[FFmpeg-devel] [PATCH] Fix Ogg data_offset computation.

[Aaron Colwell]

I see what your saying. I think you might be right. I'll test this and
see if it works out for me. Thanks for the help. I appreciate it.

Aaron

Ok, let me explain some things that confuse me so about this.
> The demuxer assumes that the first non-header packet means no
> more header packets will follow.
> Thus if this !os->header condition triggers we should not read
> further in read_headers because we already have all headers.
> As far as I can tell, by resetting ogg->headers that read_headers
> loop might go on for a long time, and if there is another
> packet from this same stream the first one will just be discarded.
> I think that the code instead should be (the "if (!ogg->headers)"
> condititon should no longer be needed):
>
> av_assert0(!ogg->headers);
> ogg->headers = 1;
> s->data_offset = os->sync_pos;
> for (i = 0; i < ogg->nstreams; i++) {
>    struct ogg_stream *cur_os = ogg->streams + i;
>    // all header packets must be complete before the first non-
>    // header one, so everything that follows must be non-header
>    cur_os->header = 0;
>    // if we have a partial non-header packet, its start is
>    // obviously at or after the data start
>    if (cur_os->incomplete) {
>        av_assert0(cur_os->sync_pos >= 0);
>        s->data_offset = FFMIN(s->data_offset, cur_os->sync_pos);
>    }
> }
>
> Completely untested of course.
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