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

[Matthieu Bouron]

On Wed, Jan 16, 2013 at 02:37:19AM +0100, Michael Niedermayer wrote:
> 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 ?

No, the samples i have have the ID3 chunk at the end of the file and the ID3
data is larger than the declared ID3 chunk size by one byte.

Unfortunately, i can't provide any samples since those are files i
bought from on online music store.

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