[FFmpeg-devel] [PATCH 1/4] avfilter/vf_drawtext: add option to draw timecode in S12M side data

[Nicolas George]

lance.lmwang at gmail.com (12020-06-19):
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>  doc/filters.texi          |  4 ++++
>  libavfilter/vf_drawtext.c | 19 +++++++++++++++++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 5f0eb28..8334f46 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -9825,6 +9825,10 @@ If both @var{text} and @var{textfile} are specified, an error is thrown.
>  If set to 1, the @var{textfile} will be reloaded before each frame.
>  Be sure to update it atomically, or it may be read partially, or even fail.
>  

> + at item frame_tc
> +If set to 1, the timecode in S12M side data will be used for each frame
> +if have, 0 otherwise

I think it should be part of the text expansion mechanism, not a
separate option.

> +
>  @item x
>  @item y
>  The expressions which specify the offsets where text will be drawn
> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> index abe1ca6..018997a 100644
> --- a/libavfilter/vf_drawtext.c
> +++ b/libavfilter/vf_drawtext.c
> @@ -197,6 +197,7 @@ typedef struct DrawTextContext {
>      AVRational  tc_rate;            ///< frame rate for timecode
>      AVTimecode  tc;                 ///< timecode context
>      int tc24hmax;                   ///< 1 if timecode is wrapped to 24 hours, 0 otherwise
> +    int frame_tc;                   ///< 1 use timecode in S12M side data for each frame, 0 otherwise
>      int reload;                     ///< reload text file for each frame
>      int start_number;               ///< starting frame number for n/frame_num var
>  #if CONFIG_LIBFRIBIDI
> @@ -268,6 +269,7 @@ static const AVOption drawtext_options[]= {
>          { "monochrome",                  NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FT_LOAD_MONOCHROME },                  .flags = FLAGS, .unit = "ft_load_flags" },
>          { "linear_design",               NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FT_LOAD_LINEAR_DESIGN },               .flags = FLAGS, .unit = "ft_load_flags" },
>          { "no_autohint",                 NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FT_LOAD_NO_AUTOHINT },                 .flags = FLAGS, .unit = "ft_load_flags" },
> +    {"frame_tc",   "use timecode in S21M side data for each frame if have", OFFSET(frame_tc),   AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS},
>      { NULL }
>  };
>  
> @@ -1327,6 +1329,23 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame,
>          break;
>      }
>  
> +    if (s->frame_tc) {
> +        AVFrameSideData *sd;
> +
> +        if (sd = av_frame_get_side_data(frame, AV_FRAME_DATA_S12M_TIMECODE)) {
> +            uint32_t *tc = (uint32_t*)sd->data;
> +            int m  = tc[0] & 3;
> +
> +            av_bprint_clear(bp);
> +            av_bprintf(bp, "%s", s->text);
> +            for (int j = 1; j <= m; j++) {
> +                char tcbuf[AV_TIMECODE_STR_SIZE];
> +                av_timecode_make_smpte_tc_string(tcbuf, tc[j], 0);
> +                av_bprintf(bp, "%s%s", tcbuf, j != m ? ", " : "");
> +            }
> +        }
> +    }
> +
>      if (s->tc_opt_string) {
>          char tcbuf[AV_TIMECODE_STR_SIZE];
>          av_timecode_make_string(&s->tc, tcbuf, inlink->frame_count_out);

Regards,

-- 
  Nicolas George
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