[FFmpeg-devel] [PATCH] lavf/aiffdec: handle files with ID3 data larger than ID3 chunk size

[Michael Niedermayer]

On Wed, Jan 16, 2013 at 01:18:09AM +0100, Matthieu Bouron wrote:
> On Wed, Jan 16, 2013 at 12:34:31AM +0100, Michael Niedermayer wrote:
> > On Tue, Jan 15, 2013 at 10:49:01PM +0100, Matthieu Bouron wrote:
> > > ---
> > >  libavformat/aiffdec.c | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > > 
> > > diff --git a/libavformat/aiffdec.c b/libavformat/aiffdec.c
> > > index 8d466fa..b6a7946 100644
> > > --- a/libavformat/aiffdec.c
> > > +++ b/libavformat/aiffdec.c
> > > @@ -193,6 +193,7 @@ static int aiff_read_header(AVFormatContext *s)
> > >  {
> > >      int ret, size, filesize;
> > >      int64_t offset = 0;
> > > +    int64_t tag_size, tag_offset;
> > >      uint32_t tag;
> > >      unsigned version = AIFF_C_VERSION1;
> > >      AVIOContext *pb = s->pb;
> > > @@ -236,6 +237,7 @@ static int aiff_read_header(AVFormatContext *s)
> > >                  goto got_sound;
> > >              break;
> > >          case MKTAG('I', 'D', '3', ' '):
> > > +            tag_offset = avio_tell(pb);
> > >              ff_id3v2_read(s, ID3v2_DEFAULT_MAGIC, &id3v2_extra_meta);
> > >              if (id3v2_extra_meta)
> > >                  if ((ret = ff_id3v2_parse_apic(s, &id3v2_extra_meta)) < 0) {
> > > @@ -243,6 +245,11 @@ static int aiff_read_header(AVFormatContext *s)
> > >                      return ret;
> > >                  }
> > >              ff_id3v2_free_extra_meta(&id3v2_extra_meta);
> > > +            tag_size = avio_tell(pb) - tag_offset;
> > > +            if (tag_size > size) {
> > > +                av_log(s, AV_LOG_WARNING, "ID3 data is larger than ID3 chunk size\n");
> > > +                avio_seek(pb, tag_size - size, SEEK_SET);
> > > +            }
> > 
> > to which point do you try to seek here ?
> > this looks like you try to do a absolute seek with a relative value
> > 
> 
> Sorry for the messy patch :(, I didn't intend to seek anywhere but
> just to decrease the filesize variable according to the difference
> between tag_size and size.
> New patch attached.

so when the sizes mismatch a correct tag is at position after the
larger size ?

Iam trying to make sure that theres no failure in the ID3 parsing
that causes the size mismatch ...

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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