[mythtv] sound + xvmc + livetv = problem, why?

Isaac Richards ijr at case.edu
Mon Jan 30 00:27:55 UTC 2006


On Sunday 29 January 2006 18:55, Daniel Kristjansson wrote:
> On Sun, 2006-01-29 at 17:17 -0500, Isaac Richards wrote:
> > On Sunday 29 January 2006 16:58, Daniel Kristjansson wrote:
> > > On Sun, 2006-01-29 at 16:40 -0500, Isaac Richards wrote:
> > > > On Sunday 29 January 2006 14:38, Daniel Kristjansson wrote:
> > > > > I've been looking at ticket #774 a little more closely since it
> > > > > seems to be effecting more users and it makes the EPIA pretty
> > > > > useless as a frontend in LiveTV mode.
> > > >
> > > > Does pausing for a few seconds, then unpausing help at all?
> > >
> > > It has been reported to help, but it hasn't made any difference in
> > > my testing.
> >
> > Well, I'd play with the extra audio buffering code - you should be able
> > to force it to decode more audio and defer video decoding with that. 
> > Logic of how much extra audio to decode is around line 2210 of
> > avformatdecoder.cpp (the 'storevideoframes' bit).  It just compares
> > timestamps, fairly simple stuff..
>
> Hey, it looks like the problem may be right there, extra audio buffering
> is not set if the decoder is recreated but not the video output method.
> For some reason this decoder setting is being set in NVP::InitVideo
> instead of NVP::OpenFile where all the other decoder options are set..

I believe it was set there because we don't want it for the null videoout 
method. I would've sworn it was always forced on for both types of xvmc, too, 
but I don't see that anywhere.

There's a place in avformatdecoder that seems like it'd be disabling the 
forced on extra buffering as well, in InitVideoCodec.  Might want to check 
that that's not causing problems either.

Isaac


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