/*

* 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 {

} 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 },

{ "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;

uint64_t channel_layout;

int nb_channels;

int all = 0, 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;

}

if (!strcmp(s->channels_str, "all")) {

nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);

channel_layout = s->channel_layout;

all = 1;

} else {

if ((ret = av_get_extended_channel_layout(s->channels_str, &channel_layout, &nb_channels)) < 0)

return ret;

}

for (i = 0; i < nb_channels; i++) {

uint64_t channel = av_channel_layout_extract_channel(channel_layout, i);

AVFilterPad pad = { 0 };

pad.type = AVMEDIA_TYPE_AUDIO;

pad.name = av_get_channel_name(channel);

if (all) {

s->map[i] = i;

} else {

if ((ret = av_get_channel_layout_channel_index(s->channel_layout, channel)) < 0) {

av_log(ctx, AV_LOG_ERROR, "Channel name '%s' not present in channel layout '%s'.\n",

av_get_channel_name(channel), s->channel_layout_str);

return ret;

}

s->map[i] = ret;

}

if ((ret = ff_insert_outpad(ctx, i, &pad)) < 0) {

return ret;

}

}

fail:

return ret;

}

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_samplerates(ctx, ff_all_samplerates())) < 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]->out_channel_layouts)) < 0)

return ret;

for (i = 0; i < ctx->nb_outputs; i++) {

AVFilterChannelLayouts *out_layouts = NULL;

uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, s->map[i]);

if ((ret = ff_add_channel_layout(&out_layouts, channel)) < 0 ||

(ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts)) < 0)

return ret;

}

return 0;

}

static int filter_frame(AVFilterLink *inlink, AVFrame *buf)

{

AVFilterContext *ctx = inlink->dst;

ChannelSplitContext *s = ctx->priv;

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[s->map[i]];

buf_out->channel_layout =

av_channel_layout_extract_channel(buf->channel_layout, s->map[i]);

buf_out->channels = 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 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,

.query_formats = query_formats,

.inputs = avfilter_af_channelsplit_inputs,

.outputs = NULL,

.flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS,

};