#11411 HIGH 1.75-so: Audio recorded on 1.75 may switch channels or not play when output

Zarro Boogs per Child bugtracker at laptop.org
Tue Nov 8 13:24:33 EST 2011

#11411: Audio recorded on 1.75 may switch channels or not play when output
           Reporter:  greenfeld  |       Owner:  saadia       
               Type:  defect     |      Status:  assigned     
           Priority:  high       |   Milestone:  1.75-software
          Component:  distro     |     Version:  1.75-C1      
         Resolution:             |    Keywords:               
        Next_action:  diagnose   |    Verified:  0            
Deployment_affected:             |   Blockedby:               
           Blocking:             |  
Changes (by saadia):

 * cc: jon.nettleton at gmail.com (added)
  * status:  new => assigned


 The main question is whether the problem is not in playing back the
 recorded stream, but that the actual stream we record on this machine is
 in correct somehow.
 I have attached two files recorded.wav and edited.wav, and I explain below
 what they are.

 <<The following is basically copied from my "Audio observations" email>>
 The alternating between speakers after recording is actually a problem
 with the audio files recorded using "arecord -f dat", and has nothing to
 do with playing after recording.
 Here are two scenarios I have experienced:
  A. arecord -f dat -d 5 recorded.wav
      aplay -f dat recorded.wav
           Play this several times, usually alternates between left and
 right speaker OR
           Play this several times, sound alternates between no sound and
 stereo sound.
           This makes it sound like two streams either align or don't
 align, but have blank samples in between data.
 B. arecord -f dat -d 5 recorded.wav
     Transfer recorded.wav to Mac and edit with Audacity
      Replace left audio of recorded.wav with another sound, and save as
      Transfer sound back to XO and repeatedly run aplay -f dat edited.wav.
      Sound does not alternate between speakers any more. Left and right
 audio are distinct as expected.
      WaveFMT header is slightly different though. I have the two RIFF
 WaveFMT headers if any one wants to examine them.

Ticket URL: <http://dev.laptop.org/ticket/11411#comment:1>
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