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2ba45a60 DM |
1 | /* |
2 | * This file is part of FFmpeg. | |
3 | * | |
4 | * FFmpeg 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. | |
8 | * | |
9 | * FFmpeg 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. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with FFmpeg; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
19 | /** | |
20 | * @file | |
21 | * Channel split filter | |
22 | * | |
23 | * Split an audio stream into per-channel streams. | |
24 | */ | |
25 | ||
26 | #include "libavutil/attributes.h" | |
27 | #include "libavutil/channel_layout.h" | |
28 | #include "libavutil/internal.h" | |
29 | #include "libavutil/opt.h" | |
30 | ||
31 | #include "audio.h" | |
32 | #include "avfilter.h" | |
33 | #include "formats.h" | |
34 | #include "internal.h" | |
35 | ||
36 | typedef struct ChannelSplitContext { | |
37 | const AVClass *class; | |
38 | ||
39 | uint64_t channel_layout; | |
40 | char *channel_layout_str; | |
41 | } ChannelSplitContext; | |
42 | ||
43 | #define OFFSET(x) offsetof(ChannelSplitContext, x) | |
44 | #define A AV_OPT_FLAG_AUDIO_PARAM | |
45 | #define F AV_OPT_FLAG_FILTERING_PARAM | |
46 | static const AVOption channelsplit_options[] = { | |
47 | { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A|F }, | |
48 | { NULL } | |
49 | }; | |
50 | ||
51 | AVFILTER_DEFINE_CLASS(channelsplit); | |
52 | ||
53 | static av_cold int init(AVFilterContext *ctx) | |
54 | { | |
55 | ChannelSplitContext *s = ctx->priv; | |
56 | int nb_channels; | |
57 | int ret = 0, i; | |
58 | ||
59 | if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) { | |
60 | av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n", | |
61 | s->channel_layout_str); | |
62 | ret = AVERROR(EINVAL); | |
63 | goto fail; | |
64 | } | |
65 | ||
66 | nb_channels = av_get_channel_layout_nb_channels(s->channel_layout); | |
67 | for (i = 0; i < nb_channels; i++) { | |
68 | uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i); | |
69 | AVFilterPad pad = { 0 }; | |
70 | ||
71 | pad.type = AVMEDIA_TYPE_AUDIO; | |
72 | pad.name = av_get_channel_name(channel); | |
73 | ||
74 | ff_insert_outpad(ctx, i, &pad); | |
75 | } | |
76 | ||
77 | fail: | |
78 | return ret; | |
79 | } | |
80 | ||
81 | static int query_formats(AVFilterContext *ctx) | |
82 | { | |
83 | ChannelSplitContext *s = ctx->priv; | |
84 | AVFilterChannelLayouts *in_layouts = NULL; | |
85 | int i; | |
86 | ||
87 | ff_set_common_formats (ctx, ff_planar_sample_fmts()); | |
88 | ff_set_common_samplerates(ctx, ff_all_samplerates()); | |
89 | ||
90 | ff_add_channel_layout(&in_layouts, s->channel_layout); | |
91 | ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts); | |
92 | ||
93 | for (i = 0; i < ctx->nb_outputs; i++) { | |
94 | AVFilterChannelLayouts *out_layouts = NULL; | |
95 | uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i); | |
96 | ||
97 | ff_add_channel_layout(&out_layouts, channel); | |
98 | ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts); | |
99 | } | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static int filter_frame(AVFilterLink *inlink, AVFrame *buf) | |
105 | { | |
106 | AVFilterContext *ctx = inlink->dst; | |
107 | int i, ret = 0; | |
108 | ||
109 | for (i = 0; i < ctx->nb_outputs; i++) { | |
110 | AVFrame *buf_out = av_frame_clone(buf); | |
111 | ||
112 | if (!buf_out) { | |
113 | ret = AVERROR(ENOMEM); | |
114 | break; | |
115 | } | |
116 | ||
117 | buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i]; | |
118 | buf_out->channel_layout = | |
119 | av_channel_layout_extract_channel(buf->channel_layout, i); | |
120 | av_frame_set_channels(buf_out, 1); | |
121 | ||
122 | ret = ff_filter_frame(ctx->outputs[i], buf_out); | |
123 | if (ret < 0) | |
124 | break; | |
125 | } | |
126 | av_frame_free(&buf); | |
127 | return ret; | |
128 | } | |
129 | ||
130 | static const AVFilterPad avfilter_af_channelsplit_inputs[] = { | |
131 | { | |
132 | .name = "default", | |
133 | .type = AVMEDIA_TYPE_AUDIO, | |
134 | .filter_frame = filter_frame, | |
135 | }, | |
136 | { NULL } | |
137 | }; | |
138 | ||
139 | AVFilter ff_af_channelsplit = { | |
140 | .name = "channelsplit", | |
141 | .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."), | |
142 | .priv_size = sizeof(ChannelSplitContext), | |
143 | .priv_class = &channelsplit_class, | |
144 | .init = init, | |
145 | .query_formats = query_formats, | |
146 | .inputs = avfilter_af_channelsplit_inputs, | |
147 | .outputs = NULL, | |
148 | .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS, | |
149 | }; |