over for a better color picture, also a reasonable engineering decision, but it forced customers to replace their sets.
All the European colour standards were fully compatible/transparent and usable on older B&W TVs. No sets needed to be replaced (until digital broadcasts came about, but that was much more recent).
"Why is TV 29.97 frames per second?"
because peasantry
***** edgeyMcangister
But it updates 59.94 times per second. That's why games still run at 60fps on CRT TVs.
If someone is more informed than me, please feel free to correct me, but I believe that the 60FPS (and 50 for PAL) is only the first round of scanning (meaning half the scanlines). When you combine the two different scans in order to have a "full image", it totals to 30FPS.
So, 60FPS for one out of two scan cycles, 30FPS for two out of two scan cycles.
Karolos Triantafyllou Sorry, no. The "frame" as described by NTSC/ATSC or other interlaced formats is actually a combination of two different images (these are called fields). NTSC has 59.94 distinct images (fields) per second. The 30 frames per second idea a very bad naming scheme.
SNESIvan
So the naming convention is untrue? Interesting. Could you point me to somewhere were I could read more about it? It seems interesting.
90 seconds into the video and I'm blown away by the wicked in-camera special effects
PAL is more cinematic!
you stole my words sir +Guitar Lesson
grande1899 omg 😲 YOU AGAIN
The lowest common multiple of PAL 50hz and movies 24hz is 600hz
The lowest common multiple of 60hz and 24hz is 120hz.
Sorry, PAL doesn't have enough prime factors in common with cinema for my taste.
Patrick Wise You're forgetting that as explained in the video, NTSC is actually 29.97 FPS an not 30/60. The lowest common multiple of 24 and 29.97 is 23976. Checkmate :^)
although what's funny about this, is that on UK TV, films, shot at 24fps aren't "mapped" (3:2 Pulldown i believe it's called) like on the NTSC system, we simply show 24fps at 25 fps. This is why if you check running times of movies shown on UK television it is about 4% shorter than the actual running time.
Also, now we are in the age of 1080P and soon 2160 P or even higher, why are we still having to even think about drop frames and 29.97 frame rates?
NTSC stood for Never Twice the Same Color.
SECAM was System Essentially Contrary to the American Method
PAL is Perfection At Last
Ha-ha, I just posted the Never Twice the Same Color comment before I read yours.
HA! I'd never heard the SECAM one before. =:oD
Systéme Extraordinaire Contre les Américains!
Actually, NTSC stands for Never The Same Color, since color hue was based on that signal phase shift, which was EXTREMELY fiddly, and prone to all kinds of error, since it depended on the signal oscillations following a rigorous phase timing, which could shift with factors such as length of cables in a studio. In fact, those famous color bars were created as a way of calibrating the color as closely as possible with the naked eye.
Fun stuff. The mechanics of an NTSC signal "frame" is pretty fascinating! It sucks by today's digital standards, but for what they had at the time, those engineers came up with some creative ways of packing information into a signal!
The way I heard it way back when was Never Twice the Same Color.
You have the "cause" and the "effect" backwards! The NTSC color subcarrier was 3.579545MHz which was the closest "easy to manufacture" crystal that would get close. But the oscillator needed to stay in phase from the end of one video frame to the start of the next or else the color would drift. The shortened frame rate was to keep the "ScH Phase" (sub-carrier to horizontal) correct. You work that backwards to get the numbers in your presentation! The ACTUAL frame rate is in fact 30 x (1000 / 1001) and you need about five digits of precision. 30 x (1000 1001) comes to 29.97002997 … but notice that there are two trailing zeros after the 29.97 which is the only reason why it's "close enough". But you are absolutely correct - dealing with non-integer frame rates (and interlaced video in general) have been the bane of the broadcast engineering community for decades!
There were several attempts at coming up with a color standard. Finally, it was realized that with the expense at the time of television in general--and especially the new color sets--you would have to make it "backwards compatible" to the existing B&W sets or you would be selling zero color TV sets and would fail. So they did, and made the best of a bad situation. PAL is superior in many respects--and is so because it started from scratch with the lessons learned by the compromises that had to be made in the North American system. Had that been a real option for the American engineers, they would have loved to start over and make a clean solution. But marketing always asks for miracles, and it's up to engineering to deliver them (compromised as they may be).
Have to add that at the time devices were meant to last forever. You could not simply ditch a B&W set because it's outdated due to a standard of color tv being introduced. Of course things have changed...
@@PR-fk5yb In the 1950s TVs were far more expensive relative to average earnings than they are now. Colour sets even more so. Although NTSC colour transmissions started in 1955 it wasn't until about a decade later that colour TVs outnumbered B&W ones in US homes.
@@PR-fk5yb Yeah, imagine if Apple had invented it.
@@zoewells3160 lol remember that story : What if Microsoft had invented the automobile? It would not work certain types of gas or it would suddenly stop on the highway for no reason then you would have to find the stop button in order to restart it... If Apple had invented the television... you would have to pay $$$ just to use the airwaves or you would have to pay an extra everytime you would change the channel...
@@PR-fk5yb This is also true, yes.
NTSC actually stands for Never The Same Color
This was explained beautifully; I understood everything he said. Well done!
Wonderful explanation, and the “beam graphics” demonstrated on your CRT really clarifies how the sweep, scan, and interlace produce the raster. It’s amazing how these vestigial technologies spill over to complicate modern methods...
The total time of a frame is enough to draw 525 lines on the screen, but that assumes you are dividing the frame time by the time to draw one horizontal scan line. However you have to also include the horizontal blank interval i.e. the time the beam is off so it can be repositioned at the start of the next scan line, as well as the vertical blank interval, i.e. the time the beam is off so it can be brought back to the top left corner of the picture from the bottom right and does this for each half frame. When those are taken into account, it turns out you only get 480 scan lines total. Horizontally, you can draw 320-350 alternating dark and light vertical lines giving you (in computer monitor terms) about 640-700 pixels on each scanline depending on how good your comb filters are. I know, 4 years late to the party, but there it is.
Never
The
Same
Colour
versus
Perfection
At
Last
Never Twice Same Color
I would prefer the higher refresh rate with ntsc lol
@@LunaWuna
PAL60 gives you PAL at 60 Hz.
@@Katzelle3 including the NTSC resolution
Wrong, increasing NTSC to 625lines would have been a mistake. The goal for adding colour to the signal was to retain compatibility of all broadcasts with all sets, regardless of whether a black and white set or a colour set was receiving either an old black and white or a new colour broadcast. That fancy 15734 number is actually the operating frequency of the horizontal oscillator 15.734KHz which is what causes that farmilar high pitched buzz we hear from the back of an operating set. increasing the number of scan lines would dramatically increase the frequency outside the resonance and tolerance of the oscillator circuitry. This oscillator is local and is timed using sync pulses in the video signal. A 100 line increase would ad 2KHz to the horizontal oscillator and could make it become unstable, not to mention the horizontal oscillator not only draws the raster but also provides the HT for the cathode ray tube through the flyback transformer, which is a central part of the oscillator. the flyback is designed to resonate at the 15.734KHz horizontal frequency for efficiency. If the oscillator becomes unstable you could end up with timing issues and complete loss of HT to the tube if the oscillator collapses, and also the potential for burning up the drive circuitry for the HT supply, since it was all designed to resonate at the horizontal frequency. Sets would struggle and cheap ones would outright fail. It would require modifying the set, or replacing it entirely which is exactly what they were trying to prevent, remember back then a television was not a small investment.
NTSC was a major breakthrough to add color to B & W in the same bandwidth and maintaining compatibility. PAL suffered major problems with flicker. The reason movies could get away with 48 Hz without major issues with flicker was that they were viewed in a dark room, and PAL needed to also be viewed in a low light environment. NTSC at 60 Hz can be viewed in a more normal lighting, but still had issues in daylight. To get beyond flicker, the refresh rate needs to be >75 Hz. I worked in TV/video from 1977 to 2007, at 66yr I am still able to hear and be annoyed by 15,750 Hz.
why the hell is this video 50fps
Yeah, why not 59.94
The PAL standard frame rate is 25 so double that to 50 for modern high frame rate PAL.
My guess is so that its FPS is multiple of the CRT screen he has there, so that no flicker is visible.
Because as he said in europe CRT uses 25FPS so filming it at 30 or 60 would cause problems, but as 25 is a factor of 50 it works
sorry. premature comment.
They could not have made 30 x 625. That would have brought the horizontal frequency to 18750Hz, which is quite a leap from 15750. It would have broken compatibility with existing sets and other equipment. The change from 15750 to ~15734 worked because the analog electronics involved had some, say, "give". They could tolerate some variance up and down from the expected frequencies, but that much of a change would have been tolerated by very few existing sets, if any at all.
Also, even for those sets that would tolerate and display the new signal, most would probably suffer from some instability, and even those that were stable, would need to be serviced to get the new signal to display correctly, because the video signal doesn't contain driving signals for the deflection coils, but just pulses signaling when to return to the starting position to scan a new line or frame. Then, the electronics on the TV set, upon detecing that pulse, internally generate the sawtooth electric currents that actually drive the deflection coils. These are called flyback transformers. Those found on PC monitors with geometry controls can be adjusted pretty widely, but those on regular TV sets are specifically made for one and only one sawtooth wave lenght, which determines line lenght on the screen.
Basically, your +18kHz horizontal sync signal, if accepted at all by an existing TV set not specifically made for it (let's rememeber that the idea was to keep compatibility with older BW sets), would result in a picture that didn't fill the whole screen but left a portion of the right side of the screen completely black, because a new horizontal pulse would arrive before the flyback transformer could have driven the electron beam all the way to the right side of the screen.
Just tweak the Width and HPos potentiometers on the back.
@@jeepien Have you tried it with TV equipment of the time? I'm not saying I did, but it sounds like, if it was as easy as that, they would have done it, right? So, are you sure it would work?
@@radornkeldam No, I haven''t. Although it would in principle, it's quite likely that such a large change would push it outside the range of existing controls. Nothing is easy.
I did have TV equipment back when the NTSC change occurred, and it was completely undetectable on older B&W TV sets. The Vert and Horiz controls needed occasional adjustment anyway, and had no calibration of any kind, so any small change would not be noticed. You just turned the knobs till the picture held still.
@@jeepien Many - if not most - TVs back then used as adjustable coil in like with the yoke to change the width. And they didn't have a whole bunch of adjustment. They also didn't have a horizontal phase adjustment. You could adjust the centering magnets on the tube to some extent.
@@compu85 TV sets had "Horizontal hold" and "Vertical hold" controls. Just knobs, no numbers. You would adjust the horizontal until the picture stopped looking like a bunch of slanted lines and torn up garbage. You would adjust the vertical hold until the picture stopped rolling frames and locked on one stable frame. Once you got it close, the frequencies would lock to the sync pulses in the picture data, and everything would remain stable. A tiny difference between 30 and 29.97 would not be detectable by anyone with an analog TV set.
On the back of the set, through screwdriver sized holes, you would find rarely needed adjustments of Width Vertical position, and Vertical linearity. These were local adjustments unrelated to the signal. They just put the picture in the right place on the screen, and didn't need to change to match the signal.
The editing on this video is remarkable
With colour TV the subcarrier frequency is the reference for line and field frequencies. This is to minimise sub carrier visibility in the way you mention. In generating the sub carrier, the engineers wanted to use simple multiples of an integer reference frequency (a whole number of MHz) and try to get as close as possible to the existing line and field frequencies. The choice dictates the exact line and field frequencies, and they tried to choose a reference and multiples/divisors to get as close to the existing freqs as possible, and settled on 5×7×9/(8×11) MHz. The frequencies are not tightly locked to the 4.5 MHz video bandwidth, there is no need to control this tightly.
The development of NTSC was utter genius and was pushing technology beyond known limits.
Always knew NTSC as "Never Twice the Same Color"... must be my european PALs that taught me this ;-]
NTSC: Never Twice Same Colour
SECAM: Systéme Extraordinaire Contre les Américains
PAL: Perfect At Last
PAL: Pretty Awful Looking
@@gerardjlaw "SECAM: Systéme Extraordinaire Contre les Américains"
That's good!
@@daveholden2711 Not my creation. I heard it from Pete Harris at BBC Engineering Training Department.
Cool graphics. I wonder how you did it.
sane
You can just hook a pc up to the tv, as long you have the cables. PC monitors used to be CRT
of course but what is displayed didn't create itself. I guess After Effects. Whatever program, very nicelly done.
He did a behind the scenes on this
Probably like a powerpoint presentation and a remote on hand or on foot. And yes i'm answering to 10 month old question lol.
'Ashuming'
where?`I didn't spot it :O
DoctorPC 9:50
Andro A Englishmen need speech therapy.
It sounds like he was a Kiwi before the British part of his accent.
Or sightly more aussie. The slurring in 'ashuming' is a classic speech laziness in both.
Excellent history lesson! As a former resident under NTSC, and also wondering how in the world 29.97 ever existed, I found your video very interesting and exciting! I'm exploring the possibilities of video production and editing in post. Thanks. RS.
If they had chosen to increase the line count to 625 instead, then the spectrum of the signal would have changed, adding more high frequencies, making it no longer fit into that 4.5 MHz window.
Perhaps. But the main reason for keeping 525, as many others have already noted here, is because most of the TVs out there were B&W (and there were lots and lots of them), and they could not adopt a standard that suddenly made everyone's TV become useless.
Yes, definitely. But even if they had decided to change the standard more thoroughly, they wouldn't have been able to for the reason I mentioned.
It could have been fitted into that window, but it would have required more aggressive low-pass filtering, which would have resulted in a blurrier picture.
Televisions of the early 1950s were really, REALLY forgiving as far as what they would accept as input. They all had H-hold and V-hold knobs that changed the timing of the signal. Even later TVs with only the V-hold could somewhat display 625 lines by adjusting the V-hold knob.
A 1950s TV could very easily be adjusted to display 625 lines, without losing any of the picture.
The biggest problem would've been that 625 lines would be quite blurry on American TVs. It would still have to fit into the same 6 MHz channel space that was originally designed for 441 lines in the 1930s.
I'm sure the people working on the standard would have used 625 lines if they knew for a fact that all existing TV's could handle it (even if they needed adjustment). The fact that they didn't shows that it wouldn't have worked. Perhaps because it'd be blurry, but I don't see all TV's being that forgiving. Remember that "most TV's will handle it" isn't good enough, you must guarantee that all will.
Another constraint on NTSC television was that the color signal had to be viewable on black and white TVs, which were the vast majority of receivers in use at the time. So they could not change the number of lines. Changing the frame rate by 0.1% was within the tolerance of what the existing receivers could accept. So it wasn't a bad choice, it was a very clever choice that met all constraints.
Far from dumping on the engineers of the 40s and 50s, I admire their ingenuity. Modern digital techniques are much easier and far less constrained by physical and mathematical laws.
Sadly this is one of the problems being early when adopting new technologies.
It can be difficult to tell exactly what you need, how to create something, and so on. This often ends up in you finding out what you should have changed.
But, by then the old systems are already in place and you can't just shut them all off.
How is that sadly in this case? Whoever decided that near-30 fps is enough made a tech that lasted 40-ish years and near no one ever said it's a problem or even acknowledged. On the other hand now we have opened pandora's box where most people are moving toward 60fps while at the same time there are already people who say 90 or 120 or 140+ is the minimum desired level. Leading to tech being deprecated often within a year while we are supposed to save resources and environment.
@@kallemetsahalme5701these are 2 very different things. It isnt exactly the fps that is the problem, but having to be compatible with b&w and make a smooth transition.
It is about getting the technology and not fully understanding it and planning it out that leads to problems. Luckily with tv it is just a debate, but with other things it has costed lives.
@@kallemetsahalme5701
Your point is 100% correct. However, in this case it was a decision of backwards compatibility AND seamless change. Nothing really about frame rate itself. As no one will notice the -0.03
Also are people saying that like 90, 120, 144, etc. is the minimum desirable frame rate?
As I will be honest 60fps is perfectly fine, 120 fps is even better, and 240 fps is incredible.
It depends on application though. Gaming? 120 and above
Watching movies? 30 or 60
Animation? 30 is probably the best
Thank you very much indeed. You were able to provide what you had promised in the beginning: a nice, coherent and concise explanation ...
The problem with 25 fps is that it flickers like hell, specially in CRT monitors. It was impossible not to notice it back then.
Curiously enough, Telefunken developed the PAL-M back in the 70s. It has 60fps (not 59.97) and also features the phase alternating line (aka PAL) that made the European PAL famous for its color fidelity.
The system was only adopted by Brazil and worked pretty well.
To be fair, most European TVs would have compensated this flickering issue by using phosphors with more persistence (the glow lasts longer).
The problem with this, however, is that you would notice the persistent glow a lot more if you were watching a content with high contrast--for example, a helicopter searchlight beaming down from a dark sky, well, you'd notice a trail of glowing phosphors behind the searchlight a lot more with a PAL TV.
As for PC monitors though, the phosphors had even less persistence than an average TV, because they were generally supposed to be run at 70 Hz or higher. That's why running one of those at 50 Hz is just eye hurting!
You must have real trouble watching movies, then, because the cinema screen flashes 48 times per second, less than PAL’s 50 times per second.
I don't know of any theatre that uses CRT projectors or old-school film projectors anymore--at least around where I live--so I'm not sure if that's a big issue anymore since it seems the most common projection tech is based on displays that don't inherently flicker.
I can't really say I've ever noticed a 48 fps flicker on a recent movie night.
Even older movies didn't scan so their was no flicker. Fps in the theater is the whole frame at once. You only have 1 line between frames that interrupts the image. You don't have half of the image being scanned in at once then the other half.
No, that's not right. You cannot show a frame in theatres for a complete 1/24th second, because the film stock had to be pulled in place and then advanced to the next frame. The film transport would cause immense vertical motion blur (for regular 35mm projection). Theatres always used rotating shutters to hide the film transport motion. That was also done with the cameras. To make this rotation smooth, each of the 24 frames was interrupted twice. During one of the interruptions the frame was transported. This resulted in 48Hz for 24 frames :)
Later projectors used higher speeds, such as 72Hz or 96Hz (probably why nobody noticed flickering in the last decades).
I screamed when I started to watch this the first time. I'm older and less prone to screaming over tiny details.... I did write up some number details you seem to have glossed over. The numbers were not changed to the "obvious" numbers for backwards compatibility, a concept digital TV blew out of the water.
There is a very obvious question here, why was the sound subcarrier frequency not modified by 0.01% to 4.50450450450 MHz? That's a story about available electronics parts of the era. Precision frequency sources were all generally multiples of 5 MHz. 4.5 MHz is fairly simple to generate from 5 MHz. From there you need to use clumsy parts to synthesize the various frequencies used in the signal.
To totally unwarrranted levels of precision
5 MHz 63/88 = 3.57954545454545454 MHz, color subcarrier.
Color subcarrier times 4 = 14.31818181818 MHz.
The video was presumed to give 910 pixel times per line 720 of which were visible and the other intervals were part of a complex synchronization process.
14.31818181818MHz / 455 = 2 * 15734.265734265734265734265734266 Hz
Then there are a total of 525 line times, some 45 of which are for special services, retrace, and synchronization signals. Roughly speaking, though, only about 400 or fewer are usually seen on TVs.
15734.265734265734265734265734266 Hz / 525 = 29.97002997002997002997002997003 Hz or about 1 part per million off 29.97 Hz.
In practice banks of dividers off either 14.3181818+ MHz or 28.6363636+ MHz derived from 5.0 MHz oscillators were used for a long time. In the Los Angeles area the 5 MHz oscillators were often derived from cesium frequency standards before people realized they didn't really have to be super accurate after all.
If everything was moved to 60 Hz all that nice arithmetic right up at the start goes to "heck". And they didn't really want to use more difficult frequency generation techniques. After all, WWV transmits at 5.0 MHz not 4.995 MHz. And the FCC had demanded precision at first.
{^_^}
It's a parker framerate.
parker framerate*
@@martinator9480 you're right, I fixed it
@@martinator9480 What was the original?
What superb exposition! This is a complex subject, which has puzzled me for years, and you made it crystal clear. Bravo!
10:46 is almost the Futurama God quote: “when you do things right, people won’t be sure you’ve done anything at all.”
Agree. I noticed that too.
Some people take this as standard for crafting anything in life.
That´s pure Lao-Tze.....right there.
Changing NTSC to 625 lines would have helped PAL video gamers. We got a raw deal until about 1999-2000 when PAL 60Hz games started appearing. PAL games at 50Hz always ran slower and with borders because developers didn't use the extra 100 lines and the games were rarely adjusted for speed at the lower frame rate.
I had a designed-for-PAL video games console in the early '80s. It was made by Philips. I used to love "Race Car"... =;o}
When I see your hair I'm suddenly scared to get old
+Gian990 I serve as a warning of the inevitable passing of time.
standupmaths
(':
It's okay, all that hair you lose from your head will magically regrow all over your body.
First timer here at your channel and love how you explained it (very clearl) and the exactly timed animations on the CRT. Well done! This is an excellent example that a (minimal looking) video like this can be informative, fun to watch without the need of fancy stuff around. Really like it.
Yeah, NTSC is "not the smartest choice," except for the fact that Americans, in essence, INVENTED broadcast television. Yeah, B&W NTSC was finalized in 1941, and NTSC color in 1953, while PAL was finalized in 1962. When NTSC was first invented, nobody had even thought about color at that point. The amazing thing was that color was able to be added without breaking B&W receptions by the installed base of televisions.
So, the lesson is: if you want to do something better, wait for somebody else to figure out the hard bits, and then copy from them, making a few improvements. You get to avoid their mistakes, plus you can use technology that is 20 years more advanced!
Also, there is a problem with changing the horizontal rate. The flyback transformers of older BW tv's could not have handled the higher frequencies without being ruined.
How did movies end up with 23.976 then?
Movies are still 24 fps. But shown through NTSC you would have to make up for the last ≈6 fps to get to ≈30 fps.
With PAL they just sped the film up from 24 to 25 fps, but speeding it up to 30 fps would be too ridiculous.
Therefore they use 4 frames of 24 fps film to create 5 frames of NTSC video in a ridiculously complicated process called the Three-two pull down method. Read more here:
en.wikipedia.org/wiki/Three-two_pull_down
"Just sped up the film" That's a major change in the timing of a film. Great directors and actors pride themselves on good timing. There was no pitch correction (for many years) so the audio was screwed up, too.
2:3 pulldown is quite simple. Europe uses the truly ridiculous 2:2:2:2:2:2:2:2:2:2:2:3 (Euro) pulldown. Read more here:_en.wikipedia.org/wiki/Telecine#Frame_rate_differences
Chris W
well going from 24 to 23.976 is about 0.1% of the speed in difference. It's not good but can be ignored.
PauLtus B It's non-good when the audio starts to slide out of sync as it is 0.1% longer.
Chris W, wow that is a truly ridiculous method, especially regarding the fact that fps will be less critical in the future as linear television slowly fades out. I've never actually heard of this method as it seems to be quite new it but it does make sense.
One of the most interesting presentation methods I have ever seen on youtube :D Good job!
1:10 well, not an infinite amount of image. That would require an infinite resolution and probably an infinite amount of money. ...and that's kinda a problem.
and an infinite amount of time
Did you, a Brit, just write colour without the u? :o
But including the u, there are six symbols, allowing you to make a colour rainbow, inside the word 'colour'!
How dare you write colour without the u?!
He's not a Brit.
+russ18uk really?
+russ18uk but he does use British english
Well, to be fair he was speaking about the American standard at that point.
He is actually an Australian (but living in the UK, though).
Thing is, NTSC never used "line-by-line phase reversal", which was at the heart of PAL.
@Maxx Fleischer You must be referring to the fact that the phase of the colour burst signal is 180°.
So, what was the point of fiddling around with the numbers?
Wow, this was really well done! Kudos Matt, I've enjoyed some of your stuff before and watched this video after export my own TH-cam video at 29.97 fps and wondering why, haha!
The only reason why 4.5 Mhz was hard set and unchangeable was because of the government over regulating things. 4.5045 Mhz would have made the math come out perfectly, but because the government set a hard number to ensure signals would have plenty of room not to interfere, that wasn't permissible. Just an extra .0045 Mhz, would have solved the problem, a hardly even noticeable dip into the 1.5 Mhz buffer.
This is why government legislating regulations is a bad idea! Congress doesn't make it easy to adjust outdated laws, and no one wants to spend the insane amount of lobbying money needed to make what would be a reasonable change.
And now, instead of being able to set frequency the easy way using the AC frequency tons of extra engineering had to go in to set the frequency manually. Making the TVs more expensive to make.
I couldn't focus the whole video, I was too busy watching the red LED reflection on the monitor !
+Matthieu Sontag I nearly re-filmed with some tape over it!
and so, Europe saw North America and said, "what a mess!"... so true even to this day.
(cough cough presidential election cough cough)
Brexit?
Well, yes and no. The NTSC compatible color standard was developed by RCA before transistors were common. and was developed on top of the existing monochrome system. When PAL was developed, it was years later, they had better technology to work with and it was a clean slate. There was an NTSC color standard that was not backwards compatible. The CBS Field Sequential Color system was released in the early 1950s and used a spinning color filter wheel in front of the tube. That system was quickly scrapped, but its technology was used elsewhere.
Look here on TH-cam for videos of early color videotape recording from the 1950s. The RCA TK-41 cameras actually made a nice picture... and no transistors!
It's more like the US looking at the UK and Europe and saying "how can we fuck this up worse?"
Your bigotry is showing... PAL came years after NTSC. Learn to read.
Very interesting video.
One thing which weighted on the reason they did not want to change the number of lines:
Back then. things were built to last (at least, to last much more than now) and the rate of change/progress was much lower.
They had to respect all the people that were already owning a B&W TV, and that would not buy a color set before many years later.
This meant the new signal had to be compatible. The 525 lines had to be respected. They could not simply say:
"Hey, all of you with B&W TV owners, from now on, our TV signals will have too many lines for your TV sets, so throw them in the garbage and buy new ones!"
Heck, they couldn't even change the number of lines lines to 524 or 526, either. That would mean that the slightly-too-small image (524 lines) would not reach physical line 525, the "half a line of zapping back to to of screen" signal would be confused with the the data for line 525 (making that line look like ugly junk), and the line 1 data of the next image would be interpreted as "jump back signal) (and skipped), and the all with a half-line delay desynch. Ouch. So you'd get 2 overlapped images offset by half the width of the screen, and that also slowly scroll up the screen every 17.5 seconds. Wow. Talk about looking at pure garbage! Same for 526 lines, but scrolling down instead. Yeepee.
Basically, all the stores TV inventories would be ruined, or they warn well in advance and B&W TV sales would drop drastically in the couple years before the swap. You can easily see the huge uproar that that would have caused.
Nowadays however, things are different, We're used to "use and throw away" and a much faster pace of change. When TV went digital, all analog TV owner got told (YEARS in advance): either buy a new TV with digital capability, or buy a 100$ separate special digital-to-analog TV Tuner & converter, that will convert the digital signals back into analog for your old TV. For years people bought TVs that had both digital and analog inside, until the actual signal swap which forced only those relatively few with really old TVs to either buy a new one or buy the special tuner. all in all a relatively painless migration. (well, that was when I stopped using my 10 years old TV lol to watch TV, only for my playstation and video cassettes, until the internet got me too).
Some grumblings, but the transition went without too much of a itch. Even then, it took years and was planned for a very long time.
Still, a 100$ tuner is still costly, and such a tuner/converter is a relatively simple piece of electronics. But much less than a brand new TV.
But that kind of thing would have been impossible to think of back then. Can you imagine taking a 625 lines image, and having a "tuner re-parser" that rebuilds a 525 frame image "just for your old B&W TV". Skipping some lines? That thing would have need of a special "buffer" and been quite complex and would have overall cost much more proportionately to buying a new TV anyway. Many old TVs had straight out antennas jutting directly out of them, without "cable input". Because that was entirely before Cable TV! In fact, a TV back then looked more like a radio that also has a screen!
So, there was no capability to "add a tuner". People also had the tendency to use their TV set not for a mere 5 to 10 years, but fully expected it to last at least 20 or more. Same as refrigerators, truly: refrigerators of that era didn't have all the bells and whistles, but those things are seemingly invincible and eternal, while today's refrigerators will last you about 8 years. If you're lucky. so they couldn't just
Also, If a device able to grab in radio waves and convert them back to the old format for your old TV existed, that would flow the airwaves with way too much interference, too. And keeping separate frequency spans for B&W and for color would also have been wasteful. There was just no nice little cable input for a converter to be designed to attach to the TV.
So it was the signal itself that just *had* to be fully compatible.
Changing the number of lines was completely impossible for economical reasons, while very slightly changing the frequency was in fact possible, and the old tvs would still work ok with the new airwave signal.
It's the initial 525 lines which was a bad choice. Or the assigning of a 4.5 Mhz wide airwave band. But to their defense it is extremely hard to predict in advance how tech will need to change. And I'm quite sure there was a strong reason why "525" was the number of lines initially chosen.
NTSC = Never The Same Colo(u)r ;) I've often wondered why US TV looks so smeared and washed out, I guess the 525 lines is a big part of it, though I think I read that the colo(u)r encoding is also pretty weak. Thankfully I suppose much of that is ancient history already.
All hail digital.
Why you say "colo(u)r", and not "color"?
Because it's properly spelt colour.
I learned (back in school and talking with a BBC engineer) that NTSC was sometimes called "Never Twice the Same Colour", due to its phase-encoded colour being the same on every line; the colour phase signal could get offset on the radio transmission path to consumer TVs. Which is why there was Hue correction knob on NTSC TV sets. In the UK (and other places) we used the derivative PAL ("Picture At Last") system, which switched the colour phase encoding 180-degrees on alternate lines; so transmission phase errors could be cancelled in the TV receiver (I think in a big glass block) - hence the name Phase Alternate Line. I think.
"Thankfully I suppose much of that is ancient history already." Apparently not, both you bastards keep talking about these things in the present tense. I truly feel sorry for Europeans if you guys are still watching TV at the old PAL resolution. I have 4k TV none of this applies to me.
NTSC in the 50s: tweak this framerate down a notch for interlanced backwards compat
Tech corps in the 21st century: yeah so we're gonna progressively scan everything at multiples of 60Hz; suck it
144Hz monitor manufacturers: hold my beer
165Hz monitor manufacturers: no, hold _my_ beer
The thing is, this was already a thing in the CRT era. You had 70 Hz, 72 Hz, 75 Hz, 85 Hz, 100 Hz and so on.
Matt, I hear the clicking of a remote for that powerpoint. You didn't fool me.
+Lucy Tycho I might have a cheeky foot pedal…
2:45 So THAT'S why running the vacuum always messed with the TV in the pre-LCD years! I've had that question since before I could just Google it, and forgot it by the time I could.
And now that I think of it, this makes me want to build a new alarm clock with an internal oscillator to get those likely seconds a year, from using the AC signal for timing, back.
Linus where are you
why would he be here?
meloD30 Linus posted on twitter
NTSC:
Not The Smartest Choice
Never Twice the Same Colour
No Television Shows Colour
Never Thought Someone'd Care
or Never The Same Colour
And (the French) SECAM stands for "Something Entirely Contrary to the AMericans."
Not Tested Since Christ
+standupmaths
A thought about increasing Lines to 625. 2 Main points :-
(1)
To increase the lines to 625 while keeping the framerate, would mean increasing the horzontal scanning frequency, which compared to the picture bandwidth means 'stretching out' the beam, 'going faster' for shorter time for each line. This will increase blur on the picture horizontally as the 4.5mhz bandwidth limits the speed can switch from bright to dark, sharp edges in brightness will become more gradients etc.
(2)
In any case, substantial change in horizonal frequency would then loose compatibility with existing TVs that try to lock onto the NTSC horizontal frequency from the mono-standard days, they may use a local oscillator with a simple phase-lock-loop and just not designed to "stretch that far" to a substantive horizontal frequency change. Let alone the various 'horizontal size' adjusters might need fiddling to widen out picture and soforth.
The '29.97 hack' was a small enough change to remain compatible with existing mono TV sets....
Does that make sense?
Nö
25 Parker squared
I like that you put those number figures right IN the video ON your old TV in there, instead of just simulating it; we can see how genuine that is!
Thank God for progressive scan.
Interlacing is a compromise, and has advantages (and disadvantages) of both ways. You get twice the frame rate, and twice the resolution, just not both at the same time. Interlacing makes movement look smoother. They could've gone with progressive scan from the start, but chose interlacing deliberately.
greenaum colour was a compromise, then stereo sound...
You don't understand a thing. When the American standard was created, it was a frame rate of exactly 60 Hz, and a horizontal rate of exactly 15,750. There were 10s of millions of receivers in North America, and in order to get approved, the NTSC came up with a way of shoe-horning a color sub-carrier and information, so that all the B&W televisions would still function and new color tvs would also work. The engineers brilliantly made it work, unlike the U. K. Europe and the other PAL countries, where old receivers were obsolete and they were years later than North America. This was not a whim, old tvs worked as always and new color sets brought color to the home. Absolutely brilliant!
cmon brother hold my hand and lets both embrace the fact that we need to just shave our heads..
I'm getting there too.... hold me
dye it
Just do it. Each day you wait is going to make the cringe that much worse. Shave your head, grow some facial hair, and you'll look so much better.
can we also hold dicks?
Dude, do it. Chicks love rubbing a smooth head ;)
Never have I ever got a better lesson in maths, electrical engineering, electronics, history and that too, combined.
If teachers explained this way, the world would have been a different place.
I didn't watch the end of the video. I belong to the other 70%
What? I never lie!
I never lie! And I ESPECIALLY wasn't the person who ate the last cookie!
All Cretans are liars ... and all cretins are sincere. Which one do you prefer ... said the philosophy geek ... not, the 6th century BC Greek, Epimenides.
P.S. Yeah. My command in English grammar sucks. I have prepared a standard issue Luger for the Grazis
When I wrote my last comment I thought it was a paradox. But if you look closely, it can simply be either a true or false sentence. What I really wanted to say is:
This sentence is true.
***** Both are paradoxes. Though yours is more widely accepted, so to speak.
I hated how a lot of video games in the 80's/90's had black borders on them. Because they were coded at 525 lines, and our TV's had 625. The just filled those 100 extra lines with blackness.
Patreon doesn't sound so bad...problem is I don't really have anything to donate so I'll leave a comment here to let you know I'm one of your people who stuck around.
+Royce Trofel Dotado Thanks! I appreciate your sticking around.
hi
Wow, so glad I paid attention to the end of this video and got that sneak peek!