[FFmpeg-devel] [PATCH] avfilter/drawtext: make reload value an interval

[Gyan Doshi]

Plan to push tomorrow.

On 2022-02-28 12:58 pm, Gyan Doshi wrote:
> Allows user to specify a frame interval at which textfile is reloaded.
> ---
>   doc/filters.texi          | 6 ++++--
>   libavfilter/vf_drawtext.c | 6 +++---
>   2 files changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/doc/filters.texi b/doc/filters.texi
> index b3ae139613..1ecc03eeae 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -11271,8 +11271,10 @@ text data in detection bboxes of side data. So please do not use this parameter
>   if you are not sure about the text source.
>   
>   @item reload
> -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.
> +The @var{textfile} will be reloaded at specified frame interval.
> +Be sure to update @var{textfile} atomically, or it may be read partially,
> +or even fail.
> +Range is 0 to INT_MAX. Default is 0.
>   
>   @item x
>   @item y
> diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c
> index 2a88692cbd..6ba3f6622a 100644
> --- a/libavfilter/vf_drawtext.c
> +++ b/libavfilter/vf_drawtext.c
> @@ -198,7 +198,7 @@ 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 reload;                     ///< reload text file for each frame
> +    int reload;                     ///< reload text file at specified frame interval
>       int start_number;               ///< starting frame number for n/frame_num var
>       char *text_source_string;       ///< the string to specify text data source
>       enum AVFrameSideDataType text_source;
> @@ -245,7 +245,7 @@ static const AVOption drawtext_options[]= {
>       {"timecode_rate",   "set rate (timecode only)",         OFFSET(tc_rate),       AV_OPT_TYPE_RATIONAL, {.dbl=0},           0,  INT_MAX, FLAGS},
>       {"r",               "set rate (timecode only)",         OFFSET(tc_rate),       AV_OPT_TYPE_RATIONAL, {.dbl=0},           0,  INT_MAX, FLAGS},
>       {"rate",            "set rate (timecode only)",         OFFSET(tc_rate),       AV_OPT_TYPE_RATIONAL, {.dbl=0},           0,  INT_MAX, FLAGS},
> -    {"reload",     "reload text file for each frame",                       OFFSET(reload),     AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS},
> +    {"reload",     "reload text file at specified frame interval", OFFSET(reload),     AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS},
>       { "alpha",       "apply alpha while rendering", OFFSET(a_expr),      AV_OPT_TYPE_STRING, { .str = "1"     },          .flags = FLAGS },
>       {"fix_bounds", "check and fix text coords to avoid clipping", OFFSET(fix_bounds), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS},
>       {"start_number", "start frame number for n/frame_num variable", OFFSET(start_number), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS},
> @@ -1565,7 +1565,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
>           }
>       }
>   
> -    if (s->reload) {
> +    if (s->reload && !(inlink->frame_count_out % s->reload)) {
>           if ((ret = load_textfile(ctx)) < 0) {
>               av_frame_free(&frame);
>               return ret;