[mythtv-commits] Ticket #10081: ALSA: Distorted 24bit playback

[MythTV]

#10081: ALSA: Distorted 24bit playback
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     Reporter:  mac20xx@…              |      Owner:  jyavenard
         Type:  Bug Report - General   |     Status:  new
     Priority:  minor                  |  Milestone:  unknown
    Component:  MythTV - Audio Output  |    Version:  0.24.1
     Severity:  medium                 |   Keywords:
Ticket locked:  0                      |
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 If the decoded audio-data is stored in upper 24bits of 4 bytes alsa output
 is distorted.

 see http://lkml.indiana.edu/hypermail/linux/kernel/0806.3/0134.html

 Changing audiooutputalsa.cpp fixed it at least for flac and wave files on
 my system.

 bool AudioOutputALSA::OpenDevice()
 {

 ...

     switch (output_format)
     {
         case FORMAT_U8:  format = SND_PCM_FORMAT_U8;    break;
         case FORMAT_S16: format = SND_PCM_FORMAT_S16;   break;
         // The data is stored in upper 24bits of 4 bytes
         case FORMAT_S24: format = SND_PCM_FORMAT_S32;   break;
         case FORMAT_S32: format = SND_PCM_FORMAT_S32;   break;
         case FORMAT_FLT: format = SND_PCM_FORMAT_FLOAT; break;
         default:
             Error(QString("Unknown sample format:
 %1").arg(output_format));
             return false;
     }

 ...

 }

 If all audio-decoders use the upper 24bits of 4 bytes for their data
 everything should work

-- 
Ticket URL: <http://code.mythtv.org/trac/ticket/10081>
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