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

[Matthieu Bouron]

On Wed, Jan 16, 2013 at 12:01:38PM +0100, Matthieu Bouron wrote:
> On Wed, Jan 16, 2013 at 10:37:03AM +0000, Paul B Mahol wrote:
> > On 1/16/13, Matthieu Bouron <matthieu.bouron at gmail.com> wrote:
> > > 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.
> > 
> > aligned to 2 byte boundary?
> 
> It seems to be. For example:
> ID3 data offset = 80988992
> ID3 data size = 151960
> Declared ID3 chunk size = 151959
> File offset after reading the ID3 data: 81140952 (which corresponds to the
> filesize)

The data itself is aligned however the chunk size is incorrect (or maybe i am
missing something).