[FFmpeg-devel] [PATCH v3 1/2] ffmpeg: refactor post-decoding steps for subtitles into a function

[Anton Khirnov]

Quoting Jan Ekström (2022-07-29 15:35:36)
> From: Jan Ekström <jan.ekstrom at 24i.com>
> 
> This enables us to later call this when generating additional
> subtitles for splitting purposes.
> 
> Co-authored-by: Andrzej Nadachowski <andrzej.nadachowski at 24i.com>
> 
> Signed-off-by: Jan Ekström <jan.ekstrom at 24i.com>
> ---
>  fftools/ffmpeg.c | 50 ++++++++++++++++++++++++++++--------------------
>  1 file changed, 29 insertions(+), 21 deletions(-)
> 
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 4746742c02..adcab43a30 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -2301,27 +2301,16 @@ fail:
>      return err < 0 ? err : ret;
>  }
>  
> -static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output,
> -                               int *decode_failed)
> +static int encode_mux_subtitles(InputStream *ist, AVSubtitle *subtitle, int *got_output)
>  {
> -    AVSubtitle subtitle;
> +    int ret = 0;
>      int free_sub = 1;
> -    int i, ret = avcodec_decode_subtitle2(ist->dec_ctx,
> -                                          &subtitle, got_output, pkt);
>  
> -    check_decode_result(NULL, got_output, ret);
> -
> -    if (ret < 0 || !*got_output) {
> -        *decode_failed = 1;
> -        if (!pkt->size)
> -            sub2video_flush(ist);
> -        return ret;
> -    }
>  
>      if (ist->fix_sub_duration) {
>          int end = 1;
>          if (ist->prev_sub.got_output) {
> -            end = av_rescale(subtitle.pts - ist->prev_sub.subtitle.pts,
> +            end = av_rescale(subtitle->pts - ist->prev_sub.subtitle.pts,
>                               1000, AV_TIME_BASE);
>              if (end < ist->prev_sub.subtitle.end_display_time) {
>                  av_log(NULL, AV_LOG_DEBUG,
> @@ -2333,7 +2322,7 @@ static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output,
>          }
>          FFSWAP(int,        *got_output, ist->prev_sub.got_output);
>          FFSWAP(int,        ret,         ist->prev_sub.ret);
> -        FFSWAP(AVSubtitle, subtitle,    ist->prev_sub.subtitle);
> +        FFSWAP(AVSubtitle, *subtitle,   ist->prev_sub.subtitle);
>          if (end <= 0)
>              goto out;
>      }
> @@ -2342,40 +2331,59 @@ static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output,
>          return ret;
>  
>      if (ist->sub2video.frame) {
> -        sub2video_update(ist, INT64_MIN, &subtitle);
> +        sub2video_update(ist, INT64_MIN, subtitle);
>      } else if (ist->nb_filters) {
>          if (!ist->sub2video.sub_queue)
>              ist->sub2video.sub_queue = av_fifo_alloc2(8, sizeof(AVSubtitle), AV_FIFO_FLAG_AUTO_GROW);
>          if (!ist->sub2video.sub_queue)
>              exit_program(1);
>  
> -        ret = av_fifo_write(ist->sub2video.sub_queue, &subtitle, 1);
> +        ret = av_fifo_write(ist->sub2video.sub_queue, subtitle, 1);
>          if (ret < 0)
>              exit_program(1);
>          free_sub = 0;
>      }
>  
> -    if (!subtitle.num_rects)
> +    if (!subtitle->num_rects)
>          goto out;
>  
>      ist->frames_decoded++;
>  
> -    for (i = 0; i < nb_output_streams; i++) {
> +    for (int i = 0; i < nb_output_streams; i++) {
>          OutputStream *ost = output_streams[i];
>  
>          if (!check_output_constraints(ist, ost) || !ost->encoding_needed
>              || ost->enc->type != AVMEDIA_TYPE_SUBTITLE)
>              continue;
>  
> -        do_subtitle_out(output_files[ost->file_index], ost, &subtitle);
> +        do_subtitle_out(output_files[ost->file_index], ost, subtitle);
>      }
>  
>  out:
>      if (free_sub)
> -        avsubtitle_free(&subtitle);
> +        avsubtitle_free(subtitle);
>      return ret;
>  }
>  
> +static int transcode_subtitles(InputStream *ist, AVPacket *pkt, int *got_output,
> +                               int *decode_failed)
> +{
> +    AVSubtitle subtitle;
> +    int ret = avcodec_decode_subtitle2(ist->dec_ctx,
> +                                       &subtitle, got_output, pkt);
> +
> +    check_decode_result(NULL, got_output, ret);
> +
> +    if (ret < 0 || !*got_output) {
> +        *decode_failed = 1;
> +        if (!pkt->size)
> +            sub2video_flush(ist);
> +        return ret;
> +    }
> +
> +    return encode_mux_subtitles(ist, &subtitle, got_output);
> +}
> +
>  static int send_filter_eof(InputStream *ist)
>  {
>      int i, ret;
> -- 
> 2.37.1
> 
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-- 
Anton Khirnov