[FFmpeg-cvslog] lavfi: add audio silencedetect filter.
Clément Bœsch
git at videolan.org
Sun Jan 8 17:10:36 CET 2012
ffmpeg | branch: master | Clément Bœsch <ubitux at gmail.com> | Tue Jan 3 23:47:09 2012 +0100| [0c01947316eaaa46946f9e93218fe5ab115df905] | committer: Clément Bœsch
lavfi: add audio silencedetect filter.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0c01947316eaaa46946f9e93218fe5ab115df905
---
Changelog | 1 +
doc/filters.texi | 30 +++++++
libavfilter/Makefile | 1 +
libavfilter/af_silencedetect.c | 175 ++++++++++++++++++++++++++++++++++++++++
libavfilter/allfilters.c | 1 +
libavfilter/avfilter.h | 4 +-
6 files changed, 210 insertions(+), 2 deletions(-)
diff --git a/Changelog b/Changelog
index 13736b0..a32a4eb 100644
--- a/Changelog
+++ b/Changelog
@@ -20,6 +20,7 @@ version next:
- v308 Quicktime Uncompressed 4:4:4 encoder and decoder
- yuv4 libquicktime packed 4:2:0 encoder and decoder
- ffprobe -show_frames option
+- silencedetect audio filter
version 0.9:
diff --git a/doc/filters.texi b/doc/filters.texi
index eaa2c33..d0075f2 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -358,6 +358,36 @@ Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
that should be preferred (see "-ac" option) unless you have very specific
needs.
+ at section silencedetect
+
+Detect silence in an audio stream.
+
+This filter logs a message when it detects that the input audio volume is less
+or equal to a noise tolerance value for a duration greater or equal to the
+minimum detected noise duration.
+
+The printed times and duration are expressed in seconds.
+
+ at table @option
+ at item duration, d
+Set silence duration until notification (default is 2 seconds).
+
+ at item noise, n
+Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
+specified value) or amplitude ratio. Default is -60dB, or 0.001.
+ at end table
+
+Detect 5 seconds of silence with -50dB noise tolerance:
+ at example
+silencedetect=n=-50dB:d=5
+ at end example
+
+Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
+tolerance in @file{silence.mp3}:
+ at example
+ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
+ at end example
+
@section volume
Adjust the input audio volume.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 0d8f120..d4b71d2 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -34,6 +34,7 @@ OBJS-$(CONFIG_ASPLIT_FILTER) += af_asplit.o
OBJS-$(CONFIG_ASTREAMSYNC_FILTER) += af_astreamsync.o
OBJS-$(CONFIG_EARWAX_FILTER) += af_earwax.o
OBJS-$(CONFIG_PAN_FILTER) += af_pan.o
+OBJS-$(CONFIG_SILENCEDETECT_FILTER) += af_silencedetect.o
OBJS-$(CONFIG_VOLUME_FILTER) += af_volume.o
OBJS-$(CONFIG_ABUFFER_FILTER) += asrc_abuffer.o
diff --git a/libavfilter/af_silencedetect.c b/libavfilter/af_silencedetect.c
new file mode 100644
index 0000000..73521b0
--- /dev/null
+++ b/libavfilter/af_silencedetect.c
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2012 Clément Bœsch <ubitux at gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Audio silence detector
+ */
+
+#include "libavutil/opt.h"
+#include "avfilter.h"
+
+typedef struct {
+ const AVClass *class;
+ char *noise_str; ///< noise option string
+ double noise; ///< noise amplitude ratio
+ int duration; ///< minimum duration of silence until notification
+ int64_t nb_null_samples; ///< current number of continuous zero samples
+ double start; ///< if silence is detected, this value contains the time of the first zero sample
+ int last_sample_rate; ///< last sample rate to check for sample rate changes
+} SilenceDetectContext;
+
+#define OFFSET(x) offsetof(SilenceDetectContext, x)
+static const AVOption silencedetect_options[] = {
+ { "n", "set noise tolerance", OFFSET(noise_str), AV_OPT_TYPE_STRING, {.str="-60dB"}, CHAR_MIN, CHAR_MAX },
+ { "noise", "set noise tolerance", OFFSET(noise_str), AV_OPT_TYPE_STRING, {.str="-60dB"}, CHAR_MIN, CHAR_MAX },
+ { "d", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_INT, {.dbl=2}, 0, INT_MAX},
+ { "duration", "set minimum duration in seconds", OFFSET(duration), AV_OPT_TYPE_INT, {.dbl=2}, 0, INT_MAX},
+ { NULL },
+};
+
+static const char *silencedetect_get_name(void *ctx)
+{
+ return "silencedetect";
+}
+
+static const AVClass silencedetect_class = {
+ .class_name = "SilenceDetectContext",
+ .item_name = silencedetect_get_name,
+ .option = silencedetect_options,
+};
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+ int ret;
+ char *tail;
+ SilenceDetectContext *silence = ctx->priv;
+
+ silence->class = &silencedetect_class;
+ av_opt_set_defaults(silence);
+
+ if ((ret = av_set_options_string(silence, args, "=", ":")) < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error parsing options string: '%s'\n", args);
+ return ret;
+ }
+
+ silence->noise = strtod(silence->noise_str, &tail);
+ if (!strcmp(tail, "dB")) {
+ silence->noise = pow(10, silence->noise/20);
+ } else if (*tail) {
+ av_log(ctx, AV_LOG_ERROR, "Invalid value '%s' for noise parameter.\n",
+ silence->noise_str);
+ return AVERROR(EINVAL);
+ }
+
+ return 0;
+}
+
+static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples)
+{
+ int i;
+ SilenceDetectContext *silence = inlink->dst->priv;
+ const int nb_channels = av_get_channel_layout_nb_channels(inlink->channel_layout);
+ const int srate = inlink->sample_rate;
+ const int nb_samples = insamples->audio->nb_samples * nb_channels;
+ const int64_t nb_samples_notify = srate * silence->duration * nb_channels;
+
+ // scale number of null samples to the new sample rate
+ if (silence->last_sample_rate && silence->last_sample_rate != srate)
+ silence->nb_null_samples =
+ srate * silence->nb_null_samples / silence->last_sample_rate;
+ silence->last_sample_rate = srate;
+
+ // TODO: support more sample formats
+ if (insamples->format == AV_SAMPLE_FMT_DBL) {
+ double *p = (double *)insamples->data[0];
+
+ for (i = 0; i < nb_samples; i++, p++) {
+ if (*p < silence->noise && *p > -silence->noise) {
+ if (!silence->start) {
+ silence->nb_null_samples++;
+ if (silence->nb_null_samples >= nb_samples_notify) {
+ silence->start = insamples->pts * av_q2d(inlink->time_base) - silence->duration;
+ av_log(silence, AV_LOG_INFO,
+ "silence_start: %f\n", silence->start);
+ }
+ }
+ } else {
+ if (silence->start) {
+ double end = insamples->pts * av_q2d(inlink->time_base);
+ av_log(silence, AV_LOG_INFO,
+ "silence_end: %f | silence_duration: %f\n",
+ end, end - silence->start);
+ }
+ silence->nb_null_samples = silence->start = 0;
+ }
+ }
+ }
+
+ avfilter_filter_samples(inlink->dst->outputs[0], insamples);
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+ AVFilterFormats *formats = NULL;
+ enum AVSampleFormat sample_fmts[] = {
+ AV_SAMPLE_FMT_DBL,
+ AV_SAMPLE_FMT_NONE
+ };
+ int packing_fmts[] = { AVFILTER_PACKED, -1 };
+
+ formats = avfilter_make_all_channel_layouts();
+ if (!formats)
+ return AVERROR(ENOMEM);
+ avfilter_set_common_channel_layouts(ctx, formats);
+
+ formats = avfilter_make_format_list(sample_fmts);
+ if (!formats)
+ return AVERROR(ENOMEM);
+ avfilter_set_common_sample_formats(ctx, formats);
+
+ formats = avfilter_make_format_list(packing_fmts);
+ if (!formats)
+ return AVERROR(ENOMEM);
+ avfilter_set_common_packing_formats(ctx, formats);
+
+ return 0;
+}
+
+AVFilter avfilter_af_silencedetect = {
+ .name = "silencedetect",
+ .description = NULL_IF_CONFIG_SMALL("Detect silence."),
+ .priv_size = sizeof(SilenceDetectContext),
+ .init = init,
+ .query_formats = query_formats,
+
+ .inputs = (const AVFilterPad[]) {
+ { .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .get_audio_buffer = avfilter_null_get_audio_buffer,
+ .filter_samples = filter_samples, },
+ { .name = NULL }
+ },
+ .outputs = (const AVFilterPad[]) {
+ { .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO, },
+ { .name = NULL }
+ },
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 621568e..8286d4d 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -44,6 +44,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (ASTREAMSYNC, astreamsync, af);
REGISTER_FILTER (EARWAX, earwax, af);
REGISTER_FILTER (PAN, pan, af);
+ REGISTER_FILTER (SILENCEDETECT, silencedetect, af);
REGISTER_FILTER (VOLUME, volume, af);
REGISTER_FILTER (ABUFFER, abuffer, asrc);
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index d88d3ab..9c79597 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -30,8 +30,8 @@
#include "libavcodec/avcodec.h"
#define LIBAVFILTER_VERSION_MAJOR 2
-#define LIBAVFILTER_VERSION_MINOR 57
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR 58
+#define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \
More information about the ffmpeg-cvslog
mailing list