[mythtv-users] mp4 files not playing audio

David Brodbeck gull at gull.us
Wed Nov 25 05:23:03 UTC 2009

Neil Salstrom wrote:
> I've got a number of mp4 files that I've made (encoded vhs tapes) and
> when playing I get no audio.  The files work fine in xine-vdpau.
> I'm running a self compiled 0.22-fixes. (Revision: 22867M)
> This is what I get in the log:
> 2009-11-18 19:47:29.361 TV: Attempting to change from None to Watching Video
> 2009-11-18 19:47:29.436 TV: StartPlayer(0, Watching Video, main) -- begin
> 2009-11-18 19:47:30.022 AFD: Opened codec 0x7f1fd0c8c9f0, id(MPEG4) type(Video)
> 2009-11-18 19:47:30.022 AFD: codec AAC has 2 channels
> 2009-11-18 19:47:30.022 AFD: Opened codec 0x7f1fd0b80e80, id(AAC) type(Audio)
> 2009-11-18 19:47:30.023 Opening audio device 'spdif'. ch 2(2) sr 96000
> 2009-11-18 19:47:30.023 Opening ALSA audio device 'spdif'.
> 2009-11-18 19:47:30.025 AudioOutput Error: Rate doesn't match
> (requested 96000Hz, got 48000Hz)
> 2009-11-18 19:47:30.026 AudioOutput Error: Unable to set ALSA parameters
> 2009-11-18 19:47:30.028 NVP(2): Disabling Audio, reason is: Unable to
> set ALSA parameters
> Do I need to re-encode the audio for these to play or is this a issued
> with something in mythtv?  Audio for everything else works fine.

The file has an audio sample rate of 96 kHz, but your audio output 
device can only handle 48 kHz.

I had the same problem with one of my systems.  Apparently the fix is to 
set up an asound.conf that tells ALSA to resample the audio on the fly. 
  Unfortunately the wiki reorganization broke all the links to how to do 
that in the mailing list archive.  I never did figure it out.  Since I 
was using analog instead of digital output I switched to using /dev/dsp 
instead of ALSA:default, avoiding all the nasty ALSA stuff.

More information about the mythtv-users mailing list