diff --git a/doc/filters.texi b/doc/filters.texi index f351390e28..25134fd886 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -13196,6 +13196,25 @@ value between 0 and 1 to indicate a new scene; a low value reflects a low probability for the current frame to introduce a new scene, while a higher value means the current frame is more likely to be one (see the example below) +@item concatdec_select +The concat demuxer can select only part of a concat input file by setting an +inpoint and an outpoint, but the output packets may not be entirely contained +in the selected interval. By using this variable, it is possible to skip frames +generated by the concat demuxer which are not exactly contained in the selected +interval. + +This works by comparing the frame pts against the @var{lavf.concat.start_time} +and the @var{lavf.concat.duration} packet metadata values which are also +present in the decoded frames. + +The @var{concatdec_select} variable is -1 if the frame pts is at least +start_time and either the duration metadata is missing or the frame pts is less +than start_time + duration, 0 otherwise, and NaN if the start_time metadata is +missing. + +That basically means that an input frame is selected if its pts is within the +interval set by the concat demuxer. + @end table The default value of the select expression is "1". @@ -13270,6 +13289,13 @@ Send even and odd frames to separate outputs, and compose them: @example select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h @end example + +@item +Select useful frames from an ffconcat file which is using inpoints and +outpoints but where the source files are not intra frame only. +@example +ffmpeg -copyts -vsync 0 -segment_time_metadata 1 -i input.ffconcat -vf select=concatdec_select -af aselect=concatdec_select output.avi +@end example @end itemize @section selectivecolor diff --git a/libavfilter/f_select.c b/libavfilter/f_select.c index 2b926e1e14..52f474eb93 100644 --- a/libavfilter/f_select.c +++ b/libavfilter/f_select.c @@ -82,6 +82,8 @@ static const char *const var_names[] = { "scene", + "concatdec_select", ///< frame is within the interval set by the concat demuxer + NULL }; @@ -132,6 +134,8 @@ enum var_name { VAR_SCENE, + VAR_CONCATDEC_SELECT, + VAR_VARS_NB }; @@ -278,6 +282,28 @@ static double get_scene_score(AVFilterContext *ctx, AVFrame *frame) return ret; } +static double get_concatdec_select(AVFrame *frame, int64_t pts) +{ + AVDictionary *metadata = av_frame_get_metadata(frame); + AVDictionaryEntry *start_time_entry = av_dict_get(metadata, "lavf.concatdec.start_time", NULL, 0); + AVDictionaryEntry *duration_entry = av_dict_get(metadata, "lavf.concatdec.duration", NULL, 0); + if (start_time_entry) { + int64_t start_time = strtoll(start_time_entry->value, NULL, 10); + if (pts >= start_time) { + if (duration_entry) { + int64_t duration = strtoll(duration_entry->value, NULL, 10); + if (pts < start_time + duration) + return -1; + else + return 0; + } + return -1; + } + return 0; + } + return NAN; +} + #define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d)) #define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts)) @@ -297,6 +323,7 @@ static void select_frame(AVFilterContext *ctx, AVFrame *frame) select->var_values[VAR_T ] = TS2D(frame->pts) * av_q2d(inlink->time_base); select->var_values[VAR_POS] = av_frame_get_pkt_pos(frame) == -1 ? NAN : av_frame_get_pkt_pos(frame); select->var_values[VAR_KEY] = frame->key_frame; + select->var_values[VAR_CONCATDEC_SELECT] = get_concatdec_select(frame, av_rescale_q(frame->pts, inlink->time_base, AV_TIME_BASE_Q)); switch (inlink->type) { case AVMEDIA_TYPE_AUDIO: