[FFmpeg-cvslog] lavfi: add channelsplit audio filter.
Anton Khirnov
git at videolan.org
Wed Jun 13 23:02:27 CEST 2012
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Wed May 30 13:59:30 2012 +0200| [d6251368772a170987387bdc508433c8fcf54cda] | committer: Anton Khirnov
lavfi: add channelsplit audio filter.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d6251368772a170987387bdc508433c8fcf54cda
---
Changelog | 1 +
doc/filters.texi | 25 +++++++
libavfilter/Makefile | 1 +
libavfilter/af_channelsplit.c | 146 +++++++++++++++++++++++++++++++++++++++++
libavfilter/allfilters.c | 1 +
libavfilter/formats.c | 12 ++++
libavfilter/formats.h | 5 ++
libavfilter/version.h | 2 +-
8 files changed, 192 insertions(+), 1 deletion(-)
diff --git a/Changelog b/Changelog
index 898a247..b80ff88 100644
--- a/Changelog
+++ b/Changelog
@@ -24,6 +24,7 @@ version <next>:
- avprobe output is now standard INI or JSON. The old format can still
be used with -of old.
- Indeo Audio decoder
+- channelsplit audio filter
version 0.8:
diff --git a/doc/filters.texi b/doc/filters.texi
index 0179682..f17dad8 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -207,6 +207,31 @@ Maximum compensation in samples per second.
@end table
+ at section channelsplit
+Split each channel in input audio stream into a separate output stream.
+
+This filter accepts the following named parameters:
+ at table @option
+ at item channel_layout
+Channel layout of the input stream. Default is "stereo".
+ at end table
+
+For example, assuming a stereo input MP3 file
+ at example
+avconv -i in.mp3 -filter_complex channelsplit out.mkv
+ at end example
+will create an output Matroska file with two audio streams, one containing only
+the left channel and the other the right channel.
+
+To split a 5.1 WAV file into per-channel files
+ at example
+avconv -i in.wav -filter_complex
+'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
+-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
+front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
+side_right.wav
+ at end example
+
@section resample
Convert the audio sample format, sample rate and channel layout. This filter is
not meant to be used directly, it is inserted automatically by libavfilter
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 914f0c6..7e1a6d1 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -29,6 +29,7 @@ OBJS-$(CONFIG_AMIX_FILTER) += af_amix.o
OBJS-$(CONFIG_ANULL_FILTER) += af_anull.o
OBJS-$(CONFIG_ASPLIT_FILTER) += split.o
OBJS-$(CONFIG_ASYNCTS_FILTER) += af_asyncts.o
+OBJS-$(CONFIG_CHANNELSPLIT_FILTER) += af_channelsplit.o
OBJS-$(CONFIG_RESAMPLE_FILTER) += af_resample.o
OBJS-$(CONFIG_ANULLSRC_FILTER) += asrc_anullsrc.o
diff --git a/libavfilter/af_channelsplit.c b/libavfilter/af_channelsplit.c
new file mode 100644
index 0000000..c3e7ccf
--- /dev/null
+++ b/libavfilter/af_channelsplit.c
@@ -0,0 +1,146 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Channel split filter
+ *
+ * Split an audio stream into per-channel streams.
+ */
+
+#include "libavutil/audioconvert.h"
+#include "libavutil/opt.h"
+
+#include "audio.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+
+typedef struct ChannelSplitContext {
+ const AVClass *class;
+
+ uint64_t channel_layout;
+ char *channel_layout_str;
+} ChannelSplitContext;
+
+#define OFFSET(x) offsetof(ChannelSplitContext, x)
+#define A AV_OPT_FLAG_AUDIO_PARAM
+static const AVOption options[] = {
+ { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A },
+ { NULL },
+};
+
+static const AVClass channelsplit_class = {
+ .class_name = "channelsplit filter",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+static int init(AVFilterContext *ctx, const char *arg, void *opaque)
+{
+ ChannelSplitContext *s = ctx->priv;
+ int nb_channels;
+ int ret = 0, i;
+
+ s->class = &channelsplit_class;
+ av_opt_set_defaults(s);
+ if ((ret = av_set_options_string(s, arg, "=", ":")) < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", arg);
+ return ret;
+ }
+ if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
+ av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
+ s->channel_layout_str);
+ ret = AVERROR(EINVAL);
+ goto fail;
+ }
+
+ nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);
+ for (i = 0; i < nb_channels; i++) {
+ uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
+ AVFilterPad pad = { 0 };
+
+ pad.type = AVMEDIA_TYPE_AUDIO;
+ pad.name = av_get_channel_name(channel);
+
+ ff_insert_outpad(ctx, i, &pad);
+ }
+
+fail:
+ av_opt_free(s);
+ return ret;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+ ChannelSplitContext *s = ctx->priv;
+ AVFilterChannelLayouts *in_layouts = NULL;
+ int i;
+
+ ff_set_common_formats (ctx, ff_planar_sample_fmts());
+ ff_set_common_samplerates(ctx, ff_all_samplerates());
+
+ ff_add_channel_layout(&in_layouts, s->channel_layout);
+ ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts);
+
+ for (i = 0; i < ctx->output_count; i++) {
+ AVFilterChannelLayouts *out_layouts = NULL;
+ uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
+
+ ff_add_channel_layout(&out_layouts, channel);
+ ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts);
+ }
+
+ return 0;
+}
+
+static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
+{
+ AVFilterContext *ctx = inlink->dst;
+ int i;
+
+ for (i = 0; i < ctx->output_count; i++) {
+ AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE);
+
+ if (!buf_out)
+ return;
+
+ buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
+ buf_out->audio->channel_layout =
+ av_channel_layout_extract_channel(buf->audio->channel_layout, i);
+
+ ff_filter_samples(ctx->outputs[i], buf_out);
+ }
+ avfilter_unref_buffer(buf);
+}
+
+AVFilter avfilter_af_channelsplit = {
+ .name = "channelsplit",
+ .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"),
+ .priv_size = sizeof(ChannelSplitContext),
+
+ .init = init,
+ .query_formats = query_formats,
+
+ .inputs = (const AVFilterPad[]){{ .name = "default",
+ .type = AVMEDIA_TYPE_AUDIO,
+ .filter_samples = filter_samples, },
+ { NULL }},
+ .outputs = (const AVFilterPad[]){{ NULL }},
+};
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 941ca6a..6814871 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -39,6 +39,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (ANULL, anull, af);
REGISTER_FILTER (ASPLIT, asplit, af);
REGISTER_FILTER (ASYNCTS, asyncts, af);
+ REGISTER_FILTER (CHANNELSPLIT,channelsplit,af);
REGISTER_FILTER (RESAMPLE, resample, af);
REGISTER_FILTER (ANULLSRC, anullsrc, asrc);
diff --git a/libavfilter/formats.c b/libavfilter/formats.c
index 83bdcd7..1d58d95 100644
--- a/libavfilter/formats.c
+++ b/libavfilter/formats.c
@@ -220,6 +220,18 @@ AVFilterFormats *ff_all_formats(enum AVMediaType type)
return ret;
}
+AVFilterFormats *ff_planar_sample_fmts(void)
+{
+ AVFilterFormats *ret = NULL;
+ int fmt;
+
+ for (fmt = 0; fmt < AV_SAMPLE_FMT_NB; fmt++)
+ if (av_sample_fmt_is_planar(fmt))
+ ff_add_format(&ret, fmt);
+
+ return ret;
+}
+
AVFilterFormats *ff_all_samplerates(void)
{
AVFilterFormats *ret = av_mallocz(sizeof(*ret));
diff --git a/libavfilter/formats.h b/libavfilter/formats.h
index 8961cb1..c3e9522 100644
--- a/libavfilter/formats.h
+++ b/libavfilter/formats.h
@@ -160,6 +160,11 @@ int ff_add_format(AVFilterFormats **avff, int fmt);
AVFilterFormats *ff_all_formats(enum AVMediaType type);
/**
+ * Construct a formats list containing all planar sample formats.
+ */
+AVFilterFormats *ff_planar_sample_fmts(void);
+
+/**
* Return a format list which contains the intersection of the formats of
* a and b. Also, all the references of a, all the references of b, and
* a and b themselves will be deallocated.
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 9a64316..09cf4c6 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -29,7 +29,7 @@
#include "libavutil/avutil.h"
#define LIBAVFILTER_VERSION_MAJOR 2
-#define LIBAVFILTER_VERSION_MINOR 20
+#define LIBAVFILTER_VERSION_MINOR 21
#define LIBAVFILTER_VERSION_MICRO 0
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
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