diff options
| -rw-r--r-- | doc/filters.texi | 4 | ||||
| -rw-r--r-- | libavfilter/vf_drawtext.c | 4 |
2 files changed, 7 insertions, 1 deletions
diff --git a/doc/filters.texi b/doc/filters.texi index 6e616b26b4..694e5a1682 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -3068,6 +3068,10 @@ The x and y offsets for the text shadow position with respect to the position of the text. They can be either positive or negative values. Default value for both is "0". +@item start_number +The starting frame number for the n/frame_num variable. The default value +is "0". + @item tabsize The size in number of spaces to use for rendering the tab. Default value is 4. diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c index 157bfc72f9..7cafafefc7 100644 --- a/libavfilter/vf_drawtext.c +++ b/libavfilter/vf_drawtext.c @@ -164,6 +164,7 @@ typedef struct { 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 start_number; ///< starting frame number for n/frame_num var } DrawTextContext; #define OFFSET(x) offsetof(DrawTextContext, x) @@ -198,6 +199,7 @@ static const AVOption drawtext_options[]= { {"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_INT, {.i64=0}, 0, 1, FLAGS}, {"fix_bounds", "if true, check and fix text coords to avoid clipping", OFFSET(fix_bounds), AV_OPT_TYPE_INT, {.i64=1}, 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}, /* FT_LOAD_* flags */ { "ft_load_flags", "set font loading flags for libfreetype", OFFSET(ft_load_flags), AV_OPT_TYPE_FLAGS, { .i64 = FT_LOAD_DEFAULT | FT_LOAD_RENDER}, 0, INT_MAX, FLAGS, "ft_load_flags" }, @@ -978,7 +980,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame) if ((ret = load_textfile(ctx)) < 0) return ret; - s->var_values[VAR_N] = inlink->frame_count; + s->var_values[VAR_N] = inlink->frame_count+s->start_number; s->var_values[VAR_T] = frame->pts == AV_NOPTS_VALUE ? NAN : frame->pts * av_q2d(inlink->time_base); |