[FFmpeg-devel] [PATCH 1/2] allow passing subtitles header between decoder and encoder

[Aurelien Jacobs]

On Tue, Oct 19, 2010 at 09:55:47PM +0200, Aurelien Jacobs wrote:
> On Tue, Oct 19, 2010 at 03:43:52PM +0200, Michael Niedermayer wrote:
> > On Sat, Oct 16, 2010 at 05:31:26PM +0200, Aurelien Jacobs wrote:
> > > ---
> > >  ffmpeg.c             |   11 +++++++++++
> > >  libavcodec/avcodec.h |    8 ++++++++
> > >  libavcodec/utils.c   |    2 ++
> > >  libavformat/utils.c  |    4 ++++
> > >  4 files changed, 25 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/ffmpeg.c b/ffmpeg.c
> > > index 4f59b2e..7622ccc 100644
> > > --- a/ffmpeg.c
> > > +++ b/ffmpeg.c
> > > @@ -2365,6 +2365,7 @@ static int transcode(AVFormatContext **output_files,
> > >          ost = ost_table[i];
> > >          if (ost->encoding_needed) {
> > >              AVCodec *codec = i < nb_output_codecs ? output_codecs[i] : NULL;
> > > +            AVCodecContext *dec = ist_table[ost->source_index]->st->codec;
> > >              if (!codec)
> > >                  codec = avcodec_find_encoder(ost->st->codec->codec_id);
> > >              if (!codec) {
> > > @@ -2373,6 +2374,15 @@ static int transcode(AVFormatContext **output_files,
> > >                  ret = AVERROR(EINVAL);
> > >                  goto dump_format;
> > >              }
> > > +            if (dec->subtitle_header) {
> > > +                ost->st->codec->subtitle_header = av_malloc(dec->subtitle_header_size);
> > > +                if (!ost->st->codec->subtitle_header) {
> > > +                    ret = AVERROR(ENOMEM);
> > > +                    goto dump_format;
> > > +                }
> > > +                memcpy(ost->st->codec->subtitle_header, dec->subtitle_header, dec->subtitle_header_size);
> > > +                ost->st->codec->subtitle_header_size = dec->subtitle_header_size;
> > > +            }
> > >              if (avcodec_open(ost->st->codec, codec) < 0) {
> > >                  snprintf(error, sizeof(error), "Error while opening encoder for output stream #%d.%d - maybe incorrect parameters such as bit_rate, rate, width or height",
> > >                          ost->file_index, ost->index);
> > > @@ -2728,6 +2738,7 @@ static int transcode(AVFormatContext **output_files,
> > >                  }
> > >                  av_fifo_free(ost->fifo); /* works even if fifo is not
> > >                                               initialized but set to zero */
> > > +                av_freep(&ost->st->codec->subtitle_header);
> > >                  av_free(ost->pict_tmp.data[0]);
> > >                  if (ost->video_resample)
> > >                      sws_freeContext(ost->img_resample_ctx);
> > > diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
> > > index 4bddbaa..ab3cbd9 100644
> > > --- a/libavcodec/avcodec.h
> > > +++ b/libavcodec/avcodec.h
> > > @@ -2744,6 +2744,14 @@ typedef struct AVCodecContext {
> > >       * - decoding: unused
> > >       */
> > >      int lpc_passes;
> > > +
> > > +    /**
> > > +     * Header containing style information for text subtitles.
> > > +     * - encoding: Set/allocated/freed by user (before avcodec_open())
> > > +     * - decoding: Set/allocated/freed by libavcodec (by avcodec_open())
> > > +     */
> > > +    uint8_t *subtitle_header;
> > > +    int subtitle_header_size;
> > >  } AVCodecContext;
> > >  
> > >  /**
> > 
> > The description should be enough to implement a decoder and a user app and
> > a subtitle renderer based on it. (some common sense and guessing not excluded)
> > but this seems too terse for that
> 
> OK. Updated patch.
> I think it should now be enough to implement anything related to this
> field, with a little bit of common sense and the ASS spec around.
> 
> > also are you sure every subtitle decoder will be able to set this by
> > avcodec_open() ?
> 
> Yes, sure. It wouldn't be very useful anyway to set it later on.
> I've already (started to) implement several decoders (SubRip,
> MicroDVD, Movtext...), and they fits well within this model.

Ping ?

Aurel