choppy dsp (mono/stereo problem?)

Carl McTague mctague at
Wed Jun 18 09:43:10 PDT 2003

Hi, I'm trying to use ohphone, but am having a low-level problem with
sound-in; it sounds choppy; it sounds as though a mono signal encoded
in stereo with a silent channel is being misinterpreted as a single
mono stream.  For example, if the sound was abcd it plays back
a0b0c0d0 (where 0 is silence).  I can reproduce the same choppyness by

  wavrec test.wav

(installed from the ports).  But in this case, I can fix it by doing

  wavrec -S test.wav

where -S "set[s] stereo mode."  I get the same thing within xwave by
changing between mono and stereo record modes.

Furthermore, I if I do

  cat /dev/audio > test.raw
  cat test.raw > /dev/audio

I get a similar (but somewhat more severe) choppiness.

Any ideas?  I'm using 4.7-RELEASE and

  (carl at xi:~) cat /dev/sndstat
  FreeBSD Audio Driver (newpcm)
  Installed devices:
  pcm0: <Intel 82801CA (ICH3)> at io 0xd800, 0xdc80 irq 11 bufsz 16384 (1p/2r/0v channels duplex)


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