On 2021-06-18 01:53, Timo Rothenpieler wrote:
---
doc/filters.texi | 6 ++++++
libavfilter/f_select.c | 18 ++++++++++++++++++
libavfilter/version.h | 2 +-
3 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index da8f7d7726..db6ecd7c2a 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -5404,6 +5404,7 @@ Set sidechain gain. Default is 1. Range is from 0.015625
to 64.
This filter supports the all above options as @ref{commands}.
+@anchor{silencedetect}
@section silencedetect
Detect silence in an audio stream.
@@ -25564,6 +25565,11 @@ missing.
That basically means that an input frame is selected if its pts is within the
interval set by the concat demuxer.
+@item silence_detected
+Evaluates the metadata added to frames by the @ref{silencedetect} filter.
+The @var{silence_detected} variable is -1 if silence was detected for the
current
+frame, 0 otherwise.
+
Instead of a specific option for silencedetect, it would be future-proof
if it was an option called, say, metadata with a constant for
silencedetect to start with.
There are multiple per-frame analysis filters like blackframe,
blackdetect, freezedetect..etc and it will be easier to just extend
'metadata' with new constants
than to add a new option for each filter.
@end table
The default value of the select expression is "1".
diff --git a/libavfilter/f_select.c b/libavfilter/f_select.c
index f0468078e8..1e655290f4 100644
--- a/libavfilter/f_select.c
+++ b/libavfilter/f_select.c
@@ -86,6 +86,8 @@ static const char *const var_names[] = {
"concatdec_select", ///< frame is within the interval set by the concat demuxer
+ "silence_detected", ///< silencedetect detected silence for this frame
+
NULL
};
@@ -138,6 +140,8 @@ enum var_name {
VAR_CONCATDEC_SELECT,
+ VAR_SILENCE_DETECTED,
+
VAR_VARS_NB
};
@@ -157,6 +161,7 @@ typedef struct SelectContext {
double select;
int select_out; ///< mark the selected output pad index
int nb_outputs;
+ int silence_detected;
} SelectContext;
#define OFFSET(x) offsetof(SelectContext, x)
@@ -325,6 +330,18 @@ static double get_concatdec_select(AVFrame *frame, int64_t
pts)
return NAN;
}
+static double get_silence_detected(SelectContext *select, AVFrame *frame)
+{
+ AVDictionary *metadata = frame->metadata;
+ AVDictionaryEntry *start = av_dict_get(metadata, "lavfi.silence_start",
NULL, 0);
+ AVDictionaryEntry *end = av_dict_get(metadata, "lavfi.silence_end", NULL,
0);
+ if (start)
+ select->silence_detected = -1;
+ if (end)
+ select->silence_detected = 0;
+ return select->silence_detected;
+}
+
static void select_frame(AVFilterContext *ctx, AVFrame *frame)
{
SelectContext *select = ctx->priv;
@@ -342,6 +359,7 @@ static void select_frame(AVFilterContext *ctx, AVFrame
*frame)
select->var_values[VAR_POS] = frame->pkt_pos == -1 ? NAN : frame->pkt_pos;
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));
+ select->var_values[VAR_SILENCE_DETECTED] = get_silence_detected(select,
frame);
switch (inlink->type) {
case AVMEDIA_TYPE_AUDIO:
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 5052681653..fbb81ef31c 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,7 +31,7 @@
#define LIBAVFILTER_VERSION_MAJOR 8
#define LIBAVFILTER_VERSION_MINOR 0
-#define LIBAVFILTER_VERSION_MICRO 102
+#define LIBAVFILTER_VERSION_MICRO 103
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
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