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

Steven Adeff adeffs.mythtv at gmail.com
Tue Feb 21 03:21:08 UTC 2012


On Mon, Feb 20, 2012 at 9:57 PM, 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 ran the echo line and it "took", now when I play I see this, but I
can't figure out why it is forcing a downmix from 6 to 2 channel?

2012-02-20 19:12:52.576 AO: Sample rate 32000 is supported
2012-02-20 19:12:52.576 AO: Sample rate 44100 is supported
2012-02-20 19:12:52.576 AO: Sample rate 48000 is supported
2012-02-20 19:12:52.576 AO: Sample rate 88200 is supported
2012-02-20 19:12:52.576 AO: Sample rate 96000 is supported
2012-02-20 19:12:52.576 AO: Sample rate 176400 is supported
2012-02-20 19:12:52.576 AO: Sample rate 192000 is supported
2012-02-20 19:12:52.577 AO: Format signed 16 bit is supported
2012-02-20 19:12:52.577 AO: Format signed 24 bit MSB is supported
2012-02-20 19:12:52.577 AO: Format signed 32 bit is supported
2012-02-20 19:12:52.577 AO: 2 channel(s) are supported
2012-02-20 19:12:52.577 AO: 4 channel(s) are supported
2012-02-20 19:12:52.577 AO: 6 channel(s) are supported
2012-02-20 19:12:52.577 AO: 8 channel(s) are supported
2012-02-20 19:12:52.599 AO: Needs downmix from 6 -> 2 channels
2012-02-20 19:12:52.600 AO: Killing AudioOutputDSP
2012-02-20 19:12:52.600 AO: Original codec was AC3, signed 16 bit, 48
kHz, 6 channels
2012-02-20 19:12:52.600 AO: enc(0), passthru(0), canAC3(1), canDTS(1),
canLPCM(1), configured_channels(2), 2 channels supported(1)
2012-02-20 19:12:52.600 AO: Audio processing enabled
2012-02-20 19:12:52.600 AO: Opening audio device
'hdmi:CARD=NVidia_1,DEV=1' ch 2(6) sr 48000 sf signed 32 bit reenc 1
2012-02-20 19:12:52.601 ALSA: SetParameters(format=10, channels=2,
rate=48000, buffer_time=500000, period_time=4)


-- 
Steve
http://www.mythtv.org/wiki/User:Steveadeff
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