[FFmpeg-devel] [PATCH] avcodec/ccaption_dec: don't print multiple \pos tags per cue

[Stefano Sabatini]

On date Sunday 2024-03-10 19:40:47 -0500, Marth64 wrote:
> Currently, Closed Captions decoder prints multiple \pos ASS tags per line,
> per cue. This is invalid behavior, because only the first \pos tag in a cue
> is honored by ASS anyway. Don't write multiple \pos tags.
> 
> Signed-off-by: Marth64 <marth64 at proxyid.net>
> ---
>  libavcodec/ccaption_dec.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/ccaption_dec.c b/libavcodec/ccaption_dec.c
> index faf058ce97..9d4a93647c 100644
> --- a/libavcodec/ccaption_dec.c
> +++ b/libavcodec/ccaption_dec.c
> @@ -456,7 +456,7 @@ static void roll_up(CCaptionSubContext *ctx)
>  
>  static int capture_screen(CCaptionSubContext *ctx)
>  {
> -    int i, j, tab = 0;
> +    int i, j, tab = 0, seen_row = 0;
>      struct Screen *screen = ctx->screen + ctx->active_screen;
>      enum cc_font prev_font = CCFONT_REGULAR;
>      enum cc_color_code prev_color = CCCOL_WHITE;
> @@ -496,7 +496,11 @@ static int capture_screen(CCaptionSubContext *ctx)
>  
>              x = ASS_DEFAULT_PLAYRESX * (0.1 + 0.0250 * j);
>              y = ASS_DEFAULT_PLAYRESY * (0.1 + 0.0533 * i);
> -            av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
> +
> +            if (!seen_row) {
> +                av_bprintf(&ctx->buffer[bidx], "{\\an7}{\\pos(%d,%d)}", x, y);
> +                seen_row = 1;
> +            }
>  
>              for (; j < SCREEN_COLUMNS; j++) {
>                  const char *e_tag = "", *s_tag = "", *c_tag = "", *b_tag = "";

LGTM, thanks.