[FFmpeg-devel] [PATCH 4/4] avidec: demux ASS and SRT tracks

[Aurelien Jacobs]

On Thu, Jul 08, 2010 at 12:52:54AM +0200, Michael Niedermayer wrote:
> On Thu, Jul 08, 2010 at 12:12:00AM +0200, Aurelien Jacobs wrote:
> > On Wed, Jul 07, 2010 at 09:27:30PM +0200, Michael Niedermayer wrote:
> > > On Tue, Jul 06, 2010 at 10:55:04PM +0200, Aurelien Jacobs wrote:
> > > > 
> > > > ---
> > > >  libavformat/avidec.c |   42 ++++++++++++++++++++++++++++++++++++++++--
> > > >  libavformat/utils.c  |    2 ++
> > > >  2 files changed, 42 insertions(+), 2 deletions(-)
> > > 
> > > >  avidec.c |   42 ++++++++++++++++++++++++++++++++++++++++--
> > > >  utils.c  |    2 ++
> > > >  2 files changed, 42 insertions(+), 2 deletions(-)
> > > > e528c97d940b4d16e1a96f56dd4686a3b8f3b83e  avidec-demux-ass-and-srt-track.patch
> > > > diff --git a/libavformat/avidec.c b/libavformat/avidec.c
> > > > index cdf8307..ac1e3b6 100644
> > > > --- a/libavformat/avidec.c
> > > > +++ b/libavformat/avidec.c
> > > > @@ -1138,6 +1170,12 @@ static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp
> > > >          ast2->packet_size=
> > > >          ast2->remaining= 0;
> > > >  
> > > > +        if (st2->codec->codec_type == AVMEDIA_TYPE_SUBTITLE
> > > > +            && !st2->codec->codec_tag) {
> > > > +            ast2->frame_offset = 0;
> > > > +            continue;
> > > > +        }
> > > 
> > > this doesnt feel correct, all sees go to point 0 ?
> > 
> > Well, actually gab2 subtitles are composed of one and only one
> > packet. After seeking, subtitles contained in this packet may be needed
> > (or not, but the avi demuxer has no way to know). So the only thing the
> > avi demuxer can do after a seek is to output this single packet.
> > Did I missed anything ?
> 
> this design is sick

Sure it is ! Definitely !

> > @@ -598,6 +598,13 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
> >                          ast->dshow_block_align = 0;
> >                      }
> >                      break;
> > +                case AVMEDIA_TYPE_SUBTITLE:
> > +                    st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
> > +                    st->codec->codec_id   = CODEC_ID_PROBE;
> > +                    st->need_parsing      = AVSTREAM_PARSE_FULL;
> > +                    av_set_pts_info(st, 64, 1, 1000);
> 
> > +                    url_fskip(pb, size);
> 
> what is in this data we skip?

Actually nothing !
I've checked it and there is never any data to skip at this point.
It seems to be a remainder of a copy/paste from the default case...
Yes, again... Fixed.
Now I've double checked and I'm pretty sure that there is no such dead
code left anymore.

Aurel
-------------- next part --------------
A non-text attachment was scrubbed...
Name: avidec-demux-ass-and-srt-track.diff
Type: text/x-diff
Size: 4568 bytes
Desc: not available
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20100708/544cc49a/attachment.diff>