[FFmpeg-user] h264_vaapi missing frames

Dennis Mungai dmngaie at gmail.com
Tue Mar 20 04:54:53 EET 2018


Hello there,

Have you tried using the restream option?

ffmpeg -re -i capture_device -vaapi_device /dev/dri/renderD128
-movflags +faststart
-vf 'format=nv12|vaapi,hwupload' -c:v h264_vaapi {$encoder_opts} outputfile.

Try and report back.

On 20 March 2018 at 05:30, Kai Hendry <kai.hendry at gmail.com> wrote:
> Hi there,
>
> With my brand new Intel 8th gen laptop (Intel Corporation UHD Graphics
> 620 (rev 07) with 8 core Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz on
> Archlinux, I thought I'd experiment with hardware accelerated capture
> as opposed to my normal 2-step approach of
> 1) recording to mkv
> https://github.com/kaihendry/recordmydesktop2.0/blob/master/x11capture
> 2) converting mkv to mp4
> https://github.com/kaihendry/recordmydesktop2.0/blob/master/htmlvideo
>
>
> However with -vaapi_device /dev/dri/renderD128 -movflags +faststart
> -vf 'format=nv12|vaapi,hwupload' -c:v h264_vaapi it seems to skip
> frames.
>
> https://s.natalian.org/2018-03-20/1521512464.mp4.log
> https://s.natalian.org/2018-03-20/1521512464.mp4
>
>
> Ffprobe seems to say it's 30fps:
>  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p,
> 2560x1440, 722 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
> (default)
>
> But during playback, it would appear not!
>
> Is there a good way to test or know I've dropped frames in my screen capture?
>
> How can I prevent frame dropping?
>
> Kind regards,
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