NOTE: Use the vainfo command, to figure out for which codecs GPU hardware video encoding acceleration can be used with:

vainfo

returns:

vainfo
libva info: VA-API version 1.16.0
libva info: User environment variable requested driver 'radeonsi'
libva info: Trying to open /opt/amdgpu/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_16
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.16 (libva 2.12.0)
vainfo: Driver version: Mesa Gallium driver 23.3.0-devel for Radeon RX 7900 XTX (navi31, LLVM 17.0.4, DRM 3.54, 6.5.0-15-generic)
vainfo: Supported profile and entrypoints
      VAProfileH264ConstrainedBaseline:	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointEncSlice
      VAProfileH264Main               :	VAEntrypointVLD
      VAProfileH264Main               :	VAEntrypointEncSlice
      VAProfileH264High               :	VAEntrypointVLD
      VAProfileH264High               :	VAEntrypointEncSlice
      VAProfileHEVCMain               :	VAEntrypointVLD
      VAProfileHEVCMain               :	VAEntrypointEncSlice
      VAProfileHEVCMain10             :	VAEntrypointVLD
      VAProfileHEVCMain10             :	VAEntrypointEncSlice
      VAProfileJPEGBaseline           :	VAEntrypointVLD
      VAProfileVP9Profile0            :	VAEntrypointVLD
      VAProfileVP9Profile2            :	VAEntrypointVLD
      VAProfileAV1Profile0            :	VAEntrypointVLD
      VAProfileAV1Profile0            :	VAEntrypointEncSlice
      VAProfileNone                   :	VAEntrypointVideoProc

• For all entries with a value of VAEntrypointEncSlice hardware encoding can be used.

NOTE:

• -vaapi_device /dev/dri/renderD128, which is a shortcut to -init_hw_device vaapi=vaapi0:/dev/dri/renderD128 -filter_hw_device vaapi0, initializes a new hardware device of type vaapi.

• -vcodec hevc_vaapi

• -vf 'format=nv12,hwupload' creates the filtergraph and uses it to filter the stream.
  • The encoders only accept input as VAAPI surfaces.
  • If the input is in normal memory, it will need to be uploaded before giving the frames to the encoder; in the ffmpeg utility, the hwupload filter can be used for this.
  • It will upload to a surface with the same layout as the software frame, so it may be necessary to add a format filter immediately before to get the input into the right format (hardware generally wants the nv12 layout).
  • The hwupload filter also requires a device to upload to, which needs to be defined before the filter graph is created, which is done with -vaapi_device.

• -map 0 -c:a copy -c:s copy: This causes to copy the audio streams and sub without modification to the new file.
• -map 0:a -c:a copy: This causes to copy the audio streams without modification to the new file.

• -qp 23: The video quality.
  • The lower the value, the better will be the video quality, but also the files will be larger.
  • The default value is 25 which is fairly good.
  • For high-definition videos a value between 21-23 works best and produces good results.