[FFmpeg-user] ffmpeg -f avfoundation HELL - please help!

Demián Andrés Rodriguez demian85 at gmail.com
Tue Jan 3 19:34:10 EET 2017

Thanks for your reply.

I hardly believe my cpu cannot encode vp9 properly, since cpu does not go
beyond 100% while using h264 uses more than 300% cpu.

Also, h264 encoding produces a very good video output but audio stutters
and is very unclear. There are gaps in the middle...

Also, setting -video_size 480x240 seems to have no effect at all. How can I
change output video size?

On Tue, Jan 3, 2017 at 2:22 PM Moritz Barsnick <barsnick at gmx.net> wrote:

> On Tue, Jan 03, 2017 at 16:55:47 +0000, Demián Andrés Rodriguez wrote:
> > > frame=   16 fps=1.7 q=0.0 Lsize=     998kB time=00:00:09.52
> bitrate=858.9kbits/s speed=1.01x
> > > video:993kB audio:0kB subtitle:0kB other streams:0kB global headers:4kB
> [...]
> > > frame=   32 fps=3.7 q=0.0 size=       1kB time=00:00:01.65
> bitrate=2.6kbits/s speed=0.193x
> > > frame=   33 fps=1.5 q=0.0 Lsize=    1423kB time=00:00:09.08
> bitrate=1283.6kbits/s speed=0.422x
> I think your processor is way too slow to encode this resolution to VP9
> in realtime. That probably leads to skipping frames (in the long run),
> and as a side effect possibly breaking audio. VP9 encoding is known to
> be quite slow. You need to choose a lower resolution, faster encoding
> parameters, or even a different codec.
> Have you tested with "-c:v libx264 -preset ultrafast", to see whether
> the resulting video+audio is fine? (It needs to encode at speed >= 1.0
> or fps >= 25 then of course, but I'm quite optimistic that it can.)
> Moritz
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