Chroma subsamlping 4.4.4

[Orion3000]

First I wanted to thank you a lot for the latest update amazing work as always. I had a small issue with the latest update. When I use the NVENC with AV1 and select profile level high444 and select sampling 444 and select 10 bit everything works fine except media info report the Chroma as 4.2.0 instead of 4.4.4. I tried to encode using high444 and sampling 420 and both gave me the same result as Chroma 4.2.0 and not 4.4.4

 This issue doesn't happen with h265 so my question is it the AV1 fault or is it something wrong with the latest update? I have a RTX 4090 GPU if that helps. 

Again thank you so much for all you do.

[Selur]

NVEnC writes it supports:

h264:  auto, baseline, main, high, high444
hevc:  auto, main, main10, main444
av1 :  auto, main, high

see: https://github.com/rigaya/NVEnc/blob/mas...ile-string
And high should support 4:4:4 color sampling (see: https://aomedia.org/av1/specification/annex-a/)

But it does not, and I simply forgot to disable the options.

You can test it yourself, if you for example use:

ffmpeg -y -loglevel fatal -i "G:\TestClips&Co\files\test.avi" -map 0:0 -an -sn -vf zscale=rangein=tv:ran
ge=tv -pix_fmt yuv444p10le -strict -1 -vsync 0 -f yuv4mpegpipe - | NVEncC --y4m -i - --fps 25.000 --codec av1 --profile high --output-depth 10 --colorrange limited --colormatrix bt470bg --cuda-schedule sync --output "G:\Temp\test_2022-11-30@19_30_41_4610_01.av1"

Where you feed NVEncC explicitly with 10bit with 444 content, it will output:

Input Info     y4m(yuv444(10bit))->p010 [AVX2], 640x352, 25/1 fps
Vpp Filters    copyHtoD
Output Info    AV1 main 10bit @ Level auto

which converts 4:4:4@10bit to 4:2:0@10bit (p010)

According to https://docs.nvidia.com/video-technologi...tion-note/
Ada GPUs support AV1 main profile and thus are capable to encode YUV 4:2:0 8-bit and 10-bit content up to 8192 × 8192 resolution, but not 4:4:4. (that would be high profile)
So your GPU does not support 4:4:4 AV1 encoding.

=> I'll adjust Hybrid to disable Profile, Level, Sampling for the next release.

Cu Selur

[Orion3000]

I can't thank you enough for the explanation. As always thank you for your amazing work. I gotta blame Nvidia for that then   

[Selur]

Also send you a link to a dev version which should disable the options when av1 is used.

Cu Selur

[Orion3000]

Got it thank you