[mythtv-users] Unable to get video playback in MythTV

[Michael T. Dean]

Jason Slaughter wrote:

> I'm using the arrow keys to select the device, and when I go *back* to 
> the configuration screen my choice has changed. Just as a sanity check 
> I even checked the MySQL database and /dev/dsp1 is definite stored in 
> the database. Despite all of this, when I hit "Watch TV" the console 
> output shows "Opening OSS audio device '/dev/dsp'." :I
>
> It looks like Brian and I are having exactly the same problem, so I'll 
> add what I've done so far. I've installed ALSA, and it is working 
> fine. I've got sound in aplay, tvtime, and xawtv. MythTV still isn't 
> working with sound however. When I hit "watch TV" the picture comes 
> up, but no sound. Sometimes changing channels freezes as well. The 
> console output shows the following:
>
> 2004-10-18 09:50:22 Changing from WatchingLiveTV to None
> 2004-10-18 09:50:22 Changing from None to None
> 2004-10-18 09:54:35 Using protocol version 13
> 2004-10-18 09:54:37 Opening OSS audio device '/dev/dsp'.
> 2004-10-18 09:54:37 Audio fragment size: 4096
> 2004-10-18 09:54:37 Using XV port 53
> 2004-10-18 09:54:37 Changing from None to WatchingLiveTV
> 2004-10-18 09:54:37 Using realtime priority.
> 2004-10-18 09:54:40 Audio buffer overflow, audio data lost!
> 2004-10-18 09:54:43 Audio buffer overflow, audio data lost!
> 2004-10-18 09:54:45 Audio buffer overflow, audio data lost!
> 2004-10-18 09:54:48 Audio buffer overflow, audio data lost!
>
> I see two things wrong here. The first is that it's trying to open the 
> *OSS* audio device, when I'm running alsa now (and no oss emulation yet).

In spite of the fact that you're running ALSA, Myth is configured to use 
OSS.  However, since ALSA does a great job of emulating OSS (with or 
without the ALSA OSS modules installed), it can work in this situation.  
As a matter of fact, OSS audio in MythTV is much more mature/much more 
stable than ALSA audio, so loading the ALSA OSS modules and using OSS 
emulation is the preferred approach.  The only way to use ALSA is to 
change the audio device to ALSA:device-name (at which point you *should* 
create a proper .asoundrc).  Since you're using /dev/dsp#, you're using OSS.

Try enabling the ALSA OSS modules and see if that works.  There's no 
reason not to use them...

> The second is that it's still trying to open /dev/dsp even though the 
> setup program and the DB have "/dev/dsp1". 

? Don't know why that would be.  Perhaps it's a misleading message in 
the log file.  (If your database shows the correct value, it should 
work.)  Do you have multiple backends?  If so, are you sure you're 
looking at the right backend?

Mike