1

I was trying to make some recordings of a game (with OBS), but it wasn't really good even with "lossless" options. Some part of the interface was just pixelated... After a while I realized that the chromatic subsampling should cause the problem, as the pixelated interface is red. (In OBS the default color format is NV12, using RGB instead - without subsampling - it was all good.)

Is there a workaround to keep the resolution of the interface intact, but still do some kind of chromatic subsampling? (Maybe with some other color encoding than YUV?)
It's Ok if I need to make the recordings without subsampling, and than convert/transcode the videos. I would do it anyway, as OBS can't record with hevc_qsv. Also I don't have an intent to publish these videos on the internet. (Probably I'd like to store the videos using H265 or AV1, to obtain the best compression.)

1

No. Almost all video on the planet is limited YUV420 (all Blu-rays, even HEVC ones with Dolby Vision, all Youtube, only some satellite FEEDs not for consumers use 4:2:2). Sorry. Of course, there is RGB and even mathematically lossless mode in all common encoders, H.264/AV1/VP9/HEVC... For lossless AV1 see https://trac.ffmpeg.org/ticket/7600

But, alas. It is not used at all.

Only Dolby Vision in profile 5 that is not HDR10 compatible (it uses IPTPQc2 color instead of YCbCr and FULL RANGE) can be good enough for you. It still uses 4:x:x chroma but because of new encoding it is much better looking!

2
  • Yeah, I suspected. Thanks for your answer. Anyway using OpenGL ("for Windows") as video output instead of Direct3D(9) also helps a bit. It must use some kind of interpolation, so at least it's just a bit blurred, rather than pixelated. – fanyul Mar 21 at 21:20
  • Huh, I randomly found some options (with x265 encoder, but others might have this as well): "CrQPOffset" and "CbQPOffset". With these it is possible to apply different QP ("quality") values for the "Cr" and "Cb" components (relative to the overall QP value). This seems to be about as effective as chromatic subsampling, but more flexible. Using these and YUV444 colors there is no observable resolution loss. :) (Also I think these might be used with NV12/YUV420 or YUV422 to obtain even more compression, but I don't know how this would effect the colors.) – fanyul Mar 26 at 18:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.