[FFmpeg-user] New ffmpeg NVEnc options and errors

[hydra3333 at gmail.com]

> Extract of "C:\SOFTWARE\ffmpeg\0-homebuilt-x64\ffmpeg.exe" -hide_banner -v debug -h encoder=h264_nvenc
>   -rc                <int>        E..V...... Override the preset rate-control (from -1 to INT_MAX) (default -1)
>      constqp         0            E..V...... Constant QP mode
>      vbr             1            E..V...... Variable bitrate mode
>      cbr             2            E..V...... Constant bitrate mode
>      vbr_minqp       8388612      E..V...... Variable bitrate mode with MinQP (deprecated)
>      ll_2pass_quality 8388616      E..V...... Multi-pass optimized for image quality (deprecated)
>      ll_2pass_size   8388624      E..V...... Multi-pass optimized for constant frame size (deprecated)
>      vbr_2pass       8388640      E..V...... Multi-pass variable bitrate mode (deprecated)
>      cbr_ld_hq       8            E..V...... Constant bitrate low delay high quality mode
>      cbr_hq          16           E..V...... Constant bitrate high quality mode
>      vbr_hq          32           E..V...... Variable bitrate high quality mode


Ah.  Pages 17 onward from this nvidia pdf go some way to explaining it.

http://developer.download.nvidia.com/video/gputechconf/gtc/2020/presentations/s21337-nvidia-video-technologies-video-codec-and-optical-flow-sdk.pdf