[FFmpeg-devel] skip multiple id3v2 headers

[David Byron]

Michael Niedermayer wrote:

> > could you explain what kind of conflict exists in there?
> > Its easier for discussion as you alraedy know than if
> > all interrested parties download the file and have to
> > analyze it

My primary concern isn't the actual metadata, though maybe it should be.
I'm concerned that av_read_frame returns packets that don't contain audio
data.  From this perspective it doesn't matter whether the additional id3v2
tags are parsed or not, and it seems simpler not to.  That's also what
ffmpeg does today so it seems like a good first step.

At the risk of being redundant, from an earlier message:

$ ./iterate_frames two_id3v2_with_fake_mpeg_small.mp3
Format detected only with low score of 24, misdetection possible!
"two_id3v2_with_fake_mpeg_small.mp3": frame 0: size 6906 byte(s)
"two_id3v2_with_fake_mpeg_small.mp3": frame 1: size 511 byte(s)
"two_id3v2_with_fake_mpeg_small.mp3": 2 frame(s), 7417 byte(s)

isn't correct, but 

$ ./iterate_frames two_id3v2_with_fake_mpeg_small.mp3
Format detected only with low score of 24, misdetection possible!
[mp3 @ 0x23da070] skipping additional id3v2 tag in
"two_id3v2_with_fake_mpeg_small.mp3"
"two_id3v2_with_fake_mpeg_small.mp3": frame 0: size 627 byte(s)
"two_id3v2_with_fake_mpeg_small.mp3": 1 frame(s), 627 byte(s)
 
is.

Vladimir Pantelic wrote:

> well, the tags could have differing artist/album/title
> etc.  field, which one should ffmpeg chose? Or export both
> sets?
> 
> One "rule" could be to pick up as much from all tags, but
> favoring earlier tags over later.

Yes, but to me this is complicated.  Since ffmpeg doesn't look at the
additional tags today (nor do other tools that I know about), I'd like to
keep it that way.  If we decide to dive in to the additional tags, is it OK
to implement separately?

-DB