[Libav-user] Nvenc_H264 very slow compared to Libx264

[Jodon Karlik]

On Thu, Jan 16, 2020 at 5:28 PM Philippe Noël <
philippe_noel at college.harvard.edu> wrote:

> Hi,
>
> I was using libx264 to encode a video file using libav from a C file and
> switched to nvenc_h264 and now the encode is very slow. It appears
> nvenc_h264 does not have a "ultrafast" setting.
>
> With nvenc_h264 I am using preset "llhq" and tune "zerolatency". Am I
> using the wrong settings?
>
> Cheers,
>
> Philippe
> _______________________________________________
> Libav-user mailing list
> Libav-user at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/libav-user
>
> To unsubscribe, visit link above, or email
> libav-user-request at ffmpeg.org with subject "unsubscribe".


In my experience, x264 is very fast and you may not be able to beat it at
low quality.  That said, there are a lot of possibilities for why it may be
slow.  Look at:
https://devblogs.nvidia.com/nvidia-ffmpeg-transcoding-guide/ which will
give you some tips for minimizing PCIe transfers to keep it fast.

Cheers.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://ffmpeg.org/pipermail/libav-user/attachments/20200116/8556f3b8/attachment.html>