[mythtv] [mythtv-commits] Ticket #1104: multi channel audiosupport

[Matt]

On Nov 5, 2007 7:11 PM, Janne Grunau <janne-mythtv at grunau.be> wrote:
> On Tuesday 06 November 2007 00:37:01 Mark Spieth wrote:
> > >
> > > I had quick look at mythtv_ac3.29.patch and noticed a few things:
> > >
> > > -the #if MAXCHANNELSELECT in avformatdecoder is ugly and seems to
> > > be unneeded
> >
> > I think it is needed. what it does is allow maxchannels generated by
> > the audio decoder to be tested and used further downstream where the
> > number of channels available configures the output device.
> > It lets the codec do max channels that the play can cope with. this
> > can be different in mythcommflag vs alsa.
>
> Maybe I haven't looked good enough but I've seen it only once defined in
> avformatdecoder. Just for debugging the code it imho too intrusive.
>
> > > -are the changes to libavcodec/ac3dec really necessary? if yes, can
> > > you try to get them upstream?
> >
> > only change to ac3 is now in ac3_parser.c to make ac3_sync globally
> > exported (remove static).
>
> that change in the parser is ok.
>
> > a52dec.c had extensive changes and has been removed so it doesnt
> > matter anymore.
>
> oh, I mixed it up.
> a52dec.c was just renamed to liba52.c but it will probably go away
> sooner than later.
>
> > this was mainly for channel ordering to make it the
> > same as ac3dec and dtsdec. not sure about the channel ordering in the
> > new dtsdec replacement (dca?).
>
> libdts or libdca support was removed. libavcodec has a native dca
> decoder. I have just looked briefly at it. see below
>
> > > -you're duplicating the DTS parsing functions in libmyth
> >
> > this is true. it needs to be defined in libmyth so perhaps avf can
> > use it from there.
>
> yes, even if it feels strange to have those codec/parser related
> functions in libmyth. but the same goes for the avcodec dependency.
>
> > there may even be code to do the same thing in
> > lavc now but after a quick look dca doesnt seem to have a sync.
>
> yeah, I look at it too during the merge to get rid of the dts parsing in
> avformatdecoder.
>
> > funnily enough I was doing some tests on the latest patch only a
> > couple of hours before you committed :-)
> > also I noticed that with libfaad and libfaac enabled, things dont
> > link properly for me.
>
> I found that too and I'm fixing it now.
>
> > also LIBA52 in this seems superfluous since a52dec is gone.
>
> see above
>
> > an OT question about how mpeg timestamp wrap is now handled.
>
> I'll need sleep to answer this
>
> Janne
>
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I see Mark's cleaned up the patch against current head.  I'd be a
happy camper if this were to actually be merged in sooner than later.
Primarily for me, I time stretch just about everything, and having it
down-convert to 2-CH analog from my HD recordings or DVDs is really
annoying.

Thanks for you hard work on this Mark!

Thanks!
Matt