CD / The Horrors of the Alpha Channel
ฝัง
- เผยแพร่เมื่อ 21 ต.ค. 2022
- Please consider supporting my videos on Patreon:
/ captaindisillusion
CD /
• Intro - • CD / Intro
• Aspect Ratio - • CD / Aspect Ratio
• Frame Rate - • CD / Frame Rate
• Resolution - • CD / Resolution
• Interlacing - • Video
• Color - • CD / Color
@AmiYamato sighting at 1:46! - บันเทิง
When I and the other creators of PNG were defining the way alpha channels are stored, we generally all agreed that the only benefit of premultiplication was faster compositing. File formats designed for long-term information storage should contain *all* the information, not just what shows up in the final image, and premultiplication involves irreversible information loss. So technically, if a PNG image is premultiplied, it is not a compilant PNG (though that doesn't prevent software from producing them anyway). But that's why there's no metadata to indicate premultiplication in a PNG--it's strictly not allowed.
how has no one noticed an internet godfather in the comments lol
wait... it's actually him!
OH MY GOD you're a legend!
the idea of metadata indicating premultiplication without any other changes to the format definitely sounds... off. a png file claiming to be premultiplied but nonetheless containing color data in pixels with no alpha sounds like a relatively tricky invalid state to deal with
@@ZweiSpeedrunsor describing a way to encode emissive materials that don't completely obscure their background, like flames or plasma
I didn’t wake up knowing whiskers in silver face paint bothered me, but here we are. Fantastic video as always!
It's beautiful how the whiskers flying off distracts from any (tiny) inconsistencies in the composite.
Wait, it's facepaint?? I thought that was natural. TIL.
Fascinating.
Read this comment almost immediately after listening to the 'Banned Words' episode of NDQ.
One funky looking beard
The paint is actually on the upper half of his face.
What I took away from this is that I can totally put VFX Generalist on my CV
lmfao
Ahahaha yeah
Way ahead of you
What I took away is that common tools for the masses don't take advantage of what's possible. But why?
Was cv
0:01 The reference, for all the Gen Z kids, is to an old Saturday Night Live skit from the late 80s called "Pumping Up with Hans & Franz". It featured two men with heavy Austrian accents named Hans and Franz, who would be overly enthusiastic about getting you to exercise and would mock you for not being as strong and physically fit as them. The characters and skit were a parody of Arnold Schwarzenegger's appearance in the documentary "Pumping Iron".
Honestly more younger people will get the reference from Team Four Star’s Dragonball Z Abridged
so that's what TFS were referencing...
i thought it was a dashiexp reference.. i really am too young to get the reference huh
@@sillycatgirlnya I don't know. How old are you, kid? I don't even know what dashiexp is.
@@Channel9001 i’m 17
Okay I need another full hour of CD sarcastically suggesting fake buzzword-y AI techniques.
Perhaps we can have an AI generate it.
@The wock I just got rick rolled with potatoes. Awesome.
I'm not sure they are fake, half of what he says is real, the other half I don't know, so maybe.
@cock Sadly.. This too is AI these days. Just randomly posting a horoscope like enigmatic statement in the hopes of rickrolling some unsupecting user to "watch this clip you have been looking for..." jeez.. A bot. So 2021
The Generative Adversarial Network part is real, convergence and diffusion are also real but are tied together incorrectly. The rest I'm not sure
That was an incredibly convincing George Lucas impression!
Awesome video as always.
agreed
Knocked his beard clean off.
yes
Yes no-one ever gets the silver beard quite right...
Didn't expect to see you around here, another legend!
Love how the Captain chose the pronunciation of "GIF" guaranteed to infuriate everyone
Or to infuriate no one. Now both sides can laugh at the funny pronunciation. Just a genius like CD can come up with such a brilliant move
Edit: spelling
2:05 "giyef"
He didn't stick with it though; switching to gif and not jiff
The real debate should be on "p-n-g" vs "punnghh"
Didn't PBS Idea Channel standardize that pronunciation years ago? I've been saying zhaif ever since, at least in my mind, since it surprisingly never comes up conversationally.
6:50 I love how here he starts to use terms that I don't think most of us understand so you won't expect the DEEZ NUTZ at the end. Simply Incredible.
Its even funnier when you do understand the terms.
You know it, fam.
The end was perfectly cut off for the best joke ever made and I love you for that Captain.
CD's nuts
@@arcturuslight_ It's almost invisible
Deez
Yeah I'm not proud of how hard I laughed at it.
How do you guys watch this so fast
I was one of the two guys who talked the TIFF standard committee into a way to add alpha to TIFF files way back in the early 90s, and I have had to explain premultiplied alpha over and over again for the last 30 years.
The only problem with this video is that you didn't make in 1990 so I could have just shown it to people all of those times.
I'm glad you get the part about emissive surfaces in there, that's a fine point many people don't get. The reflection on window glass or the color of a candle flame does not hide what is behind it, so the transparent color value has to be able to be larger than the alpha value.
Thank you for your service and hard work!
What's the work flow?
@Jack Salzman Seems you did not understand the issue. There are things that can only be correctly stored in a pre-multiplied form (e.g. glowing transparent things like candle flames). By not supporting pre-multiplied and silently converting everything into that 4-channel format you propose, many software packages destroy those images.
If that's true, I commend you. Cheers!
@Jack Salzman That's what "straight alpha" is, and it does not fix the issue.
Just wait until they introduce the Beta channel
gamma channel
Delta, Omega, and Sigma channels when
How about the full release channel
OwO
what purpose would it even serve at that point
This is actually the most marvellous series on the entire internet, nothing has come close to making me so interested in a topic I know nothing about in such a quick time!!
I agree this cats on another level and actually breaks it all down going into the rabbit hole like this.
Too bad he don’t post as often but still great content everytime he post
same.
i trust his content as an outsider to vfx.
education disguised as entertainment
When CD uploads, I automatically go to it, because it's like a solar eclipse. Once in a while and you can't miss it
You beat me to this comment by two minutes. Though the solar eclipse thing was something I wouldnt have thought to add. So I'm glad I got beaten to the punch on this one.
*looks at the video recommendation from 3 years ago*
yea...sure.
It's as rare as an eclipse but luckily as timeless as the colosseum.
Same
Lol
He took so long to upload this because he had to grow that George Lucas beard
How dare you use Hans and Frans to call me old
He really pumped me down with that
Dinosaur.
What's Hans and Frans?
-kid from 2007 (I'm sorry)
Hear me now, listen to me tomorrow, and believe me next week!
ou
2:52 the zeitgeist returns
Ha, didn't notice that until now
He doesn’t have a headache this time
I started watching this channel about 5 years ago and it inspired me to start messing with 3d. Yesterday i got into nyu for 3d animation. Keep being cool and inspiring people
That's awesome dude!
Cap, this is another perfect example of composing humour and education. Please make a vfx courses somewhere, i'd pay any money to be your student!
I'd pay for that course!
true that
This was the best explanation of mults.
His Patreon has a tutorial tier, not exactly a course by any means but yeah.
Не мечтай артем
The Captain is a true legend of TH-cam. He's been around forever, makes nothing but quality content, and has never sold out.
_And_ he avoided the "gamergate" idiocy when damn near every other youtuber in his lane became raving lunatic reactionaries.
He did sell out to knives once
Is selling out not life's goal? I mean, Richard Branson looks so sad on his own island. (the other one, not GB)
He is a true hero
@@User0000000000000004 There is no goal to life except the one you decide for yourself. It's more of a sandbox than a Minecraft Anarchy server.
I worked in a graphic arts lab that made alpha channels by cutting red lith film with an Xacto knife around the image, shooting a film negative with registration marks of it, then shooting 3 color films using screens with rotated grids of the original and taping them all together on a light table, just to change the background on a still image. 45 years ago.
That one second of video from 4:11 to 4:12 was absolute perfection and I appreciate the effort that went into something I could have blinked and missed
Haha
Had to replay like five times to see it though cD
I've never been more confused and entertained at the same time. While I had a vague understanding of what you were talking about, it only made me realize how much I didn't know. BUT, I loved the video. Will watch it on loop until my brain gets it.
I was just glad to learn why images with transparent backgrounds always seem to have ugly pixelated edges when I put them over other pictures
Same. I was like… idk what’s going on, but it’s cool
I didn't get a thing either... guess I'm not the target audience for this.
it is really simple but the way its explained makes it look very complex and alien so don't worry
@@NoVIcE_Source Agree. I didn't understood the problem at all just after watching the video, than I read a few comment and found way better explanations and it got simple and crystal clear in a few minutes.
It's always heartwarming to watch an expert of a field do such in-depth investigation on areas newbies and even intermediate professionals wouldn't know anything about. Thanks CD.
@beyond your imagination hello bot account, consider not living
fr I've never been taught what the hell a premultiply is and now I pretty much understand the practical solution to dealing with them. I'm just going to stick with movs
it’s more od a sarcastical inside-humour niche for experts than educational or explanatory for beginners, gotta love it. CD is one of a kind category of humor, he makes me laugh more than any modern stand up comedian, he is always right on spot. the more you know on the subject, the more funny it gets
@cock njkkoio
Man this was so complicated yet interesting to watch at the same time! Like a rocket scientist explaining rocket science problems to his friends.
I understood almost nothing of what he spoke about, but can't wait to watch it again.
my artistic vision is to skip the chroma key and leave the green background on the explosion
One of the cooler things CD does is the 5:55 mark when he mentions resolution and makes a fun little chime and graphic to reference his other Resolution video. Simple, harmless, and continues his train of thought. Great vid as always
It's also synced with the info card appearing, at least on desktop!
@@4P5MC can confirm it is also on mobile
I came here for this comment. So slick.
@@4P5MC Let's hope it stays that way for a long time without youtube messing it up somehow.
Such a cool little detail. Feels like something's been added to my inventory in a game or something, but completely unobtrusive
Since this wasn't covered in a video, a quick rant about file formats.
Sharing transparent video for collaboration sucks! There are some formats (QuickTime Animation, ProRes 4444) that are widely supported, but the file-sizes end up massive, sometimes into hundreds of gigabytes if your video is a few minutes long. H265 can have alpha, but H265 with alpha is supported pretty much nowhere.
WebMs support alpha, but aren't supported in most editing software either. Programs such as VEGAS Pro don't support it at all, and Premiere/AE from the Adobe suite require a special 3rd party plugin that performs poorly due to no good hw acceleration for VP8/9.
The best solution is usually to render out two separate videos, one of the video itself, and another of the luma/track matte, but this is also often a pain to work with. Usually you'd end up importing the video, setting up the matte, and then precomping the video, or something along those lines.
If the industry put more effort into supporting and using open formats, we'd have way prettier workflows here, but unfortunately that's not where the money's at.
@The wock The intro to your video looks like you just gave up and used a black background instead of transparency lmao
@@MLGaeming it's a bot spamming the link. I on the other hand appreciate the pain of having to send and receive frail hard drives from VFX artists containing Huge ProRes files for a single shoot.
@@xmlthegreat I wish the bots would spam their videos in my mail as hard drives full of ProRes footage.
Working with "image sequences" makes me feel like a caveman
@@quaternaryyy Image sequences go in the same bucket as ProRes - the filesizes are massive. But in addition to that, the editing performance of image sequences is way worse.
That first joke was immaculate
Not something I expected a reference to.
What is it from?
@@ahmetozefe An SNL skit from the 80s by the name of "Pumpin' Up with Hans and Franz"
@@LucGendrot
"WARE GOING TO PUMP YOU UP"
( in my best Arnold Schwarzenegger voice )
1:16 nice touch with the beard blowing off his face. The little stuff like that makes re-watching re-warding.
I always like to be as transparent as possible.
AMI!! I thought that was you in the video!
I have used VFX software for over 10 years without knowing what premult means! Great video.
The CD / series is one of my favorite video series of all time! Definitely my favorite videos on your channel.
Great Work as always! You can really see how much work you put into these videos! Love your Videos!
HE’S BACK
And so are you!
@The wock L
You and the Captain need to collaborate. I don't care about what, you two just need to make some kind of thing together. Maybe have him do the VFX on one of your bargain bin movie ideas.
Austin and Captain Disillusion together for one project. The internet will go crazy.
@The wock i won't! :D
It's a bummer that we only get 8 to 10 CD videos per year, but they are all top notch. Well done, Captain!
10 to 8 a year? I wish... this was only his 2nd this year.
Maybe the rate will increase, now that there are two of him
@@henriksundt7148 but wasnt the dupe improperly made? might cause quality drop...
@@soundscape26 I was thinking of the golden years of Captain Disillusion, back in the day. Now, you're right. He pumps them out so rarely but they are always of very high production value. Hopefully his good for nothing clone can pitch in and help out fer cryin out loud!
Its a blessing we have the chance to see them all, and for free!! not a bummer
This video totally pumped me up! You gained a subscriber, great stuff!
I don’t have any ability to apply what you teach, yet I find myself here every time a video is uploaded. You are so naturally hilarious and so good at what you do and explain it in a way that I get a lot of it…just blows my mind.
Wow, how'd the Captain get George Lucas on the show? Amazing insights too, the Director of The Phantom Menace is still as visionary as ever
W
That was really George Lucas. Unfortunately, all the Captain Disillusion that we saw in this video was AI rendered. It's been like that for a few years now, since he was absorbed into his computer. You know, like in the documentary "Tron".
CD / RLM corssover when
Also impressed he got Hans und Franz as well, really nailing the relevant pop culture crowd here
Cap gives off big "was born a century too early" energy. Dude is so ahead of the curve. Just something as simple as the effect plugging the Resolution video near the end. That's brilliant 👏
Admittedly, he's done that in all of his CD/ videos
idk i think that even though he's way too clever for almost all of the tools and media we have that because of the tech. singularity he was born in the perfect time to show the most of his skill before there is no need or want for it
In defense of everyone else's editing... 0:16
Go back to his first video 15 years ago- its the exact same format he uses right now. I have no idea how but he has literally always been ahead of the curve
Two videos in two months. What a time to -be alive- be subscribed.
Also, making that silver beard for small part of single shot. I can feel the cinematographic effort.
Love the example of "visionary filmmakers", much like "visionary tech entrepreneurs" they had the drive, dedication, and brilliance to, uh, to tell their employees to figure out a better method, faster, and make it good... And that's why they deserve all the profit, fame, and opportunities, cause they took the initiative to... Tell other people to do it for them... Groundbreaking 😍
This topic was way more complex than I thought! It's nice knowing there's still good content coming out of TH-cam.
Ikr like im learning much and still dumb af
There is always good content coming out of TH-cam.. unless you're left wing and get the attention of right wing trolls who mass flag perfectly good content as inappropriate. Of course TH-cam responds to this appropriately.. if by "appropriately" you mean letting an AI review the content and ignore all pleas from creators and their fans to have a human look at it and see that the trolls are lying... Honestly, I wish there was another decent, free streaming service. It'll happen eventually and I'll run screaming from this horrible site.
The effect at 5:55 was so smooth and integrated perfectly with the card appearing in the video UI! I watched it like six times it's so pretty
Doesn't work on mobile but it's cool.
@@11equalsfish it does, but only in portrait? I really don't get TH-cam's decisions.
I got it in iOS horizontal native app
I was absolutely flabbergasted by it.
I have an android but worked in both portrait and landscape now.
I didn't used to before but after new update it does in both
Its incredible how CD’s popularity never drops. Been here for years, will be here for years to come
What an awesome video. I was throughly entertained and didn’t understand one word that was said!
2:04 Finally a youtuber that can say GIF properly
Man, I could listen to Captain D explain things I don't understand for HOURS. He should make "ASMR explaining all the functions of every Adobe setting to relax/study to".
You videos are amazing. Thank you for the likely hundreds of hours you spend making them.
Everything about this channel is perfectly executed and fun, please god never stop making content
I don’t normally comment, but I wanted to say I can see the effort you put into your craft. This is gorgeous, funny, and extremely educational without feeling boring any step of the way through. This is art.
Yes art, but more than that, it's what education should be, so more than art, I'd say it's educational.
Well Said. and thanks Capitan, always worth the wait.
Agreed
@@AdamLemmo Artducational
Ah, the old well-used "I dont normally comment" comment. Anyone that starts their comment off with that...has "commented a lot"...probably too much.
I literally just taught my AE students about Alpha channels and Mattes. I'll be showing this video to them from now on for this lecture!
😱love your videos!
@@harrispinkham and I love you!
I'd been aware of your content for a long while but this extremely tightly edited, tightly written and hilarious video is what made me subscribe.
I went to school to learn computer animation and computer graphics and yet somehow CD you still teach me new things about my craft in every video! Thanks for that!
I've been doing computer graphics and making alpha masks since I was a kid. I never knew about the ignore pre multiply trick for luma overlays. My mind is blown. Proof that even when you feel like you're an expert there's still a lot to learn.
Me too. It was about 15 years ago since I last played with it, but I had no idea.
If you feel like an expert... you probably arent ;)
3:05 The premultiplication monster was legitimately scary. It’s a perfect representation of how I feel dealing with alpha matte settings 😟
This is one of the most fun and entertaining videos I've seen in a *while*, and its about alpha in compositing and the importance of premultiplication. CD over here putting in the work lol.
Fabulous video
Best production on TH-cam
Cheers Captain, it's all become clear now.
Love the double multiplying selfie 😉
It always amazes me how much effort you put into these. Whenever I think something is pretty basic, you somehow find ways to explain it completely differently and more in depth than I could ever expect. Always learning from you man
didnt expect to see u here, nilered who didnt go to school
I mean just look at his face paint, That effort alone is to be applauded
Wow, it's the real MrGreen
@@satyris410 it's so realistic, too! i almost believe the top half of his face is fleshy
Yeah yeah checkmarks made this exact comment years ago under his other videos and years later here you are today, parroting the reason were all watching this while thinking you've acknowledged something special. Would it hurt to just say "great video"
The meltdown CD had about premultiplication gone wrong really makes me want to see a video where he reviews his older videos.
He has his old series where he reviews other people's videos. He should definitely do some on his own videos.
Amazing editing, your content deserves more attention!
You're creating at such a high level that I forget I'm not watching PBS or old school Discovery channel. This is some of the best content to ever come out of TH-cam. You're the VFX Bill Nye, except better.
Yes this video is only about 7 minutes long, but the density of jokes is so high it's still so much better than your average 20 minute TH-cam video the algorithm feeds you.
It honestly felt like half that! So entertaining
5:35 "Boring, all straight, alpha world" sounds like an Andrew Tate alternate universe.
OH MY GOD
This is the best comment on this platform
I haven't seen your videos in a long time! And i love that your still here when i came back
We really do need more videos. Some of us are huge fans look forward to your videos.
6:57 ...nuts
This is a master class on how to make a mundane topic entertaining, funny, scary, hilarious, and informative.
If i had seen this video earlier, it would have been so nice. Thank you CD for making this video. Keep making these VFX basics videos please. ❤️
This video was INCREDIBLY helpful for me.
Many thanks for explaining ❤
The quality of Captain D's videos are incredible. The acting is getting better and better and the visuals are on point like always
Yeah, Captain Deez n-
he does dat in every CD vid..
Yet he still refuses to do an episode on the Apollo Moon landing hoax.
I'll always love the amount of polish put into these videos, where every lil piece of text or infographic gets some subtle, yet engaging motion and sound effects! Keep up the great work Captain D! AI will (hopefully) never replace you!
@beyond your imagination clearly, you own an air fryer.
If everybody reports this, it may be deleted
I love your content because I have no idea what you are talking about, yet I feel smarter after every video. Thanks also you are very funny
Got so pumped up by this video that I liked & subscribed on my way to the gym.
As an amateur VFX generalist, this might be the first CD/ video that I learned a significant amount from alongside being entertained. I had never heard of premultiplication.
Generalists of the world untie
untie indeed
At 4:06 one of the filter things is “furry” ☠️
Hey thanks for the video, awesome as always.
This is most entertaining video I watched about such confusing topic. Thank you!
It always amazes me the attention to detail of our Captain!
Small things like the "Resolution" joke, just to do a segway for a previous video.
And animating the word to colapse into the corner where the notification will appear...
Brilliant!!!
Much love to you and everyone that is part of this wonderful channel!!
yeah, I liked that too
I kind of wish "resolution and resolution" was a joke. People keep confusing image detail (e.g. pixel count) and image scale (e.g. field of view or pixels per inch). A grand example is "pixels per degree" which literally cannot be a single scalar for a 2D image (larger than three pixels - total, not across).
This guy is one of the OGs of TH-cam. Every time he drops a video I immediately stop what I'm doing and consume it!
Hey man i grew up watching your videos and now i am working full time in 3D, VFX as well as motion graphics so yeah you should make more. As well i am still watching them
Wow... respect++ for both of you guys.
3:15 is how I feel whenever I attempt even the most basic video editing.
Every time I see a CD upload, it feels like it’s been so long since the last one. But then I see the incredible effort and production value and it always delivers!
1:06 Okay, how in the world did you do that transition. You're a true magician.
I was thoroughly impressed with it too.
So seamless
With how few frames are actually doing the hard work of that transition it doesn't seem to be that difficult to hand-edit frame by frame
Wonderful video, Captain
i've been dealing with alpha channel multiplications for so long. THEY ARE THE BANE OF MY EXISTENCE!!
I've been reading about the PNG file format recently. PNG files CAN save any information you want in them! It would take almost no effort to just add the text "This image has premultiplied alpha!" inside of the PNG. The only issue is that this needs to be standardized by someone. So, please ask your nearby World Wide Web Consortium to do so.
You can add custom metadata fields
The problem isn't adding the data. The problem is to get software to recognize it and handle it correctly.
@@a4d9 that is the joke
@@abefaerber7994 I didn't read that as a joke.
@@a4d9 you are free to your own interpretation, i suppose
2:42 throwing shade 💀
thats the most soothing and heartwarming "i gotchu" ive ever seen. I luv u cap
This video was watched just in time to PUMP 👏 ME UP!
Love it! Great video, too, btw...but the intro was my favorite part.
This video almost covered all the horror issues with alpha channels, but missed the true terror of a linear color workflow where the software saves out the RGB channels in linear, but the alpha still has a 2.2 gamma applied to it. Let me tell you about the fun process of setting up an AE comp to split out the alpha, apply a 0.454545 gamma correction to it, then recombine it with the RGB, for EACH clip you need to import. ARRRRRGH!!!
I feel you. There's so many possible combinations of linear vs gamma + premultiplied vs straight alpha... tons of ways to get things completely wrong, yay! :S
OH F-- I FORGOT ABOUT LINEAR
Sometimes I wish I understood what any of this stuff meant
But then after seeing all this anger, maybe my oblivious ass should stay out of it lol
seem you seem to have fallen to the misconception that editing is work
@@kartoffelbrei8090 I seem I seem to have found the dumbest comment in this thread.
Captain D as George Lucas is something I never knew I wanted
1:25 "... only instead of film, it's math, and instead of optical printing, it's math." I just wanted to point out that I find this joke very funny. Thank you.
Vou have mad, mad edition skills, congratulations!
"diffusion converge reparametrised strategic equilibria in an architecture matrix of these" needs to be the title of the next video
5:48 that made me laugh way more than it should’ve. captain didn’t even miss a beat after
Bro your videos are INSANELY amazing.
Im damn glad you DID make that reference because I completely forgot about it until you did, was like scratching an itch
Hans and Franz are timeless! Thanks for the callback!
The one part of the video I got!
1:46 This visual joke brought back nightmares long buried
Great video. Thank you CD!
It’s amazing how you showing us why we need premult node (or process) during the compositing by visually. I remember the day I took a whole time to understand this logic via all the documents. Thanks❤❤❤