#1041114 sox error and audio glitch when -t not specified and libsox-fmt-pulse is not installed

Package:
sox
Source:
sox
Description:
Swiss army knife of sound processing
Submitter:
Chris Bainbridge
Date:
2026-01-15 11:21:01 UTC
Severity:
normal
#1041114#5
Date:
2023-07-14 21:59:01 UTC
From:
To:
Dear Maintainer,

When `-t` is not specified then sox attempts to probe the audio driver
as described at
https://groups.google.com/g/linux.debian.bugs.dist/c/jCqdwFWPUKk/m/xi1AThVtMwkJ

According to the list in that discussion, pulseaudio is the first driver
to be probed on Linux. If libsox-fmt-pulse is not installed, then the
probe fails with the error `play WARN alsa: can't encode 0-bit Unknown
or not applicable`, and there is an audible pop glitch before the actual
audio is played.

$ play -t raw -r 48k -e signed -b 16 -c 1 dummy
play WARN alsa: can't encode 0-bit Unknown or not applicable

(note libsox-fmt-pulse was not installed by default on my system, the
alsa driver was, so this warning and audio glitch would occur every
time by default)
#1041114#14
Date:
2026-01-15 10:56:21 UTC
From:
To:
close 1041114 1.4.7.0.3+ds1-1
thanks

The pulseaudio plugin is now always available.

Cheers