Intro to Chroma: From RGB to Component Video
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- Опубліковано 16 жов 2024
- How does Luma relate to Chroma? How does RGB relate to Y'PbPr? How do B'-Y' and R'-Y' form PbPr?
Previous videos in this series -
Analog Luma - A History and Explanation of Video - • Analog Luma - A Histor...
What is 525-Line Analog Video? - • What is 525-Line Analo...
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Anders Enger Jensen - / @andersengerjensen
#chroma #video #analog
This is by FAR the best explanation I’ve ever seen for YPbPr. Your videos are always excellent. Keep up the good work!
Thanks!
@@DisplacedGamers Hey man when are those videos gonna be made on composite video and s-video?
Edit: I really wanna see more videos about analog video bud:D
Thanks for this visual representation on how component video works. 15 or so years ago I discovered that "Green is not transmitted, the TV figured out what is green on its own" and I was blown away. I was also puzzled as to "why?" Why go through all of this craziness? My thoughts were that they could just send real RGB with sync combined somehow, using the same amount of cables. In the end it doesn't matter much as component video is pretty much indistinguishable to the eyeball. My brain, however, does not enjoy the fact that something is missing, or that some colors get less resolution than the others. Yes, my brain hates the Bayer pattern as well.
Yes, that pattern is ugly as not only is it deliberately "off" to make signal checking easier, but also because RYB and not RGB are the true primaries. But technology is simply going along with the species that uses it.
Google user I was speaking from an aesthetic perspective.
Red
Orange
Yellow
Green
Blue
Purple
Standard color wheel stuff.
@@CarbonRollerCaco the primaries of an additive colour system (i.e. light) are red, green, and blue. and the primaries of a subtractive colour system (i.e. paint) are CYAN, MAGENTA, and yellow, not red, blue, and yellow.
Keith Again, aesthetic perspective, not physical one. Ever think that red, yellow and blue all actually LOOKED LIKE their own entities while orange, green and purple LOOKED LIKE blends? That's what I mean. As Lois Lane once commented to Superman, "Red, yellow, blue… primary, but it works in a superheroish kind of way." (I may have screwed up the quote a bit since I couldn't find it, but the point about the idea being universal stands.)
It also lets you understand why with RGB Component cables that do not have a dedicated sync line put the sync line on green. And why green screens are used we are just more receptive to green light then the other primaries. So it will only display when green is put in and as for the mix ups with the reds thankfully modern day component cables will band the audio and video cables to keep them separate. But they really should have labeled those things I was a more composite kid back then and jumped straight to HDMI when I upgraded my video signals but I do use component for things now if my TV doesn't have ample HDMI slots.
.
And if you were around during the PS2 and Xbox era you needed component to access some of the game's higher graphical modes some games supported 720p on Xbox and on both had a handful at 1080i. So if your a gamer remember that its not just about the kind of cables you use for older games of that era, the applicable resolution is on a game to game basis. Even then though upgrading from composite to component can bring a more clear image even if the game runs in only 480p.
I wish you were already around when I started to learn about video signals. It took me ages to understand most of it, YPbPr is especially hard to grasp at first.
I suddenly understand everything.
we persist because we chose to!
15:25 is exactly why you sometimes see reds turn a bit orange-ish in online video. It's all rec 601 vs 709 mixups.
Oh boy, I can't wait to see what standard was used for multiplexing the Y', Pb, and Pr channels!
Your videos are tremendous and I am really glad your picking up the subs and recognition you deserve
Thank you!
0:05 To clarify, the primary subtractive colours are magenta, cyan, and yellow. Magenta and cyan is blue, magenta and yellow is red, and cyan and yellow is green. The additive and subtractive primary colours are opposite each other and are each other’s secondary colours, so the same colours can’t be both’s primaries. This has been known for hundreds of years, but is taught incorrectly all the time, and is not considered important enough to correct. Red, blue, and yellow will not cover most of the spectrum, and if they do it’s because they were mislabeled magenta, cyan, and yellow.
This channel and content is by far the best on the internet in explaining analog and digital signal for CRT/Tube TVs. I never understood how these digital RGB signals work until now. I hope theres a video which explains about how the composite signal for analog RGB are represented using your explanation with the oscilloscope Thanks.
Love your video, you are able to explain almost every weird technical aspect good that made me more in tune with what you are talking about ...
Interestingly enough our eyes detect RGB via the cones but our brains actually represent and process vision very similar to component. We perceive the brightness, the red-green scale, and the blue-yellow scale.
That is why we can imagine a redish-blue (magenta which is entirely abstract btw) and a blueish-green (cyan) but not a redish-green or a blueish-yellow
amazing explanation and great animations!
Your videos may be sparse between release but always very informative and of quality.
I'm not overly technical but I still enjoy these videos and your explanation is great, first one since I subbed so it's a good Friday lol. Love the channel already, man!
This entire series on how analog video works has been mighty interesting and fairly easy to understand. Thank you very much for making them.
Awww, over too soon! I was looking forward to you talking about how color in composite video is done by phase-shifting! :)
You put out amazingly informative videos, your channel is gonna blow up 👍
These videos are great! I will happily watch any video tech uploads you make in the future!
I just can’t believe how long I have been oblivious to the existence of such an interesting UA-cam channel with such a great and in depth content
A great serious of videos on video signals. I knew most of it, but you made it so clear and I learnt a few more things.
Perfect explanation. I sometimes struggle trying to explain these things to folks around me, but you broke it down in such an incredibly easy to digest way. Awesome job!
Fantastic video!! It was very entertaining and informative!! Cant wait for the next installation 😁
Love this video. Electronic color is SUCH a complex topic, but you explain it well.
Whenever I see the word "component" I think of how expensive the Gamecube component cables are.
The Wii ones were more affordable and I think they're backwards compatible
@@joey0guy The Wii and GameCube used different video connectors... The GameCube had the same port used by the SNES and N64 that can output Composite or S-video (and audio), plus a second "digital" output that was originally used with a special cable that has circuitry in it to convert this digital signal to component video (no audio). Later production GameCube consoles lack the digital out port as few people purchased the component video cable. The Wii essentially combines the two ports and eliminates the need for the special in-cable circuitry for component output. There are aftermarket solutions for the GameCube, but these are still over a hundred dollars.
The good thing is reverse engineering allow us to have that cable for less money
Third party cables have finally come out that are around $90. Still expensive, but not as expensive.
I want to say I bought those cables circa 2005. While it makes sense that they increased so much in price years later, the fact they ballooned that much is crazy.
Happy to see the modern alternatives. Options are always good, in my opinion.
Very informative Video! Concise and excellently illustrated! Thank you for putting in so much effort
Excellently produced video. Clear, precise and easy to understand.
Very clear and concise explanation! I hope the next episode in the series will cover S-Video, as I'm really interested in seeing how the color subcomponents are combined into a unified chroma signal. I know it's supposed to work like a vector sum of the components, but I'm not sure how that affects the resultant signal waveform.
S-Video was originally part of this video - at least from a scripting/audio standpoint. The video was way too long and needed even more details specific to s-video added to do it justice. Rather than do that, I decided to focus on component video. My current plan is to have s-video take the next video of this series when I pick it back up.
It is rather difficult to walk the line between concepts and math when making a video as math explains things in a very direct and objective way but it is also a quick way to lose people.
I promise to give s-video my best, Boris.
@@DisplacedGamers where's the video
This is one of the most interesting series of videos I've seen on this subject, super well explained and super easy to watch :)
Best explanation on youtube! Thank you!!!
This is an amazing video. As someone who has written their own music and has done their own sound design with FM synthesis, the combination of RGB pretty much act the same as Sine/Square/Saw/Triangle. Even more fascinating is the comparison to creating more varied colours and sounds through tighter frequencies. For example, there's a very popular sound string in dance music called the Hypersaw, or Supersaw. If you overlay loads of Saw Waves and then detune them slightly from one another, you create what is known as a "phat" sound, the type you hear in tunes like Rank 1 - Airwave. Colours on TV and consoles operate in a similar fashion as they are basically detuned colour waves, that are then frequency modulated (FM) with other colour waves. The depth of the detuning depends if the technology can do that, otherwise known as the bitrate. Like sound, there's a limit to what the human body can pick up, so 32bit colour is the maximum limit for the human eye, much like 20hz to 22khz is the maximum range for human hearing.
Thanks. Very high signal to noise ratio in this explanation. Also easy to follow. I never had to back up and rewatch any portion.
This is an amazing video that’s criminally underviewed.
Damn this such a clean and awesome work!! Thank you so much for this video
Loved the signal graphs, perfect way to understand Chroma, I learned a few things.
You explain stuff real good
Does the difference in color standards between SD and HD explain why SD content looks dark on an HD display?
Yes, but this can happen within S.D. color standards, as well. I have hooked up a Sega Genesis to a Sony PVM 8042Q, via RGBs, component, and composite. I was surprised to see that RGBs, along with being clearer, has a definitive color vibrancy, compared to component connections. I had forgotten that Phonedork had briefly mentioned this happening, in his setup, hence why he preferred RGBs. Anyways, I immediately remembered that RGBs has a FULL 8-bit color palette. There are 255 dedicated bits for the three primary seeable hues, for each pixel. Component video has video bandwidth for what is called reduced RGB. There is ONLY color information for bits 16-235.
@@badreality2 The 0-255 vs 16-235 is only used in digital forms, in analogue both use the same ranges. It's also values, not bits. When calibrated correctly the colour should be identical.
An HD display should already be picking the proper standard for SD inputs but if it doesn't, yes you can end up with greens darker than they should be and reds/blues too bright, and you'll notice the greens more.
@@linuxbot3000 When you say "calibrated correctly", do you mean adjusting the chroma, brightness, hue, and contrast, for the 16-235 component video, to look exactly like full 8-bit 0-255 RGBs?
@@badreality2 Yes. In analogue form there is no 16-235 / 0-255, it's just 0-0.7 volts for both.
Great video, can't wait for the others in the series.
thanks mate, your explanation with visual make more easy to understand
Excellent video, amazing production. Great job
Well said and thoroughly demonstrated. Thank you
Best description video i saw, ever! And beeing a crt nerd its by far not the first time watching one😂
Not going to lie, I love this info!!!! Great work
When you're talkin about Pb and PR, under the black color on the chart there's a little bit of luma above the baseline to the right of it. Why is this shouldn't black be at 0 luma, is this the function of the fact that black colors on a CRT television are still made by a light gun instead of the off state for a self-emitting diode like on OLED? If this question is answered later in the video I apologize.
This is really excellent. Great work!
Aw man..... Was really looking forward to hearing you talk more about what YUV is, as I've seen it on many various converter boxes & was curious to know exactly how it relates to Component & if I'd still be safe buying a converter box that uses the term YUV and hooking up Component Video to it. Fantastic video tho nonetheless!
you mentioned your luma video in the beginning, but there is no link for it in the description. just wanted to mention that because i feel others might look there for it also.
Sorry about that. Updated.
@@DisplacedGamers No apologies needed. I learned a great deal from these videos, and I hope others do the same. Thats the only reason I mentioned it. Thank you for your work here, and on the excellent quality of your videos in general. Really is something unique, and your delivery is easy to follow and soak up.
I like your style, simplified, but not dumbed down
I approve of this video. It speaks to me
0:47 "In a previous video we examine luma... if you haven't watched the video on luma yet I recommend you do so prior to continuing with this one"
Where is the link to the previous video? Could you please put it in the video description? Edit: found it! ua-cam.com/video/Ymt47wXUDEU/v-deo.html
Sorry about this. I believe I had the card created that was supposed to pop up in that exact moment in the video as a link on UA-cam, but I guess those aren't very reliable.
Thanks for editing your post to link it. I've added it to the video's description.
amazing video. i'm still confused about one thing about rgb vs ypbpr, and that's the chroma subsampling part. is ypbpr alwyas chroma subsampled and how does this affect "quality" (perceived or not) vs RGB?
I have my PS2 connected via YPbPr component and in college I remember playing around with the cable placement trying to see what kind of crazy things I could do with the jacks. I was expecting "if I only plug in green, I'll only get the green part of the image" kind of thing, but it unfortunately didn't work that way. Good to know now, and I might try some crazy combinations another time now that I understand it a little better.
If you only had green plugged in you should have only had a black & white image
@@BushidoBrownSama yeah, that's what happened.
I was looking to make sense of this yeaaars ago. Thanks for the explanation.
I remember hearing that the two colour signals were chosen and prioritized so that you can have luma and just one colour signal and that would be enough for some people. Could display flesh tones and other stuff. Surprised you didn't mention that.
Nice, I relearn a few things I have forgotten about.
Who invented YPbPr & what was the intended use case? What were the first consumer devices that used YPbPr?
I know Japan's Hi-Vision system alternated between YPbPr and RGBHV for interconnects between hi-def video sources & hi-def displays.
But then there are standard def TVs that also have YPbPr but when did those become a thing?
channels i found during quarantine.
Thanks. Some questions:
[1] What was the "1. advance technology" fork option?
[2] By the time we got Y'PbPr output, was being able to plug luma into b&W TVs seen as necessary? Why not switch to real RGB then?
[3] Why is the luma rca plug and input dressed up in green?
Option 1 would have been to make a new incompatible TV signal. Transmitting R, G, and B just as they are, separately over the air, would have been simpler, made TVs less complicated, and resulted in better picture quality. However, it wouldn't have been backwards compatible with old TVs. NTSC and PAL instead invented these more complicated schemes to allow old black and white TVs to still show the picture.
amazing explanation!
I used to switch PB and PR all the time to make funny colors.
More like this please.
Wonderful presentation 👏👌
Totally amazing!
The primary subtractive colors are cyan, magenta and yellow, not blue, red and yellow. Close enough though, I suppose.
I have an old Mitsubishi crt that can switch between YPbPr or Y R-Y B-Y by toggleing a switch. I am confused as to the practical application of this switch. Specifically, what use does it serve on my TV? And, which should I use for watching movies and playing video games? I have it set to YPbPr because I think the colors look better. Here is a video I did on the TV. You can see the switch I'm taking about early in the video
ua-cam.com/video/kBSqAauGEbA/v-deo.html
Eddit. I checked and the switch actually says YCrCb and not YPbPr but I think this is an error by Mitsubishi because the signal is analog and not digital.
I'm building a retro 8bit computer (50MHz) will have siftware based VGA and composite video, should I add hdmi encoder chip ($4) or ruins the retro feel?
Could you show the 'primary' colors i.e. red, orange, yellow, green, blue, purple, brown, black, through color bars and the oscilloscope? When I say 'primary' I mean the same colors we typically see in the 16 color crayon box we all grew up with. I think that would also help visualize what makes which color when talking video.
Great video. Any reason why the Luma cable is green? Seems like conceptually it would have made sense to be white.
Maybe because it carries most of the green component, and also because the left audio channel is already white.
Do you think you could figure out why it's so difficult to get interlaced from HDMI? I can't get my pi to go from 480p to 480i to my PVM CRT >
Just subbed!!!
0:00 uh... cyan, magenta, and yellow. You can't make a full subtractive spectrum with red/blue. :|
Pretty much this. You'll get people that hang onto their kindergarten knowledge of it being Red Yellow Blue but it is Cyan Magenta Yellow for subtractive. (Cyan looks a bit blue, Magenta looks about red, hence the kindergarten knowledge being simplified).
Xilefian hit on it a bit. The segment was meant as more of a segue than a declaration - it was meant to shift people out of RBY primaries and into additive RGB.
@@DisplacedGamers just trying to prevent people from drawing a lot of mud ;)
can i convert the two chroma and luma inputs into a single composite input?
I still don’t understand how white can be coded back to green whether via composite or component, and while i do know that RGB can be mixed together to get B&W for B&W tv sets ,trough i can imagine that if you would only convert green to B&W for B&W tv’s then lots of details will get lost,,
So how can a color tv retrieve the green signal from the mixed luma signal?
Amazing... thanks..
When it's time to talk about composite video, please mention or illustrate how the YIQ colour space is or should be converted to RGB YPbPr/YCbCr. Because its axis are rotated in relation to the YPbPr axis, it seems to me that colour conversion from YIQ is lossy. Please address that and thanks for this great video.
The space where YIQ and YPbPr space don't overlap is outside RGB space anyway, so in practice it is lossless.
@@linuxbot3000 Wait I thought Composite video used the YUV color model, where does YIQ come in handy then?
@@Ballowax the goal of the slightly rotated YIQ in NTSC vs YUV was so Y would be a little closer to the ideal orangey-bluey axis human vision cares about to spend a little more bandwidth on it with the asymmetric modulation (and also do that TVs with only two primary colours could be made but was soon realises that it's not enough cheaper to care), but then all the manufacturers stopped caring and just treat it as slightly rotated symmetric bandwidth YUV anyway
@@linuxbot3000 So basically NTSC Composite video uses YIQ while PAL Composite video uses YUV? I know that the big difference between YIQ color and Y-Pb-Pr is that YIQ was built around the way the human eye perceives color.
With YIQ, you get a smaller color spectrum than Y-Pb-Pr as YIQ was made to help TV stations reduce the amount bandwidth you would need to broadcast an NTSC color video signal. Y-Pb-Pr will also allow you to compress the chroma information, but it will give you a much richer color palate than YIQ. Y-Pb-Pr gives you color on two separate signals while YIQ mashes in all the color information with no separation. After all RF, Composite, and S-video carry all of the chroma information on one signal.
@Ballowax 2002 NTSC old specs used YIQ, practical NTSC gear almost always use YUV = YPbPr. The spectrum you get is identical, both are limited by the range of valid RGB values they decide to.
YIQ and YUV are both using the same two signals on one chroma wire QAM method, it's just slightly different implentation
what about Y BY RY? my mitsubishi has component, it says YCbCr (although I'm told it's mislabeled), but it does have a switch to change it to Y BY RY.
I've heard many times that "NTSC colour signal is compatible with NTSC B/W sets because they choose compatibility before technology" and "PAL colour signal is incompatible with PAL region B/W sets because they decided on more advanced technology at the cost of compatibility", but many a relative of mine had old PAL B/W TV sets (from before colour signal was introduced in my country) that worked just fine with regular colour broadcastings and I'0m even told of a foreign colour TV set a relative purchased abroad that worked just fine with the B/W signal used at the time in my country...
pal color was compatible with 625 line b/w tvs but was incompatible with 405 line b/w tvs
@@gamecubeplayer Going from what I can find about 405 lines, it seems like the system was never in use in my country, as it was UK-based, so that thing they say about "PAL throwing away compatibility with older sets" should be instead "broadcasters of the UK sphere throwing compatibility out of the window and adopting a new standard".
Stellar as alway.
I used to think Component Video was RGB. Now I understand.
Sorry but I think you misunderstand the primary subtractive color. subtractive color is not red, yellow and blue. It is Cyan, Magenta and yellow. Cyan is not Blue and Magenta is not Red. That is why it is called CMY for subtractive not RBY. And RGB for additive. But still Great Video. 1 thumbs up.
Rec. 601 is also used for Enhanced Definition video (480p, 576p).
AND what about s-video?
Where did you learn this?
Amazing video. Please tell us how progressive and HD modes of YpBpR came to be, but RGB SCART never got them, at least not standardized to a degree where consumer devices would accept it.
An interesting topic. Let me try to push into the past a bit more first and then maybe I'll see what I can do on analog HD topics in the future.
@@DisplacedGamers Thank you! Now thanks to your oscilloscope demonstrations I know why while using cheap component cables I get more ghosting on contrasting edges as I increase resolution and why it always smears to the right. Bandwidth increases, peaks and dips are getting closer together and whites produce ghosting on blacks.
Meanwhile I'm like "wait, so not every combination of possible Y, Pb, and Pr valid is 'valid'? that seems like saying not every combination of R, G, and B is valid..."
Also, the way I always saw "YUV" visualized was as a cube, that the luma axis selects a "layer" of the cube, and that U and V (the standard axes for 2D textures) determine the coordinates on that layer, essentially acting as a 3D look-up table for what the final color output to screen will be. Maybe that's where I got the idea that all combinations of three values are valid to render...
Only thing I'd argue is the definition of Blue Yellow Red as the subtractive colors. As far as I know, it's Cyan Magenta and Yellow?
As in the video it is correect. Subtractive means the more color you add, the darker the image gets. As for television or other screens, the more color, the brighter the image.
This is cool af
CMYK!
What happens if you plug in Pb and Pr but not Y'?
Are you about to do composite video chroma
Thanks man, you have a great channel.
In Component video, Pb and Pr correspond to warm and cold hues. At least in positive range.
Color temperature alone is another fascinating topic!
I've never seen any device or TV that uses those RGB cables. I've seen RF, composite, S-Video, Component, and HDMI. In fact, I own a TV that has all of them. Was RGB not popular? Maybe it never caught on in the US?
YPbPr is equivalent to analog RGB in terms of quality, but YPbPr saves on bandwidth due to chroma subsampling. As such, there wasn't much incentive for analog RGB on consumer television sets in the United States. Analog RGB came along with personal computers since that's the simplest format for generated images. The DE-15 connector used for VGA displays uses the RGBHV standard, i.e. sync used separate pins for horizontal and vertical signals. Later on, the DVI connector was briefly utilized before being superseded by HDMI. DVI supported both analog and digital RGBHV signals, though some connectors were limited to analog only (DVI-A) or digital only (DVI-D).
Beyond consumer electronics, you could pick up a medical, broadcasting, or otherwise professional monitor that had separate BNC type connectors for RGBHV. Others have YPbPr and a composite video input that double as RGB with external sync (RGBS). The SCART connector that's used in Europe is actually just a universal connector that combines composite, S-Video, YPbPr (component), and RGB. It utilizes Sync on Luma for YPbPr and S-Video, and RGBS where the sync is the same pin as the composite video. Another standard called Sync on Green (RGsB) was used with the PlayStation 2 in 480p mode and with Silicon Graphics computers. This means that if you want to use RGB over SCART on the Sony PS2, you'll need a device like the OSSC that can translate RGsB to RGBS.
So why the niche fascination for RGB instead of component on retro consoles? Because consoles generate images which makes RGB mods simple, but they only had cabling for S-Video at best. Super Nintendo doesn't actually require any modification to get RGB, you only need an AV multi-out to SCART adapter. On the N64, you can directly pull the RGB generated image by soldering into the Reality Coprocessor. For the NES, parts of the PPU are bypassed so that you can use enhanced color palettes. Perhaps if early video game consoles were a bigger driving factor in the media consumption market then we'd have RGB inputs on early consumer sets. It was only until 7th gen consoles like the Xbox 360 and PS3 that YPbPr was used which would quickly be superseded by HDMI.
@@Anthony-cn8ll Nice
The example of RGB used in this video is RGBHV over 5 BNC cables & it is the same signal as VGA it just has a different connector anyways RGBHV more popular in the computer world than in consumer electronics world.
in Europe RGBS over SCART connections was very popular in the consumer world primarily because France used SECAM but most of Europe used PAL, RGBS bypases those color systems & conflicts altogether while all countries that border the USA use NTSC.
RGBS & other RGB types never caught on in the US consumer electronics world because there wasn't as much need.
#justacommentofappreciation
Every time when some noob call Ypbpr cables RGB, i giggle.
I'm watching this via NTSC composite cable.
Shit, it's 1am again
Whoosh
HDMI next!!!
Why is the standard called Rec 601, the red 0,701 is so close as a number that it's annoying. YUV makes me immediately think of all the times trying to capture signal on capture card and trying to find a proper setting for it to work.
Except, of course, the subtractive colour we learned when we were young was basically wrong. Red, blue and yellow aren't primaries no matter how you look at it.
It is correct. It is one form of subtractive color primaries. There is no universal single set of subtractive primaries.
I think several people that have commented on this have latched onto print primaries - ink based primaries that favor CMY - as the single set of possible primaries, however there are various sets of primaries. It depends on the medium.