[FFmpeg-devel] [PATCH]Do not detect mpegts-in-mov as mov

[Carl Eugen Hoyos]

On Monday 22 October 2012 05:07:19 pm Michael Niedermayer wrote:
> On Mon, Oct 22, 2012 at 02:36:34PM +0000, Carl Eugen Hoyos wrote:
> > Michael Niedermayer <michaelni <at> gmx.at> writes:
> > > On Mon, Oct 22, 2012 at 11:11:53AM +0200, Carl Eugen Hoyos wrote:
> > > > Hi!
> > > >
> > > > Attached patch fixes ticket #987 for me.
> > >
> > > please check for mpegts like its done for mpegps OR remove the mpegps
> > > code and adjust the scores if this is possible. But dont mix the 2
> > > approuches
> >
> > mpeg-ts in mov start with a mdat atom, apart from that there is nothing
> > that reminds me of a mov (no other atom iirc). Both sample files we have
> > are detected by the mpegts probe code with a score of 100 when testing
> > 2048 bytes. But the mov detection is "quicker" although the files cannot
> > be read at all, only an error message is shown on ffmpeg -i input
> >
> > mpeg-ps in mov are real mov files with all kinds of atoms describing the
> > files and the mov demuxer was always able to read the files (it just
> > couldn't actually decode them).
> >
> > I don't think the same approach can be used for both type of strams.
>
> mdat is the only atom you can depend on in some movs,
> fate-suite/iv32/cubes.mov is one example (if you assume its bigger
> so its end is unavailable in the probe buffer)
>
> but the mdat atom is quite invalid, its size for example looks quite
> impossible. skiping such invalid atoms in building the score is fine
> and should i think fix the tciket too

New patch attached.

Please comment, Carl Eugen
-------------- next part --------------
diff --git a/libavformat/mov.c b/libavformat/mov.c
index ce4865d..f3ba59c 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -2879,7 +2879,11 @@ static int mov_probe(AVProbeData *p)
         case MKTAG('p','n','o','t'): /* detect movs with preview pics like ew.mov and april.mov */
         case MKTAG('u','d','t','a'): /* Packet Video PVAuthor adds this and a lot of more junk */
         case MKTAG('f','t','y','p'):
-            score  = AVPROBE_SCORE_MAX;
+            if (AV_RB32(p->buf+offset) >= 8) {
+                score = AVPROBE_SCORE_MAX;
+            } else {
+                score = FFMAX(score, AVPROBE_SCORE_MAX - 50);
+            }
             offset = FFMAX(4, AV_RB32(p->buf+offset)) + offset;
             break;
         /* those are more common words, so rate then a bit less */