Can I keep pixel perfect quality on Y′UV, YUV, YCbCr, YPbPr, etc ?

[synnchan]

I recorded a video with RGB, YUY2 and YV12... and I noticed pixel perfect lossless quality is only kept on RGB. Here is a side by side comparison:



Is it possible to make it so the pixels will look lossless perfect on Y′UV, YUV, YCbCr, YPbPr, etc as well?

[poisondeathray]

This is the effect of chroma subsampling
https://en.wikipedia.org/wiki/Chroma_subsampling

It's possible by encoding without subsampling (e.g. YUV 4:4:4) , but not all devices or decoders support this . So it depends what the scenario is or background information, or how this is going to be used

[synnchan]

Can HTML5, Flash or Silverlight ACTUALLY support and play RGB?

[poisondeathray]

Can HTML5, Flash or Silverlight ACTUALLY support and play RGB?

officially, no

but there were a few snapshots that could, even 10bit support

But for general public use, if you want it to actually work on the majority of targets, you need to use 4:2:0 (yv12)

[raffriff42]

Capture in RGB.
Double the size (or 3x, or 4x, or 5x like you did here).
Finally, convert to YV12.

Not perfect, but much better, and YV12 plays everywhere.

[poisondeathray]

I posted some 4:4:4 vp9 / webm tests over a year ago in this linked thread below. You can download and test if your browser version supports it or plays it back properly

https://forum.videohelp.com/threads/371183-VP9-webm-1-4-officially-supports-YUV444-now

Full color has been supported on the encoding side for quite a while (much longer for h264), but not widespread for browsers yet. It's still much safer to use 4:2:0

[pandy]

Use any codec capable to support RGB OR\AND YCbCr 4:4:4. If from some reason using such codec is not possible then follow raffriff42 advise and enlarge your source by 2 or 4 - point resampling will be mathematically perfect way (but least pleasant).

[jagabo]

Capture in RGB.
Double the size (or 3x, or 4x, or 5x like you did here).
Finally, convert to YV12.

Not perfect, but much better, and YV12 plays everywhere.

Don't forget to use the point resizer for the chroma when converting to YV12:

PointResize(width*2, height*2) # or *4
ConvertToYV12(chromaresample="point")

[synnchan]

Lemme see if I got it right... you mean if the video is 256x224, then doubling it into 512x448 or making it 1024x896 will fix the problem? I tried both with point resize but it still doesn't look perfect.

[jagabo]

Lemme see if I got it right... you mean if the video is 256x224, then doubling it into 512x448 or making it 1024x896 will fix the problem?

No, it only reduces the problem.

I tried both with point resize but it still doesn't look perfect.

Even though you've controlled the upscaling you can't control what the player does during playback. Players will usually use a smooth algorithm to upscale the chroma (to the same size as the luma) so you will still get a little blurring of the colors. But much less than if you had encoded at the original resolution.

Your 256x224 RGB video has 256x224 R, G, and B planes. When converted to YUV with 4:2:0 chroma subsampling you get a 256x224 Y plane (greyscale image) and 128x112 U and V planes (color information), hence the blurring of the colors. By doubling the frame size first you get a 512x448 Y plane and 256x224 U and V planes. During playback the player upscales the 256x224 U and V planes to match the 512x448 Y plane.

As noted earlier, if you want sharper colors you need to YUV 4:4:4. OrRGB 4:4:4. But those are not commonly used in files meant for distribution/playback.

[synnchan]

okay, thanks. But I have another question: is there a way to do the ConvertToYV12(chromaresample="point") without avisynth? I have it installed, but I'd rather use virtualdub's filters alone if possible.

Is there a filter I could use to point resize the chroma?

[pandy]

okay, thanks. But I have another question: is there a way to do the ConvertToYV12(chromaresample="point") without avisynth? I have it installed, but I'd rather use virtualdub's filters alone if possible.

Is there a filter I could use to point resize the chroma?

If possible perform operation at RGB space then you don't need any additional filters (postpone conversion to YCbCr till last step) - AFAIR VirtualDub natively working in RGB space so you should have no problems.