[mythtv-users] Digital Audio Passthrough not working Mythtv 0.24-fixes

David Knight dlknight at sdf.lonestar.org
Tue Nov 9 19:33:20 UTC 2010

I've just upgraded to Mythtv 0.24-fixes and I'm glad the build process was
as simple as for 0.23.1 :) Just a few modifications required to the

Now in Mythtv 0.23.1 I had the following options configured which
outputted audio to the analog output of my soundcard and also the optical
audio out into my DD/DTS amplifier. This worked great and I could listen
to all sources via my amplifier with DD/DTS being output when the source
supported it.

Audio output device = "ALSA:default"
Passthrough output device: "ALSA:iec958 {AES0: 0x02}"
Max Audio Channels: 5.1
Upmix: Passive
Enable AC3 to SPDIF passthrough = Enabled
Enable DTS to SPDIF passthrough = Enabled
Advanced Audio Configuration = Disabled
Use internal volume controls = Enabled

In Mythtv 0.24 the same settings do not work with DD/DTS, instead I get no
sound and stuttery video which utimately stops playing after 5-10 seconds
with a buffer error.

If I change the audio output device in Mythtv 0.24 to "ALSA:iec958 {AES0:
0x02}" then playback through the spdif interface works fine although I no
longer having the ability to output analog audio from the soundcard or
control the volume of stereo PCM audio with the internal volume controls.
Does anyone have any ideas why this isn't working?


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