[FFmpeg-user] screen capture - small files

Thilo Borgmann thilo.borgmann at mail.de
Mon Nov 23 19:28:53 CET 2015


Am 23.11.15 um 14:09 schrieb Moritz Barsnick:
> 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.

choose "-pixel_format nv12". This is planar yuv420p and conversion
should be as fast as possible (if mpeg4 does not support nv12 directly).


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