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/*
* 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
* Channel split filter
*
* Split an audio stream into per-channel streams.
*/
#include "libavutil/attributes.h"
#include "libavutil/channel_layout.h"
#include "libavutil/internal.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
#define F AV_OPT_FLAG_FILTERING_PARAM
static const AVOption channelsplit_options[] = {
{ "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A|F },
{ NULL }
};
AVFILTER_DEFINE_CLASS(channelsplit);
static av_cold int init(AVFilterContext *ctx)
{
ChannelSplitContext *s = ctx->priv;
int nb_channels;
int ret = 0, i;
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:
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->nb_outputs; 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 int filter_frame(AVFilterLink *inlink, AVFrame *buf)
{
AVFilterContext *ctx = inlink->dst;
int i, ret = 0;
for (i = 0; i < ctx->nb_outputs; i++) {
AVFrame *buf_out = av_frame_clone(buf);
if (!buf_out) {
ret = AVERROR(ENOMEM);
break;
}
buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
buf_out->channel_layout =
av_channel_layout_extract_channel(buf->channel_layout, i);
av_frame_set_channels(buf_out, 1);
ret = ff_filter_frame(ctx->outputs[i], buf_out);
if (ret < 0)
break;
}
av_frame_free(&buf);
return ret;
}
static const AVFilterPad avfilter_af_channelsplit_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_AUDIO,
.filter_frame = filter_frame,
},
{ NULL }
};
AVFilter avfilter_af_channelsplit = {
.name = "channelsplit",
.description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."),
.priv_size = sizeof(ChannelSplitContext),
.priv_class = &channelsplit_class,
.init = init,
.query_formats = query_formats,
.inputs = avfilter_af_channelsplit_inputs,
.outputs = NULL,
.flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
};
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