What is the misconception with YUV in terms of quality?

[headlesshobbs]

From time to time I've seen where someone posts images of a game that is displaying via YUV component and in comparison their pics show they don't look any different in picture quality when compared with native RGB sources. YUV from what I understand is an uncompressed format of analog color space meant to save on bandwidth based on a chroma/luma formula which itself was based off the ntsc system. Now with comparisons I've seen those that match RGB had been on displays that were re-calibrated to show their levels were clearly even aside from the difference in contrast.

This makes me wonder if having a console with YUV as it's only option wouldn't be any different from one that is RGB modded?

This also brings up a number of other things like why tv's need to be modded if from component, or if the color space practically the same why isn't there a technical look on how the levels can be adjusted so much as we do with scart? Uncompressed YUV offers a better quality advantage in detail with higher resolution modes, so why not add a viewpoint on where this can be taken advantage of?


I'm really failing to see this idea where RGB is superior to YUV and I wish someone could help me to address this. It's obvious when 4:2:2, 4:2:0 is on the table, but 4:4:4 is where I see this is a huge deal.

Btw, anybody wanna tag the guys from RetroGamingCables to get in here since they favor component cables so much? This topic is right in their alley and I could use some perspective from them.

[PixelDharma]

I've wondered about this myself. For example, what's the wiser choice: converting component to RGB, converting RGB to component, or is there literally no quality difference going either way?

[headlesshobbs]

Good question.

My concerns have always been about keeping 4:4:4 throughout the conversion process, being that the system sends and the tv receives and displays the same signal. I wasn't given a spec sheet on tv's that had just arrived when component was a new thing, but analog should have meant they could run the full range without any problems should they receive it. I'm trying to read about the other consoles now, because I've noticed Wii falls under applying 4:2:2 Chroma subsampling before being sent as YPbPr and the worry is if it changes the color pallet on all those low res ports it got via the WiiShop. PS2 I don't know about, but XBOX had something to do with having no Chroma sampling, so I'm wondering if that's what made the video darker?

[matt]

It's not the video signal itself that's the problem - what happens is that many TVs add edge enhancement and/or softening effects to the signal that degrade the image quality in games. An RGB mod usually will bypass this and result in a cleaner picture.

All else being equal, YUV and RGB will have no perceptible difference in picture quality.

[nissling]

YUV is not a signal, it's a color model. Much like XYZ, xyY, LUV etc.

One benefit with RGB over YPbPr is that the nominal values mean that chroma and tint will always be correct. With YPbPr, they can theoretically speaking be off but you must have one really crappy display if this cannot be corrected (in most cases you can just leave chroma and tint at default). In the digital domain this is pretty much never an issue. I've also seen quite a number of CRTs that give halos when using YPbPr while remaining clean when using RGB, at least in resolutions up to 480p.

Apart from this, there's nothing wrong with opting for YPbPr.

[strayan]

It's not the video signal itself that's the problem - what happens is that many TVs add edge enhancement and/or softening effects to the signal that degrade the image quality in games. An RGB mod usually will bypass this and result in a cleaner picture.

All else being equal, YUV and RGB will have no perceptible difference in picture quality.

This is true and extremely irritating.

Converting component to rgbhv before passing it to your flatpanel is necessary in almost all cases.

[headlesshobbs]

CRT sets were perfect when component was first introduced to them and it made me so happy when I discovered the Wega had 480p support. Had things not gone down the shitter for me, I would have picked up a CYP transcoder and I would have tried finding a way to convert my Dreamcast's VGA.

[gray117]

You often hook up RGsB via component? So, I wouldn't necessarily assume all component mods/devices are actually YUV - I would have actually assumed they weren't, unless this became a fairly common option for US cable/broadcast boxes and thus tv's at one stage?
...

In terms of typical user experiences, some form of analogue component was probably the halfway house for many between analogue composite and digital connects (such as hdmi), which again, won't have been necessarily been a fair comparison... especially depending on how well/poorly their tvs coped with it.

I would assume these days the misconception is that YUV in analogue YPbPr and digital YCbCr uses is often employed within various means of reduction/compression - which inherently contributes to the idea that it's not the best way to go in terms of 'quality'.

...

For convenience in terms of analogue sd content, component crts are still relatively rare in States afaik, and very rare in the Euro zone; which makes them a nice choice if you have the option, but hardly an easy recommend for everyone.

But yeah when people talk in terms of the 'best' option, it's very easy to conflate that with 'quality', it's unfortunate, but not suprising imho, that people will tend to be surprised to see perfectly good images from component sources - just because it won't commonly be pushed as the 'best' way to go for everyone.