[mythtv-users] How to debug "no sound" ?

Fedor Pikus fpikus at gmail.com
Mon Jun 27 01:00:29 UTC 2005


I have a different soud card (SB Audigy), but I tried to do more or
less the same setup as you (change default to spdif from asound.conf)
and it was always one damn problem after another (or at the same
time). Finally, I got my answer from ALSA list: if the card is
properly configured in alsamixer, none of this stuff in asound.conf is
needed, default output will just work. I needed to mute "Optical
IEC958 Out". So get the latest ALSA, move aside asound.conf and
.asoundrc and fiddle with Alsamixer until it works (look for IEC958 or
digital jack controls).

Fedor

On 6/26/05, Michael T. Dean <mtdean at thirdcontact.com> wrote:
> John P Poet wrote:
> 
> > I just did a fresh install of Fedora Core 4.  Everything is working
> > great, except I get no sound out of Myth.
> >
> > I had a similar problem when I first installed my maudio sound card
> > under FC2.  All "other" programs would produce sound out the S/PDIF
> > jack just fine, but Myth was mute.  I thought I had finally figured
> > out what needed to go into my asound.conf file, to make Myth happy.  I
> > have tried using that exact same asound.conf file under FC4, but Myth
> > is still silent.
> >
> > What is weird, is that mplayer works with the S/PDIF out perfectly,
> > even when a asound.conf file does not exist.  All I have to do is use
> > "mplayer -ao alsa -ac hwac3" and it just works.
> 
> -ac hwac3 tells MPlayer to use AC-3 passthrough, so it's not using any
> information from your ALSA configuration file.  It's simply dumping the
> AC-3 stream from the DVD/video to your digital output.  This will work
> regardless of the config file.  (MPlayer without an /etc/asound.conf
> will play stereo sound on the analog outputs--unless the user running
> MPlayer defines an ~/.asoundrc .)
> 
> > Xine and aplay require the asound.conf file, however.  For Xine and
> > aplay, this asound.conf file is sufficient:
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > pcm.!default {
> >   type plug
> >   slave.pcm iec958
> > }
> >
> > pcm.ice1712 {
> >    type hw
> >    card 0
> >    device 0
> > }
> >
> > ctl.ice1712 {
> >    type hw
> >    card 0
> > }
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > With the above asound.conf, I can play both AC3 and stereo material
> > via the S/PDIF port using any program *except* Myth.
> 
> Basically just says to output to iec958 unless otherwise specified
> (remaps default output).
> 
> > Under FC2, I thought I had solved the problem by adding:
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > pcm.ice1712_spdif {
> >     type plug
> >     ttable.0.8 1 # S/PDIF left...Delta 9
> >     ttable.1.9 1 # S/PDIF right...Delta 10
> >     slave.pcm ice1712
> > }
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Funny...  That's a simplified version of the default definition for
> iec958 (see /usr/share/alsa/card/ICE1712.conf ).  I'd say try using
> ALSA:iec958 instead.  Even ALSA:default should work with a config file
> that remaps the default device (as above).
> 
> > And then telling Myth to use "ALSA:ice1712_spdif".  However, that does
> > not seem to be working under FC4.  I end up with this in my log:
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 2005-06-25 21:03:39.653 Using protocol version 17
> > adding pes stream at pid 0x31 with type 2
> > adding pes stream at pid 0x34 with type 129
> > 2005-06-25 21:03:42.696 libavformat type mpegts
> > 0: start_time: 4752.137 duration: 323.408
> > 1: start_time: 4752.094 duration: 323.407
> > stream: start_time: 52801.048 duration: 3593.896 bitrate=15577 kb/s
> > 2005-06-25 21:03:43.472 Stream #1 (audio track #0) is an audio stream
> > with 2 channels.
> > 2005-06-25 21:03:43.472 Auto-selecting AC3 audio track (stream #1).
> > 2005-06-25 21:03:43.472 Initializing audio parms from audio track #0.
> > 2005-06-25 21:03:43.603 Killing AudioOutputDSP
> > 2005-06-25 21:03:43.604 Opening audio device 'ice1712_spdif'.
> > 2005-06-25 21:03:43.612 in SetParameters(format=2, channels=2,
> > rate=48000, buffer_time=500000, period_time=125000)
> > 2005-06-25 21:03:43.613 get_buffer_size returned 6553
> > 2005-06-25 21:03:43.613 set_period_time_near returned 68250
> > 2005-06-25 21:03:43.613 get_period_size returned 3276
> > 2005-06-25 21:03:43.621 Audio fragment size: 4096
> > 2005-06-25 21:03:43.623 Audio Stretch Factor: 1
> > 2005-06-25 21:03:43.623 Ending reconfigure
> > 2005-06-25 21:03:43.624 kickoffOutputAudioLoop: pid = 13790
> > 2005-06-25 21:03:43.624 OutputAudioLoop: Play Event
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> > I am not even sure the problem has anything to do with the S/PDIF
> > port.  Using the envy24control utility, I see that when Myth is
> > "playing", no audio is being generated on *any* of the soundcard's
> > jacks.  When I use mplayer,xine or aplay, the envy24control utility
> > shows me that audio is being routed to the S/PDIF jack.  If I remove
> > the asound.conf file, and use aplay, envy24control shows me that the
> > audio is being routed to the first two analog jacks.
> 
> Because the config file changed the definition of the default device to
> output to the digital port.
> 
> > So, how do I debug this?  How can I figure out why all other programs
> > will send sound to my audio card, but Myth is mute?  Since Myth is not
> > generating any errors, I have no idea where to look.
> 
> HTH.
> 
> Mike
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> 


-- 
Fedor G Pikus (fpikus at gmail.com)
http://www.pikus.net
http://wild-light.com


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