2 * This file is part of Libav.
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
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10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 * Channel split filter
23 * Split an audio stream into per-channel streams.
26 #include "libavutil/audioconvert.h"
27 #include "libavutil/internal.h"
28 #include "libavutil/opt.h"
35 typedef struct ChannelSplitContext {
38 uint64_t channel_layout;
39 char *channel_layout_str;
40 } ChannelSplitContext;
42 #define OFFSET(x) offsetof(ChannelSplitContext, x)
43 #define A AV_OPT_FLAG_AUDIO_PARAM
44 static const AVOption options[] = {
45 { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A },
49 static const AVClass channelsplit_class = {
50 .class_name = "channelsplit filter",
51 .item_name = av_default_item_name,
53 .version = LIBAVUTIL_VERSION_INT,
56 static int init(AVFilterContext *ctx, const char *arg)
58 ChannelSplitContext *s = ctx->priv;
62 s->class = &channelsplit_class;
63 av_opt_set_defaults(s);
64 if ((ret = av_set_options_string(s, arg, "=", ":")) < 0) {
65 av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", arg);
68 if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
69 av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
70 s->channel_layout_str);
71 ret = AVERROR(EINVAL);
75 nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);
76 for (i = 0; i < nb_channels; i++) {
77 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
78 AVFilterPad pad = { 0 };
80 pad.type = AVMEDIA_TYPE_AUDIO;
81 pad.name = av_get_channel_name(channel);
83 ff_insert_outpad(ctx, i, &pad);
91 static int query_formats(AVFilterContext *ctx)
93 ChannelSplitContext *s = ctx->priv;
94 AVFilterChannelLayouts *in_layouts = NULL;
97 ff_set_common_formats (ctx, ff_planar_sample_fmts());
98 ff_set_common_samplerates(ctx, ff_all_samplerates());
100 ff_add_channel_layout(&in_layouts, s->channel_layout);
101 ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts);
103 for (i = 0; i < ctx->nb_outputs; i++) {
104 AVFilterChannelLayouts *out_layouts = NULL;
105 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
107 ff_add_channel_layout(&out_layouts, channel);
108 ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts);
114 static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
116 AVFilterContext *ctx = inlink->dst;
119 for (i = 0; i < ctx->nb_outputs; i++) {
120 AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE);
123 ret = AVERROR(ENOMEM);
127 buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
128 buf_out->audio->channel_layout =
129 av_channel_layout_extract_channel(buf->audio->channel_layout, i);
131 ret = ff_filter_samples(ctx->outputs[i], buf_out);
135 avfilter_unref_buffer(buf);
139 static const AVFilterPad avfilter_af_channelsplit_inputs[] = {
142 .type = AVMEDIA_TYPE_AUDIO,
143 .filter_samples = filter_samples,
148 AVFilter avfilter_af_channelsplit = {
149 .name = "channelsplit",
150 .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"),
151 .priv_size = sizeof(ChannelSplitContext),
154 .query_formats = query_formats,
156 .inputs = avfilter_af_channelsplit_inputs,