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/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 options[] = {
44 { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A },
48 static const AVClass channelsplit_class = {
49 .class_name = "channelsplit filter",
50 .item_name = av_default_item_name,
52 .version = LIBAVUTIL_VERSION_INT,
55 static int init(AVFilterContext *ctx, const char *arg, void *opaque)
57 ChannelSplitContext *s = ctx->priv;
61 s->class = &channelsplit_class;
62 av_opt_set_defaults(s);
63 if ((ret = av_set_options_string(s, arg, "=", ":")) < 0) {
64 av_log(ctx, AV_LOG_ERROR, "Error parsing options string '%s'.\n", arg);
67 if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
68 av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
69 s->channel_layout_str);
70 ret = AVERROR(EINVAL);
74 nb_channels = av_get_channel_layout_nb_channels(s->channel_layout);
75 for (i = 0; i < nb_channels; i++) {
76 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
77 AVFilterPad pad = { 0 };
79 pad.type = AVMEDIA_TYPE_AUDIO;
80 pad.name = av_get_channel_name(channel);
82 ff_insert_outpad(ctx, i, &pad);
90 static int query_formats(AVFilterContext *ctx)
92 ChannelSplitContext *s = ctx->priv;
93 AVFilterChannelLayouts *in_layouts = NULL;
96 ff_set_common_formats (ctx, ff_planar_sample_fmts());
97 ff_set_common_samplerates(ctx, ff_all_samplerates());
99 ff_add_channel_layout(&in_layouts, s->channel_layout);
100 ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts);
102 for (i = 0; i < ctx->nb_outputs; i++) {
103 AVFilterChannelLayouts *out_layouts = NULL;
104 uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
106 ff_add_channel_layout(&out_layouts, channel);
107 ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts);
113 static void filter_samples(AVFilterLink *inlink, AVFilterBufferRef *buf)
115 AVFilterContext *ctx = inlink->dst;
118 for (i = 0; i < ctx->nb_outputs; i++) {
119 AVFilterBufferRef *buf_out = avfilter_ref_buffer(buf, ~AV_PERM_WRITE);
124 buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
125 buf_out->audio->channel_layout =
126 av_channel_layout_extract_channel(buf->audio->channel_layout, i);
128 ff_filter_samples(ctx->outputs[i], buf_out);
130 avfilter_unref_buffer(buf);
133 AVFilter avfilter_af_channelsplit = {
134 .name = "channelsplit",
135 .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams"),
136 .priv_size = sizeof(ChannelSplitContext),
139 .query_formats = query_formats,
141 .inputs = (const AVFilterPad[]){{ .name = "default",
142 .type = AVMEDIA_TYPE_AUDIO,
143 .filter_samples = filter_samples, },
145 .outputs = (const AVFilterPad[]){{ NULL }},