[mythtv-users] Audio trouble with MythMusic

Michael T. Dean mtdean at thirdcontact.com
Fri Aug 12 02:30:17 UTC 2005

Dave wrote:

>I have ALSA:iec958 set as my output device in MythTV and MythMusic. 
>In MythTV it works great, I can get 5.1 SPDIF audio to my receiver.
>However, when I try MythMusic, I get:
>2005-08-11 21:26:58.103 Opening audio device 'iec958'.
>2005-08-11 21:26:58.104 Rate doesn't match (requested 44100Hz, got 48000Hz)
>2005-08-11 21:26:58.104 Unable to set ALSA parameters
>The funny thing (to me at least), is that alsaplayer works ok with the
>same file:
>alsaplayer --verbose -d iec958 it.ogg
>Anyone have any ideas on the rate mismatch?
Your soundcard (like most--if not all--others) requires 48KHz PCM for 
S/PDIF.  When you tried to play your song in MythMusic, you chose a file 
(like most audio files ripped from CD's, since CD's themselves use 
44.1KHz sample rate) that has 44.1KHz sample rate.  Therefore, it won't 
play through your S/PDIF.

So, you simply need to use the plug plugin to do automatic sample 
rate/channel/format conversion.  See the DigitalSoundHowTo ( 
http://mythtv.info/moin.cgi/DigitalSoundHowTo ).

The AlsaPlayer test is an apples/oranges comparison, as AlsaPlayer tries 
to be smarter than the user.  If you try aplay, on the other hand, it 
would be a fair comparison (and will also fail to play the file on the 
requested device).


More information about the mythtv-users mailing list