yading@10: /*
yading@10:  * This file is part of Libav.
yading@10:  *
yading@10:  * Libav is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * Libav is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with Libav; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Channel split filter
yading@10:  *
yading@10:  * Split an audio stream into per-channel streams.
yading@10:  */
yading@10: 
yading@10: #include "libavutil/channel_layout.h"
yading@10: #include "libavutil/internal.h"
yading@10: #include "libavutil/opt.h"
yading@10: 
yading@10: #include "audio.h"
yading@10: #include "avfilter.h"
yading@10: #include "formats.h"
yading@10: #include "internal.h"
yading@10: 
yading@10: typedef struct ChannelSplitContext {
yading@10:     const AVClass *class;
yading@10: 
yading@10:     uint64_t channel_layout;
yading@10:     char    *channel_layout_str;
yading@10: } ChannelSplitContext;
yading@10: 
yading@10: #define OFFSET(x) offsetof(ChannelSplitContext, x)
yading@10: #define A AV_OPT_FLAG_AUDIO_PARAM
yading@10: #define F AV_OPT_FLAG_FILTERING_PARAM
yading@10: static const AVOption channelsplit_options[] = {
yading@10:     { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A|F },
yading@10:     { NULL },
yading@10: };
yading@10: 
yading@10: AVFILTER_DEFINE_CLASS(channelsplit);
yading@10: 
yading@10: static int init(AVFilterContext *ctx)
yading@10: {
yading@10:     ChannelSplitContext *s = ctx->priv;
yading@10:     int nb_channels;
yading@10:     int ret = 0, i;
yading@10: 
yading@10:     if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
yading@10:         av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
yading@10:                s->channel_layout_str);
yading@10:         ret = AVERROR(EINVAL);
yading@10:         goto fail;
yading@10:     }
yading@10: 
yading@10:     nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);
yading@10:     for (i = 0; i < nb_channels; i++) {
yading@10:         uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
yading@10:         AVFilterPad pad  = { 0 };
yading@10: 
yading@10:         pad.type = AVMEDIA_TYPE_AUDIO;
yading@10:         pad.name = av_get_channel_name(channel);
yading@10: 
yading@10:         ff_insert_outpad(ctx, i, &pad);
yading@10:     }
yading@10: 
yading@10: fail:
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static int query_formats(AVFilterContext *ctx)
yading@10: {
yading@10:     ChannelSplitContext *s = ctx->priv;
yading@10:     AVFilterChannelLayouts *in_layouts = NULL;
yading@10:     int i;
yading@10: 
yading@10:     ff_set_common_formats    (ctx, ff_planar_sample_fmts());
yading@10:     ff_set_common_samplerates(ctx, ff_all_samplerates());
yading@10: 
yading@10:     ff_add_channel_layout(&in_layouts, s->channel_layout);
yading@10:     ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts);
yading@10: 
yading@10:     for (i = 0; i < ctx->nb_outputs; i++) {
yading@10:         AVFilterChannelLayouts *out_layouts = NULL;
yading@10:         uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
yading@10: 
yading@10:         ff_add_channel_layout(&out_layouts, channel);
yading@10:         ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts);
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
yading@10: {
yading@10:     AVFilterContext *ctx = inlink->dst;
yading@10:     int i, ret = 0;
yading@10: 
yading@10:     for (i = 0; i < ctx->nb_outputs; i++) {
yading@10:         AVFrame *buf_out = av_frame_clone(buf);
yading@10: 
yading@10:         if (!buf_out) {
yading@10:             ret = AVERROR(ENOMEM);
yading@10:             break;
yading@10:         }
yading@10: 
yading@10:         buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
yading@10:         buf_out->channel_layout =
yading@10:             av_channel_layout_extract_channel(buf->channel_layout, i);
yading@10:         av_frame_set_channels(buf_out, 1);
yading@10: 
yading@10:         ret = ff_filter_frame(ctx->outputs[i], buf_out);
yading@10:         if (ret < 0)
yading@10:             break;
yading@10:     }
yading@10:     av_frame_free(&buf);
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static const AVFilterPad avfilter_af_channelsplit_inputs[] = {
yading@10:     {
yading@10:         .name           = "default",
yading@10:         .type           = AVMEDIA_TYPE_AUDIO,
yading@10:         .filter_frame   = filter_frame,
yading@10:     },
yading@10:     { NULL }
yading@10: };
yading@10: 
yading@10: AVFilter avfilter_af_channelsplit = {
yading@10:     .name           = "channelsplit",
yading@10:     .description    = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."),
yading@10:     .priv_size      = sizeof(ChannelSplitContext),
yading@10:     .priv_class     = &channelsplit_class,
yading@10: 
yading@10:     .init           = init,
yading@10:     .query_formats  = query_formats,
yading@10: 
yading@10:     .inputs  = avfilter_af_channelsplit_inputs,
yading@10:     .outputs = NULL,
yading@10: 
yading@10:     .flags   = AVFILTER_FLAG_DYNAMIC_OUTPUTS,
yading@10: };