[MPlayer-dev-eng] [PATCH] prefer lavf pva and lmlm4 demuxers

[Reimar Döffinger]

Hello,
On Tue, Jun 03, 2008 at 09:25:46PM +0200, Ivo wrote:
> On Tuesday 03 June 2008 20:21, Reimar Döffinger wrote:
> > On Tue, Jun 03, 2008 at 07:14:08PM +0200, Ivo wrote:
> > > > I am not sure if there is a native alternative to these, so the real
> > > > criteria is: If you are sure that the auto-detection of these formats
> > > > is (almost) 100% reliable.
> > >
> > > I have been fairly cautious with the probe functions. lmlm4's probe
> > > function returns either AVPROBE_SCORE_MAX/2 or 0 and pva returns either
> > > AVPROBE_SCORE_MAX/3, /5 or 0.
> >
> > That you used AVPROBE_SCORE_MAX/2 and similar is more a reason for
> > concern, since that would indicate that the autodetection is _not_
> > reliable. And a score of "only" AVPROBE_SCORE_MAX/2 helps nothing at
> > all if the format is not one recognized by avformat, then anything > 0
> > has exactly the same effect.
> > If you only want to make them default over the internal ones, you can
> > just move the native ones lower in the demuxer list.
> 
> I see. That'll work for LMLM4 (at least with the sample files) but it fails 
> with PVA files. Those get misdetected as MPEG-ES by MPlayer.
> 
> How should I proceed?

Ideally: Fix MPEG-ES detection by native demuxer ;-).
But the pva check seems reasonably safe to me (4 bytes at fixed position
directly at start, 3 of which must match exactly and one has two valid
values).
I did not bother to check how safe the lmlm4 test is, but it seems quite
complex to me.

Greetings,
Reimar Döffinger