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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/mem.h"
#include "libavutil/opt.h"
#include "audio.h"
#include "avfilter.h"
#include "filters.h"
#include "formats.h"
#include "internal.h"
#define MAX_CH 64
typedef struct ChannelSplitContext {
const AVClass *class;
AVChannelLayout channel_layout;
char *channels_str;
int map[64];
} 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), AV_OPT_TYPE_CHLAYOUT, { .str = "stereo" }, .flags = A|F },
{ "channels", "Channels to extract.", OFFSET(channels_str), AV_OPT_TYPE_STRING, { .str = "all" }, .flags = A|F },
{ NULL }
};
AVFILTER_DEFINE_CLASS(channelsplit);
static av_cold int init(AVFilterContext *ctx)
{
ChannelSplitContext *s = ctx->priv;
AVChannelLayout channel_layout = { 0 };
int all = 0, ret = 0, i;
if (!strcmp(s->channels_str, "all")) {
if ((ret = av_channel_layout_copy(&channel_layout, &s->channel_layout)) < 0)
goto fail;
all = 1;
} else {
if ((ret = av_channel_layout_from_string(&channel_layout, s->channels_str)) < 0)
goto fail;
}
if (channel_layout.nb_channels > MAX_CH) {
av_log(ctx, AV_LOG_ERROR, "Too many channels\n");
goto fail;
}
for (i = 0; i < channel_layout.nb_channels; i++) {
enum AVChannel channel = av_channel_layout_channel_from_index(&channel_layout, i);
char buf[64];
AVFilterPad pad = { .flags = AVFILTERPAD_FLAG_FREE_NAME };
av_channel_name(buf, sizeof(buf), channel);
pad.type = AVMEDIA_TYPE_AUDIO;
pad.name = av_strdup(buf);
if (!pad.name) {
ret = AVERROR(ENOMEM);
goto fail;
}
if (all) {
s->map[i] = i;
} else {
char buf[128];
av_channel_layout_describe(&s->channel_layout, buf, sizeof(buf));
if ((ret = av_channel_layout_index_from_channel(&s->channel_layout, channel)) < 0) {
av_log(ctx, AV_LOG_ERROR, "Channel name '%s' not present in channel layout '%s'.\n",
pad.name, buf);
av_freep(&pad.name);
goto fail;
}
s->map[i] = ret;
}
if ((ret = ff_append_outpad(ctx, &pad)) < 0)
goto fail;
}
fail:
av_channel_layout_uninit(&channel_layout);
return ret;
}
static av_cold void uninit(AVFilterContext *ctx)
{
ChannelSplitContext *s = ctx->priv;
av_channel_layout_uninit(&s->channel_layout);
}
static int query_formats(AVFilterContext *ctx)
{
ChannelSplitContext *s = ctx->priv;
AVFilterChannelLayouts *in_layouts = NULL;
int i, ret;
if ((ret = ff_set_common_formats(ctx, ff_planar_sample_fmts())) < 0 ||
(ret = ff_set_common_all_samplerates(ctx)) < 0)
return ret;
if ((ret = ff_add_channel_layout(&in_layouts, &s->channel_layout)) < 0 ||
(ret = ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->outcfg.channel_layouts)) < 0)
return ret;
for (i = 0; i < ctx->nb_outputs; i++) {
AVChannelLayout channel_layout = { 0 };
AVFilterChannelLayouts *out_layouts = NULL;
enum AVChannel channel = av_channel_layout_channel_from_index(&s->channel_layout, s->map[i]);
if ((ret = av_channel_layout_from_mask(&channel_layout, 1ULL << channel)) < 0 ||
(ret = ff_add_channel_layout(&out_layouts, &channel_layout)) < 0 ||
(ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->incfg.channel_layouts)) < 0)
return ret;
}
return 0;
}
static int filter_frame(AVFilterLink *outlink, AVFrame *buf)
{
AVFilterContext *ctx = outlink->src;
ChannelSplitContext *s = ctx->priv;
const int i = FF_OUTLINK_IDX(outlink);
enum AVChannel channel = av_channel_layout_channel_from_index(&buf->ch_layout, s->map[i]);
int ret;
AVFrame *buf_out = av_frame_clone(buf);
if (!buf_out)
return AVERROR(ENOMEM);
buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[s->map[i]];
ret = av_channel_layout_from_mask(&buf_out->ch_layout, 1ULL << channel);
if (ret < 0)
return ret;
return ff_filter_frame(ctx->outputs[i], buf_out);
}
static int activate(AVFilterContext *ctx)
{
AVFilterLink *inlink = ctx->inputs[0];
int status, ret;
AVFrame *in;
int64_t pts;
for (int i = 0; i < ctx->nb_outputs; i++) {
FF_FILTER_FORWARD_STATUS_BACK_ALL(ctx->outputs[i], ctx);
}
ret = ff_inlink_consume_frame(inlink, &in);
if (ret < 0)
return ret;
if (ret > 0) {
for (int i = 0; i < ctx->nb_outputs; i++) {
if (ff_outlink_get_status(ctx->outputs[i]))
continue;
ret = filter_frame(ctx->outputs[i], in);
if (ret < 0)
break;
}
av_frame_free(&in);
if (ret < 0)
return ret;
}
if (ff_inlink_acknowledge_status(inlink, &status, &pts)) {
for (int i = 0; i < ctx->nb_outputs; i++) {
if (ff_outlink_get_status(ctx->outputs[i]))
continue;
ff_outlink_set_status(ctx->outputs[i], status, pts);
}
return 0;
}
for (int i = 0; i < ctx->nb_outputs; i++) {
if (ff_outlink_get_status(ctx->outputs[i]))
continue;
if (ff_outlink_frame_wanted(ctx->outputs[i])) {
ff_inlink_request_frame(inlink);
return 0;
}
}
return FFERROR_NOT_READY;
}
const AVFilter ff_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,
.activate = activate,
.uninit = uninit,
FILTER_INPUTS(ff_audio_default_filterpad),
.outputs = NULL,
FILTER_QUERY_FUNC(query_formats),
.flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
};
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