This option can be used to select useful frames from an ffconcat file which is
using inpoints and outpoints but where the source files are not intra frame
only.
Signed-off-by: Marton Balint <c...@passwd.hu>
---
doc/filters.texi | 17 +++++++++++++++++
libavfilter/f_select.c | 20 ++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/doc/filters.texi b/doc/filters.texi
index 5a35bde..093eec5 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -13160,6 +13160,16 @@ 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 sets the @var{lavf.concat.start_time} and the
+@var{lavf.concat.duration} packet metadata values which are also present in the
+decoded frames. These metadata entries contain the start_time and the duration
+of the respective file segments in the concatenated output.
+
+The @var{concatdec_select} variable is -1 if the frame pts is at least
+start_time but less than start_time + duration, 0 otherwise, and NaN if the
+mentioned metadata entires are not present.
+
@end table
The default value of the select expression is "1".
@@ -13234,6 +13244,13 @@ 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 -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 2b926e1..d5f1470 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 usefulness based on pts and frame metadata
originating from the concat demuxer
+
NULL
};
@@ -132,6 +134,8 @@ enum var_name {
VAR_SCENE,
+ VAR_CONCATDEC_SELECT,
+
VAR_VARS_NB
};
@@ -278,6 +282,21 @@ 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 *e1 = av_dict_get(metadata, "lavf.concatdec.start_time",
NULL, 0);
+ AVDictionaryEntry *e2 = av_dict_get(metadata, "lavf.concatdec.duration",
NULL, 0);
+ if (e1 && e1->value && e2 && e2->value) {
+ int64_t start_time = strtoll(e1->value, NULL, 10);
+ int64_t duration = strtoll(e2->value, NULL, 10);
+ if (pts >= start_time && pts < start_time + duration)
+ 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 +316,7 @@ 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:
--
2.1.4
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