Запускаю командой
ffmpeg -f alsa -ac 2 -i hw:0,0 -acodec pcm_s16le -f x11grab -s 1280x800 -r 25 -i :0.0 -vcodec qtrle screencast.mov
Получаю выхлоп
ffmpeg version 0.8.3-4:0.8.3-0ubuntu0.12.04.1, Copyright (c) 2000-2012 the Libav developers
built on Jun 12 2012 16:52:09 with gcc 4.6.3
*** THIS PROGRAM IS DEPRECATED ***
This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
[alsa @ 0x18987a0] Estimating duration from bitrate, this may be inaccurate
Input #0, alsa, from 'hw:0,0':
Duration: N/A, start: 5511.948419, bitrate: N/A
Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
[x11grab @ 0x18abc40] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1280 height: 800
[x11grab @ 0x18abc40] shared memory extension found
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 142 (MIT-SHM)
Minor opcode of failed request: 4 (X_ShmGetImage)
Serial number of failed request: 11
Current serial number in output stream: 11
Не знаю как чинить.