[mythtv-users] AC3 passthrough is failing in certain circumstances

[Matt Redmon]

----- Original Message ----- 
From: "Matt Redmon" <mythtv-user at comcast.net>
To: "Discussion about mythtv" <mythtv-users at mythtv.org>
Sent: Thursday, March 31, 2005 1:02 AM
Subject: [mythtv-users] AC3 passthrough is failing in certain circumstances


>I have a few video files that have Dolby AC3 encoding.  When I try to play 
>them with xine or gmplayer, they play back just fine in full 5.1 glory; 
>however mplayer does not do likewise.  mplayer will either spit out the 
>following message and exit or display the message and continue playing the 
>clip with no sound:
>
> ALSA lib setup.c:548:(add_elem) Cannot obtain info for CTL elem 
> (MIXER,'IEC958 Playback AC97-SPSA',0,0,0): No such file or directory
>
> I've tried many different variations of -ac hwac3, and -ao alsa:default 
> but all seem to either cause mplayer to exit or to play w/o sound.  Now, 
> the error message seems to indicate that there is no mixer control labeled 
> IEC958....   and that is true.  The problem is that I cannot seem to find 
> out why it is looking for that specific mixer.
>
> I have a 7NIF2 and am using the onboard soundcard.  Absolutely everything 
> else is working fine (2 channel and 5.1 surround on xine, 2 channel on 
> mplayer; in recordings, videos, dvds, etc.).  I'm running 0.17 from ATRPMs 
> on FC3.

I know I'm just replying to my message but I figured I'd post the solution I 
figured out.  Even though I used the website recommended on Jarod's site to 
set up my .asoundrc, it seems like mplayer did not like my "default" alsa 
device (even though both xine (alsa:default) and gmplayer ("alsa" and all 
settings set to "default") had no problem).  Passing -ao alsa:device=hw=0.2 
to mplayer solved this problem.

Thanks goes to Beirdo on #mythtv-users for telling me to "ask some mplayer 
experts" and Ikarus on #mplayer for telling me to "find out what ao gmplayer 
is using and copy that to mplayer..."  Eventually, the man page for mplayer 
(HUGE, btw) finally yielded the device= line.  If anybody has any idea why 
mplayer doesn't like my "default" alsa device, I'd be interested in figuring 
out (though I don't really care that much now that it is working properly).

Matt