[FFmpeg-cvslog] avfilter: add stereowiden filter
Paul B Mahol
git at videolan.org
Tue Sep 15 12:09:10 CEST 2015
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Sat Sep 12 04:01:18 2015 +0000| [b0f985661678323e03815f4bd88b1391e9dd7a18] | committer: Paul B Mahol
avfilter: add stereowiden filter
Signed-off-by: Paul B Mahol <onemda at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b0f985661678323e03815f4bd88b1391e9dd7a18
---
Changelog | 1 +
doc/filters.texi | 27 +++++++
libavfilter/Makefile | 1 +
libavfilter/af_stereowiden.c | 167 ++++++++++++++++++++++++++++++++++++++++++
libavfilter/allfilters.c | 1 +
libavfilter/version.h | 2 +-
6 files changed, 198 insertions(+), 1 deletion(-)
diff --git a/Changelog b/Changelog
index 77607e5..653317f 100644
--- a/Changelog
+++ b/Changelog
@@ -6,6 +6,7 @@ version <next>:
- extrastereo filter
- ocr filter
- alimiter filter
+- stereowiden filter
version 2.8:
diff --git a/doc/filters.texi b/doc/filters.texi
index 4958374..9b6e6ff 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2394,6 +2394,33 @@ silenceremove=1:5:0.02
@end example
@end itemize
+ at section stereowiden
+
+This filter enhance the stereo effect by suppressing signal common to both
+channels and by delaying the signal of left into right and vice versa,
+thereby widening the stereo effect.
+
+The filter accepts the following options:
+
+ at table @option
+ at item delay
+Time in milliseconds of the delay of left signal into right and vice versa.
+Default is 20 milliseconds.
+
+ at item feedback
+Amount of gain in delayed signal into right and vice versa. Gives a delay
+effect of left signal in right output and vice versa which gives widening
+effect. Default is 0.3.
+
+ at item crossfeed
+Cross feed of left into right with inverted phase. This helps in suppressing
+the mono. If the value is 1 it will cancel all the signal common to both
+channels. Default is 0.3.
+
+ at item drymix
+Set level of input signal of original channel. Default is 0.8.
+ at end table
+
@section treble
Boost or cut treble (upper) frequencies of the audio using a two-pole
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index b0a2a7a..03e18d2 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -80,6 +80,7 @@ OBJS-$(CONFIG_RESAMPLE_FILTER) += af_resample.o
OBJS-$(CONFIG_SIDECHAINCOMPRESS_FILTER) += af_sidechaincompress.o
OBJS-$(CONFIG_SILENCEDETECT_FILTER) += af_silencedetect.o
OBJS-$(CONFIG_SILENCEREMOVE_FILTER) += af_silenceremove.o
+OBJS-$(CONFIG_STEREOWIDEN_FILTER) += af_stereowiden.o
OBJS-$(CONFIG_TREBLE_FILTER) += af_biquads.o
OBJS-$(CONFIG_VOLUME_FILTER) += af_volume.o
OBJS-$(CONFIG_VOLUMEDETECT_FILTER) += af_volumedetect.o
diff --git a/libavfilter/af_stereowiden.c b/libavfilter/af_stereowiden.c
new file mode 100644
index 0000000..30f8754
--- /dev/null
+++ b/libavfilter/af_stereowiden.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2012 VLC authors and VideoLAN
+ * Author : Sukrit Sangwan < sukritsangwan at gmail dot 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
+ */
+
+#include "libavutil/channel_layout.h"
+#include "libavutil/opt.h"
+#include "avfilter.h"
+#include "audio.h"
+#include "formats.h"
+
+typedef struct StereoWidenContext {
+ const AVClass *class;
+
+ float delay;
+ float feedback;
+ float crossfeed;
+ float drymix;
+
+ float *buffer;
+ float *write;
+ int length;
+} StereoWidenContext;
+
+#define OFFSET(x) offsetof(StereoWidenContext, x)
+#define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption stereowiden_options[] = {
+ { "delay", "set delay time", OFFSET(delay), AV_OPT_TYPE_FLOAT, {.dbl=20}, 1, 100, A },
+ { "feedback", "set feedback gain", OFFSET(feedback), AV_OPT_TYPE_FLOAT, {.dbl=.3}, 0, 0.9, A },
+ { "crossfeed", "set cross feed", OFFSET(crossfeed), AV_OPT_TYPE_FLOAT, {.dbl=.3}, 0, 0.8, A },
+ { "drymix", "set dry-mix", OFFSET(drymix), AV_OPT_TYPE_FLOAT, {.dbl=.8}, 0, 1.0, A },
+ { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(stereowiden);
+
+static int query_formats(AVFilterContext *ctx)
+{
+ AVFilterFormats *formats = NULL;
+ AVFilterChannelLayouts *layout = NULL;
+
+ ff_add_format(&formats, AV_SAMPLE_FMT_FLT);
+ ff_set_common_formats(ctx, formats);
+ ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO);
+ ff_set_common_channel_layouts(ctx, layout);
+
+ formats = ff_all_samplerates();
+ if (!formats)
+ return AVERROR(ENOMEM);
+ return ff_set_common_samplerates(ctx, formats);
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+ AVFilterContext *ctx = inlink->dst;
+ StereoWidenContext *s = ctx->priv;
+
+ s->length = 2 * s->delay * inlink->sample_rate / 1000;
+ s->buffer = av_calloc(s->length, sizeof(s->buffer));
+ if (!s->buffer)
+ return AVERROR(ENOMEM);
+ s->write = s->buffer;
+
+ return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+ AVFilterContext *ctx = inlink->dst;
+ AVFilterLink *outlink = ctx->outputs[0];
+ StereoWidenContext *s = ctx->priv;
+ const float *src = (const float *)in->data[0];
+ const float drymix = s->drymix;
+ const float crossfeed = s->crossfeed;
+ const float feedback = s->feedback;
+ AVFrame *out = NULL;
+ float *dst;
+ int n;
+
+ if (av_frame_is_writable(in)) {
+ out = in;
+ } else {
+ AVFrame *out = ff_get_audio_buffer(inlink, in->nb_samples);
+ if (!out) {
+ av_frame_free(&in);
+ return AVERROR(ENOMEM);
+ }
+ av_frame_copy_props(out, in);
+ }
+ dst = (float *)out->data[0];
+
+ for (n = 0; n < in->nb_samples; n++, src += 2, dst += 2) {
+ const float left = src[0], right = src[1];
+ float *read = s->write + 2;
+
+ if (read > s->buffer + s->length)
+ read = s->buffer;
+
+ dst[0] = drymix * left - crossfeed * right - feedback * read[1];
+ dst[1] = drymix * right - crossfeed * left - feedback * read[0];
+
+ s->write[0] = left;
+ s->write[1] = right;
+
+ if (s->write == s->buffer + s->length)
+ s->write = s->buffer;
+ else
+ s->write += 2;
+ }
+
+ if (out != in)
+ av_frame_free(&in);
+ return ff_filter_frame(outlink, out);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ StereoWidenContext *s = ctx->priv;
+
+ av_freep(&s->buffer);
+}
+
+static const AVFilterPad inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .filter_frame = filter_frame,
+ .config_props = config_input,
+ },
+ { NULL }
+};
+
+static const AVFilterPad outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ },
+ { NULL }
+};
+
+AVFilter ff_af_stereowiden = {
+ .name = "stereowiden",
+ .description = NULL_IF_CONFIG_SMALL("Apply stereo widening effect."),
+ .query_formats = query_formats,
+ .priv_size = sizeof(StereoWidenContext),
+ .priv_class = &stereowiden_class,
+ .uninit = uninit,
+ .inputs = inputs,
+ .outputs = outputs,
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index c78d79b..89390aa 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -102,6 +102,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(SIDECHAINCOMPRESS, sidechaincompress, af);
REGISTER_FILTER(SILENCEDETECT, silencedetect, af);
REGISTER_FILTER(SILENCEREMOVE, silenceremove, af);
+ REGISTER_FILTER(STEREOWIDEN, stereowiden, af);
REGISTER_FILTER(TREBLE, treble, af);
REGISTER_FILTER(VOLUME, volume, af);
REGISTER_FILTER(VOLUMEDETECT, volumedetect, af);
diff --git a/libavfilter/version.h b/libavfilter/version.h
index e7204bc..b3ad51a 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
#include "libavutil/version.h"
#define LIBAVFILTER_VERSION_MAJOR 6
-#define LIBAVFILTER_VERSION_MINOR 3
+#define LIBAVFILTER_VERSION_MINOR 4
#define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
More information about the ffmpeg-cvslog
mailing list