[FFmpeg-devel] improved DV probe score patch BROKES detecting 1-frame DV

[Reimar Döffinger]

On Fri, Sep 25, 2009 at 04:01:19PM +0200, Michael Niedermayer wrote:
> On Fri, Sep 25, 2009 at 03:15:24PM +0200, Reimar D?ffinger wrote:
> > On Fri, Sep 25, 2009 at 02:43:51PM +0200, Michael Niedermayer wrote:
> > > On Fri, Sep 25, 2009 at 02:18:41PM +0200, Reimar D?ffinger wrote:
> > > > E.g. this change makes it work:
> > > > Index: libavformat/mpeg.c
> > > > ===================================================================
> > > > --- libavformat/mpeg.c  (revision 20013)
> > > > +++ libavformat/mpeg.c  (working copy)
> > > > @@ -78,7 +78,7 @@
> > > >  
> > > >  //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d len:%d\n", sys, priv1,
> > > >  //pspack,vid, audio, p->buf_size);
> > > >      if(sys>invalid && sys*9 <= pspack*10)
> > > > -        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg
> > > > +        return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4-1; // +1 for .mpg
> > > 
> > > i would prefer if the scores would not be decreased below 25 to workaround
> > > the inefficiency of the dv probe that we know how to improve.
> > 
> > Sorry to be snarky but I would prefer for the MPEG probe function not to
> > grab the world for itself,
> 
> maybe we should test how bad the various <=25 probes are with probetest and
> then consider to reassign scores based on that. If above really is that
> often causing false positives then i surely agree with reducing its score

I don't _really_ know if it's often it is a problem, though given how
fast (less than a week?) we got a bug report about this it seems likely
the MPEG probe is not that difficult to trigger even for a score 25 one.
Note that I also sent this patch so it is clear which of the checks
causes this issue, in case something might be wrong/suboptimal with that
specific one.