[mythtv-users] alsa 1.0.24, 0.24.2-fixes, ubuntu lucid, hdmi audio, AC3/DTS not working

Jean-Yves Avenard jyavenard at gmail.com
Tue Feb 21 03:23:01 UTC 2012


Hi

On 21 February 2012 13:57, Steven Adeff <adeffs.mythtv at gmail.com> wrote:
> upgraded a machine to 1.0.24 which is connected to a denon receiver
> with HDMI and I'm trying to get the audio working.
>
> it works fine in mplayer with
> -ao alsa:device=plughw=1.7
> for ac3, dts, and stereo PCM
>
> in Myth though, I can only seem to get stereo audio to work.
> I scan audio devices and try the various
> ALSA:hdmi:CARD=NVidia_1,DEV=0
> ALSA:hdmi:CARD=NVidia_1,DEV=1
> ALSA:hdmi:CARD=NVidia_1,DEV=2
> ALSA:hdmi:CARD=NVidia_1,DEV=3
>
> in the frontend log, with audio logging enabled, when I play an ac3
> recording using ALSA:hdmi:CARD=NVidia_1,DEV=1 which should be 1,7 I
> get this:
>
> 2012-02-20 18:43:56.522 AFD: Opened codec 0x9d055420, id(MPEG2VIDEO) type(Video)
> 2012-02-20 18:43:56.522 AFD: codec AC3 has 6 channels
> 2012-02-20 18:43:56.523 AFD: Opened codec 0x9bd78a80, id(AC3) type(Audio)
> 2012-02-20 18:43:56.523 AFD: codec AC3 has 1 channels
> 2012-02-20 18:43:56.524 AFD: Opened codec 0x9d38de30, id(AC3) type(Audio)
> 2012-02-20 18:43:56.643 AO: Opening audio device
> 'hdmi:CARD=NVidia_1,DEV=1' ch 6(6) sr 48000 sf signed 16 bit reenc 1
> 2012-02-20 18:43:56.645 ALSA, Error: Setting hardware audio buffer size to 320
> 2012-02-20 18:43:56.646 ALSA, Error: Error opening
> /proc/asound/card1/pcm7p/sub0/prealloc: Permission denied.
> 2012-02-20 18:43:56.646 ALSA, Error: Try to manually increase audio
> buffer with: echo 320 | sudo tee
> /proc/asound/card1/pcm7p/sub0/prealloc
> 2012-02-20 18:43:56.646 ALSA, Error: Unable to sufficiently increase
> ALSA hardware buffer size - underruns are likely
> 2012-02-20 18:43:56.817 AudioPlayer: Enabling Audio
>
> but the receiver only receives the left and right channel and it says
> it's in PCM
>
> if I try the others I don't get anything.
>
> anyone have any idea what's going on?

I do ...

But before I go on making guesses, re-run the same thing with -v audio..

There I will be able to tell you for sure...

The thing I can tell for sure is that your amp doesn't seem to play 6
channels PCM..
Check this:
http://www.mythtv.org/wiki/User_Manual:HDAudioPassthrough#Checking_your_TV_.2F_Amplifier_.2F_Audio_Processor_capabilities

in particular, report the ELD data shown for your system...


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