[mythtv-users] 32khz AC3 Streams was: Sound problem with AC3 passthrough

[Steve Hodge]

On 6/15/06, Rob Baumstark <rbaumstark at gmail.com> wrote:
> On 6/14/06, Steve Hodge <stevehodge at gmail.com> wrote:
> > On 6/15/06, Rob Baumstark <rbaumstark at gmail.com> wrote:
> > > I'm convinced that this is either an issue with MythTV's AC3 handling
> > > (and there's discussion over in the -dev list about passthrough too,
> > > though it doesn't touch this particular issue with it), and/or an
> >
> > But the same issue occurs with mplayer, right? So it's not MythTV at fault...
>
> Yes - but mplayer is dumb.  It plays the file you give it, out the
> video device you specify, and out the audio device you specify.
>
> MythTV on the other hand is smart.  It does all kinds of things for
> me, from finding/flagging commercials, resolving conflicts with
> recording schedules, etc.  It should IMHO also be able to decide when
> to pass AC3 to my receiver, and when to process the audio and give the
> receiver PCM.

Someone will need to write the code though. If ALSA exposes the fact
that the hardware can't handle 32kHz AC3 then MythTV should be able to
automatically figure out when it needs to decode AC3 and output PCM,
otherwise we'd need a configuration option along the lines of
"passthrough AC3, unless it's 32kHz".

> With mplayer, I expect to have to tweak the options I give it every
> time I type out the command-line - with myth, I expect once I've
> setup/tweaked it to my liking, to just work.

Sure, but the functionality you need doesn't exist in MythTV. Someone
needs to write it.

Steve