[mythtv] Patch: VolumeControl update

[Jesper Sörensen]

Steven wrote:

>No problem, thanks for the patch, compiled just fine now.
>Looks like it fixes my pre-buffering problem using oss (/dev/dsp ).
>There was one a second or so after starting playback and then it ran
>fine for 10 minutes. Haven't had more time but will do more testing later.
>
>Using ALSA i get a mythfrontend crash when i start video playback.
>
>--------------
>2004-10-31 11:57:53 Initializing audio parms from stream #0.
>mythfrontend: mixer.c:485: snd_mixer_close: Assertie `mixer' faalde.
>--------------
>
>(in English this message would probably be "Assertion 'mixer' failed" :-)
>  
>

That looks very similar to the problems I had with Alsa, although that 
was with the pcm device...

*All* code using mixer_handle (and possibly some other variable too) 
needs to be guarded with a "if (mixer_handle == NULL) return;" or 
similar, or you have to make sure that the code does *not* try to use 
the mixer if it's not initialized. I'm unable to look into this right 
now but if you would care to take a look at it I'm sure the fix is 
pretty simple (check the volume functions in the bottom of 
libs/libmyth/audiooutputalsa.cpp).