[FFmpeg-user] screen capture - small files

Moritz Barsnick barsnick at gmx.net
Mon Nov 23 14:09:15 CET 2015

On Mon, Nov 23, 2015 at 08:27:02 +0100, Jesper Hedin wrote:
> ffmpeg  -f avfoundation -i "1:0" -c:v mpeg4 -c:a aac -strict -2 -r 3 -b:v 1024 out.mp4

Another recommendation (OT):
You are using "-r" as an output option. So you are resampling whatever
capture framerate your device gives you to 3 fps. You are probably
*not* capturing at 3 fps. If you had shown us your complete console
output, I might have been able to tell. ;-)

I recommend using the input option "-framerate 3" instead.

> [avfoundation @ 0x7fc535000000] Overriding selected pixel format to use uyvy422 instead.
> Incompatible pixel format 'uyvy422' for codec 'mpeg4', auto-selecting format ’yuv420p'
[avfoundation @ 0x7f9c24800000] Overriding selected pixel format to use uyvy422 instead.

None of the avfoundation device's pixel formats maps well to your mpeg4
output. If yuv420p output is okay for you, ffmpeg is probably already (by
chance) choosing proper pixel format settings and conversions for you,
but you can choose to select what you need manually, by specifying
input "-pixel_format" and output "-pix_fmt" options.


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