[mythtv-users] ALSA 1.0.25 and broken AC3 passthrough?

Jean-Yves Avenard jyavenard at gmail.com
Mon Feb 6 12:40:47 UTC 2012


Hi there.

Could anyone try upgrading to the recently released ALSA 1.0.25
drivers and libraries and try playing some AC3 content (digital
passthrough) and see if it plays okay?

Posted on the alsa mailing list:

Today, I installed 1.0.25 drivers and libraries...
AC3 passthrough is completely broken.

My hardware: NVidia GT430, hdmi output
Device used:
hdmi:CARD=NVidia,DEV=0,AES0=6,AES1=0x82,AES2=0x00,AES3=0x01
on Ubuntu 10.04 LTS (but using manually built alsa)

It makes the application hangs or behaves incorrectly. All the time
broken, no matter which app.
Reverting back to 1.0.24 fixes the problem

I haven't delved much into it yet,
MythTV (I am the audio developer) after opening the audio device in
passthrough mode, trying to write audio on the pcm just hangs and
result in an I/O error after a little while
snd_pcm_writei returns an error (not immediately)
snd_pcm_state(pcm_handle) returns 3, snd_strerror(err) returns
"Input/output error"

mplayer just hangs...

nothing obvious in the logs, audio device opens okay, i can't say I
notice much difference in opening the device, allocating fragment and
the lot.

Anyone else has seen this?

Jean-Yves


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