alsa-utils' arecord bug: lots of *.wav files, ignoring --duration parameter



I ran into a rather funny bug recently – when recording audio on an RPi with Raspbian Jessie via an external USB sound card, arecord doesn’t stop recording after a period of time specified by --duration flag, but keeps running and filling files *-01.wav, *-02.wav, etc. with garbage data. Googling doesn’t return a solution, except an obvious one to killall -KILL arecord. USB microphones are also affected.

Since I have another RPi running Wheezy and showing no symptoms of the bug (and being free of systemd malware ;), the bug is likely in arecord itself. Jessie from 2016-05-27-raspbian-jessie.img includes alsa-utils of version 1.0.28 and arecord --version returns the same. There is a report indicating that 1.0.27 from Arch is buggy as well. Wheezy includes alsa-utils of version 1.0.25 and is free of this bug, so it was introduced in either 1.0.26 or 1.0.27.

A temporary solution is to downgrade alsa-utils to 1.0.25 or lower as follows:

  • add Wheezy repos: echo "deb wheezy main contrib non-free rpi" >> /etc/apt/sources.list
  • update the sources: sudo apt-get update
  • check available versions: sudo aptitude versions alsa-utils (this should indicate that the older version of alsa-utils is now available)
  • install the available older version: sudo apt-get install alsa-utils=1.0.25-4
  • verify that arecord now works fine, e.g.: arecord -D plughw:1,0 -r 44100 -f cd -d 5 -vv ~/test.wav (recording should stop after 5 seconds)
  • revert the changes made to /etc/apt/sources.list (comment out the newly added line) and update the sources again: sudo apt-get update