Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Is there any way to increase the ALSA buffer size?

When running this command:

ffmpeg -f alsa -ac 2 -i hw:1 -ar 44100 -b 64k output.mp3

I get a "ALSA buffer xrun" before my system locks up

Input #0, alsa, from 'hw:1':
  Duration: N/A, start: 2480.999037, bitrate: N/A
  Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
Output #0, mp3, to 'lastzzz.mp3':
    TSSE            : Lavf53.21.1
    Stream #0.0: Audio: libmp3lame, 44100 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
Press ctrl-c to stop encoding
[alsa @ 0x1c04660] ALSA buffer xrun.

Here is my version of ALSA:

pi@raspberrypi ~ $ cat /proc/asound/version
 Advanced Linux Sound Architecture Driver Version 1.0.25.

Just to make sure:

pi@raspberrypi ~ $ sudo apt-get install alsa
 Reading package lists... Done
 Building dependency tree
 Reading state information... Done
 Note, selecting 'alsa-base' instead of 'alsa'
 alsa-base is already the newest version.
 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
share|improve this question
"locks up"? I'd guess this is the cause of the xrun. – CL. Mar 21 '13 at 20:13
yes, running top in a separate window shows the cpu gradually increasing until it reaches 100% cpu – hinekyle Mar 21 '13 at 20:19
Which process eats the CPU? – CL. Mar 22 '13 at 7:48
the ffmpeg process has an increasing cpu load until it reaches 100% and I think it is because of the "Alsa buffer xrun" – hinekyle Mar 22 '13 at 12:20

You must log in to answer this question.

Browse other questions tagged .