[FFmpeg-devel] [PATCH 03/10] libavcodec/ccaption_dec: add calculate_duration option

[Anshul Maheshwari]

On Thu, Jan 7, 2016 at 6:10 AM, Aman Gupta <ffmpeg at tmm1.net> wrote:

> > Aman Gupta <ffmpeg at tmm1.net> wrote:
> > > --- a/libavcodec/ccaption_dec.c
> > > +++ b/libavcodec/ccaption_dec.c
> > > @@ -150,6 +150,7 @@ struct Screen {
> > >
> > >  typedef struct CCaptionSubContext {
> > >      AVClass *class;
> > > +    int calculate_duration;
> > >      struct Screen screen[2];
> > >      int active_screen;
> > >      uint8_t cursor_row;
> > > @@ -545,8 +546,12 @@ static int decode(AVCodecContext *avctx, void
> > *data, int *got_sub, AVPacket *avp
> > >              continue;
> > >          else
> > >              process_cc608(ctx, *(bptr + i + 1) & 0x7f, *(bptr + i + 2)
> > & 0x7f);
> > > -        if (ctx->screen_changed)
> > > -        {
> > > +
> > > +        if (!ctx->screen_changed)
> > > +            continue;
> > > +        ctx->screen_changed = 0;
> > > +
> > > +        if (ctx->calculate_duration) {
> > >              if (ctx->prev_string) {
> > >                  int start_time = av_rescale_q(ctx->prev_time,
> > avctx->time_base, (AVRational){ 1, 100 });
> > >                  int end_time = av_rescale_q(avpkt->pts,
> > avctx->time_base, (AVRational){ 1, 100 });
> > > @@ -560,7 +565,12 @@ static int decode(AVCodecContext *avctx, void
> > *data, int *got_sub, AVPacket *avp
> > >              av_bprintf(&ctx->buffer, "\r\n");
> > >              ctx->prev_string = av_strdup(ctx->buffer.str);
> > >              ctx->prev_time = avpkt->pts;
> > > -            ctx->screen_changed = 0;
> > > +        } else {
> > > +            int start_time = av_rescale_q(avpkt->pts,
> avctx->time_base,
> > (AVRational){ 1, 100 });
> > > +            ret = ff_ass_add_rect_bprint(sub, &ctx->buffer,
> start_time,
> > -1);
>
Is it possible to check the length of buffer, and avoid empty frames.

> > > +            if (ret < 0)
> > > +                return ret;
> > > +            sub->pts = av_rescale_q(avpkt->pts, avctx->time_base,
> > AV_TIME_BASE_Q);
> > >          }
> > >      }
> > >
> > > @@ -568,7 +578,10 @@ static int decode(AVCodecContext *avctx, void
> > *data, int *got_sub, AVPacket *avp
> > >      return ret;
> > >  }
> > >
> > > +#define OFFSET(x) offsetof(CCaptionSubContext, x)
> > > +#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
> > >  static const AVOption options[] = {
> > > +    { "calculate_duration", "Buffer closed captions to calculate
> > durations.", OFFSET(calculate_duration), AV_OPT_TYPE_BOOL, { .i64 = 1 },
> 0,
> > 1, SD },
> > >      {NULL}
> > >  };
> > >
> >
>