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.
9 * Libav is distributed in the hope that it will be useful,
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/opt.h"
34 typedef struct ChannelSplitContext {
37 uint64_t channel_layout;
38 char *channel_layout_str;
39 } ChannelSplitContext;
41 #define OFFSET(x) offsetof(ChannelSplitContext, x)
42 #define A AV_OPT_FLAG_AUDIO_PARAM
43 static const AVOption channelsplit_options[] = {
44 { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A },
48 AVFILTER_DEFINE_CLASS(channelsplit);
50 static int init(AVFilterContext *ctx, const char *arg)
52 ChannelSplitContext *s = ctx->priv;
56 s->class = &channelsplit_class;
57 av_opt_set_defaults(s);
58 if ((ret = av_set_options_string(s, arg, "=", ":")) < 0) {
59 av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", arg);
62 if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
63 av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
64 s->channel_layout_str);
65 ret = AVERROR(EINVAL);
69 nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);
70 for (i = 0; i < nb_channels; i++) {
71 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
72 AVFilterPad pad = { 0 };
74 pad.type = AVMEDIA_TYPE_AUDIO;
75 pad.name = av_get_channel_name(channel);
77 ff_insert_outpad(ctx, i, &pad);
85 static int query_formats(AVFilterContext *ctx)
87 ChannelSplitContext *s = ctx->priv;
88 AVFilterChannelLayouts *in_layouts = NULL;
91 ff_set_common_formats (ctx, ff_planar_sample_fmts());
92 ff_set_common_samplerates(ctx, ff_all_samplerates());
94 ff_add_channel_layout(&in_layouts, s->channel_layout);
95 ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts);
97 for (i = 0; i < ctx->nb_outputs; i++) {
98 AVFilterChannelLayouts *out_layouts = NULL;
99 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
101 ff_add_channel_layout(&out_layouts, channel);
102 ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts);
108 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
110 AVFilterContext *ctx = inlink->dst;
113 for (i = 0; i < ctx->nb_outputs; i++) {
114 AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE);
119 buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
120 buf_out->audio->channel_layout =
121 av_channel_layout_extract_channel(buf->audio->channel_layout, i);
123 ff_filter_samples(ctx->outputs[i], buf_out);
125 avfilter_unref_buffer(buf);
128 AVFilter avfilter_af_channelsplit = {
129 .name = "channelsplit",
130 .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"),
131 .priv_size = sizeof(ChannelSplitContext),
134 .query_formats = query_formats,
136 .inputs = (const AVFilterPad[]){{ .name = "default",
137 .type = AVMEDIA_TYPE_AUDIO,
138 .filter_samples = filter_samples, },
140 .outputs = (const AVFilterPad[]){{ NULL }},