[FFmpeg-user] Trouble selecting a pixel format/colorspace while trying to encode a video using ffmpeg and HW accelerated vaapi or qsv interfaces

[caetano at vision.ime.usp.br]

  The second link in my last message is wrong, the correct one with the
summary of the media features for Intel GPUs is:

https://github.com/intel/media-driver/blob/master/docs/media_features.md

On Sun, 11 Dec 2022 at 18:44, <caetano at vision.ime.usp.br> wrote:

>   My question is not related to post-processing or color-space
> transformation. It is about how to hardware encode using a pixel format
> that provides high color accuracy for screen capture, differently from what
> NV12 is capable of offering.
>
>   Regarding hardware encoding support, accordingly to this:
>
> https://github.com/intel/media-driver/blob/master/README.md
>
>   Hardware support has been added since Ice Lake (2019, 10th generation) to
> HEVC and VP9 codecs for 4:4:4 chroma for both 8 and 10 bits modes and also
> for both encoding and decoding.
>
>   This other page gives more details:
>
> https://github.com/intel/media-driver/blob/master/README.md
>
>   Accordingly to the above link , the following 4:4:4 formats are supported
> for hardware decoding when using HEVC or VP9: AYUV (8 bits) and Y410 (10
> bits) and the following  4:4:4 formats are supported for hardware encoding
> when using HEVC or VP9: AYUV and RGB (8 bits) and Y410 (10 bits).
>
>   I've found out that gstreamer in my system (ubuntu version 1.20.1) is
> able to perform 4:4:4 10 bits encoding when using the Y410 format and the
> following command (ffprobe for the generated file reports pixel format
> as yuv444p10le):
>
> ====
> gst-launch-1.0 ximagesrc display-name=:0.0 show-pointer=false
> use-damage=false num-buffers=2400 ! video/x-raw,framerate=20/1 !
> videoconvert ! video/x-raw,format=RGBx ! vaapipostproc !
> video/x-raw,format=Y410 ! vaapih265enc rate-control=cqp quality-level=1
> quality-factor=18 ! video/x-h265 ! h265parse ! matroskamux ! filesink
> location=desktop.mkv
> ====
>
> and hardware decoding of the above generated file can be achieved with the
> following command:
>
> ====
> gst-play-1.0 desktop.mkv
> ====
>
> Unfortunately, gstreamer version I have has no support for the AYUV pixel
> format with hardware acceleration, therefore I could not test 8 bits
> hardware encoding and decoding, but at least for 10 bits it is working
> properly and colors looks just great.
>
> ===========================
>
> I believe it would be great to add support in ffmpeg for hardware encoding
> and decoding for at least the following 4:4:4 pixel formats: AYUV, RGB
> and Y410 as this is available in Intel hardware since 2019.
>
>
>
> On Sat, 10 Dec 2022 at 17:00, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>
> > I wanted to write "no hardware encoders support full chroma" and
> > "no hardware encoders support RGB" - Wenbin's answer seems
> > to indicate that I was wrong but in any case the qsv code in FFmpeg
> > currently neither allows full-chroma encoding nor RGB encoding.
> >
> > I don't know if mxf (the library used for qsv encoding) support
> > full-chroma and RGB.
> >
> > No idea how your question could be related to post-processing
> > or colour-space transformation.