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Re: Session Recording

Siard (2018-12-27):
> $ ffmpeg -f x11grab -s cif

"-s cif" means "-s 352x288"; most screens are larger than that nowadays.

>			     -r 24 -i :0.0 /tmp/out.mpg

Outputting to a file named .mpg without options will result in video
encoded in MPEG-1; this is far from the better option. Furthermore, it
will use the default quality settings, which are quite low.

Better use a more modern codec. For example, with the very mature x264,
and Matroska container, this would be a good starting point:

	-c:v libx264 -preset fast -crf 20 out.mkv

The crf value controls the quality of the output, lower is better,
higher is smaller; the preset option controls the effort to reduce the
output file size, slower is smaller.

Note that it will select the 444P pixel format, which is a rather good
choice, but may be incompatible with some deficient players.

Newer codecs can be considered, like VP9, x265 or even AV1, but I have
not yet taken the time to get to know their quirks.


  Nicolas George

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