[FFmpeg-devel] [PATCH] avformat/assdec: output ASS packets

[wm4]

On Fri, 19 Sep 2014 20:49:49 +0200
Clément Bœsch <u at pkh.me> wrote:

> After this the order from the original file is stored through readorder
> when doing ffmpeg -i input.ass -c copy output.mkv.
> 
> And now that the ASS muxer honors the ReadOrder, extracting the ass back
> (without transcoding) restores the original order.
> 
> TODO: micro bump
> ---
>  libavformat/assdec.c | 25 ++++++++++++++++++-------
>  1 file changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/libavformat/assdec.c b/libavformat/assdec.c
> index a5f792a..f176565 100644
> --- a/libavformat/assdec.c
> +++ b/libavformat/assdec.c
> @@ -29,6 +29,7 @@
>  
>  typedef struct ASSContext {
>      FFDemuxSubtitlesQueue q;
> +    unsigned readorder;
>  } ASSContext;
>  
>  static int ass_probe(AVProbeData *p)
> @@ -52,18 +53,26 @@ static int ass_read_close(AVFormatContext *s)
>      return 0;
>  }
>  
> -static int read_ts(const uint8_t *p, int64_t *start, int *duration)
> +static int read_dialogue(ASSContext *ass, AVBPrint *dst, const uint8_t *p,
> +                         int64_t *start, int *duration)
>  {
>      int64_t end;
> +    int layer, pos;
>      int hh1, mm1, ss1, ms1;
>      int hh2, mm2, ss2, ms2;
>  
> -    if (sscanf(p, "%*[^,],%d:%d:%d%*c%d,%d:%d:%d%*c%d",
> +    if (sscanf(p, "Dialogue: %d,%d:%d:%d%*c%d,%d:%d:%d%*c%d,%n", &layer,

What about "Comment: " lines?

>                 &hh1, &mm1, &ss1, &ms1,
> -               &hh2, &mm2, &ss2, &ms2) == 8) {
> +               &hh2, &mm2, &ss2, &ms2, &pos) >= 9) {
>          end    = (hh2*3600LL + mm2*60LL + ss2) * 100LL + ms2;
>          *start = (hh1*3600LL + mm1*60LL + ss1) * 100LL + ms1;
>          *duration = end - *start;
> +
> +        av_bprint_clear(dst);
> +        av_bprintf(dst, "%u,%d,%s", ass->readorder++, layer, p + pos);
> +        while (dst->str[dst->len - 1] == '\r' ||
> +               dst->str[dst->len - 1] == '\n')
> +            dst->str[--dst->len] = 0;
>          return 0;
>      }
>      return -1;
> @@ -88,7 +97,7 @@ static int64_t get_line(AVBPrint *buf, FFTextReader *tr)
>  static int ass_read_header(AVFormatContext *s)
>  {
>      ASSContext *ass = s->priv_data;
> -    AVBPrint header, line;
> +    AVBPrint header, line, rline;
>      int header_remaining, res = 0;
>      AVStream *st;
>      FFTextReader tr;
> @@ -99,12 +108,13 @@ static int ass_read_header(AVFormatContext *s)
>          return AVERROR(ENOMEM);
>      avpriv_set_pts_info(st, 64, 1, 100);
>      st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
> -    st->codec->codec_id   = AV_CODEC_ID_SSA;
> +    st->codec->codec_id   = AV_CODEC_ID_ASS;
>  
>      header_remaining = INT_MAX;
>  
>      av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);
>      av_bprint_init(&line,   0, AV_BPRINT_SIZE_UNLIMITED);
> +    av_bprint_init(&rline,  0, AV_BPRINT_SIZE_UNLIMITED);
>  
>      for (;;) {
>          int64_t pos = get_line(&line, &tr);
> @@ -125,9 +135,9 @@ static int ass_read_header(AVFormatContext *s)
>              int duration = -1;
>              AVPacket *sub;
>  
> -            if (read_ts(line.str, &ts_start, &duration) < 0)
> +            if (read_dialogue(ass, &rline, line.str, &ts_start, &duration) < 0)
>                  continue;
> -            sub = ff_subtitles_queue_insert(&ass->q, line.str, line.len, 0);
> +            sub = ff_subtitles_queue_insert(&ass->q, rline.str, rline.len, 0);
>              if (!sub) {
>                  res = AVERROR(ENOMEM);
>                  goto end;
> @@ -139,6 +149,7 @@ static int ass_read_header(AVFormatContext *s)
>      }
>  
>      av_bprint_finalize(&line, NULL);
> +    av_bprint_finalize(&rline, NULL);
>  
>      res = avpriv_bprint_to_extradata(st->codec, &header);
>      if (res < 0)

Otherwise LGTM.