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af_channelsplit.c
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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"
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;
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 
54 {
55  ChannelSplitContext *s = ctx->priv;
56  int nb_channels;
57  int ret = 0, i;
58 
60  av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
62  ret = AVERROR(EINVAL);
63  goto fail;
64  }
65 
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 
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 
82 {
83  ChannelSplitContext *s = ctx->priv;
84  AVFilterChannelLayouts *in_layouts = NULL;
85  int i, ret;
86 
87  if ((ret = ff_set_common_formats(ctx, ff_planar_sample_fmts())) < 0 ||
89  return ret;
90 
91  if ((ret = ff_add_channel_layout(&in_layouts, s->channel_layout)) < 0 ||
92  (ret = ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts)) < 0)
93  return ret;
94 
95  for (i = 0; i < ctx->nb_outputs; i++) {
96  AVFilterChannelLayouts *out_layouts = NULL;
97  uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, i);
98 
99  if ((ret = ff_add_channel_layout(&out_layouts, channel)) < 0 ||
100  (ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts)) < 0)
101  return ret;
102  }
103 
104  return 0;
105 }
106 
107 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
108 {
109  AVFilterContext *ctx = inlink->dst;
110  int i, ret = 0;
111 
112  for (i = 0; i < ctx->nb_outputs; i++) {
113  AVFrame *buf_out = av_frame_clone(buf);
114 
115  if (!buf_out) {
116  ret = AVERROR(ENOMEM);
117  break;
118  }
119 
120  buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[i];
121  buf_out->channel_layout =
123  av_frame_set_channels(buf_out, 1);
124 
125  ret = ff_filter_frame(ctx->outputs[i], buf_out);
126  if (ret < 0)
127  break;
128  }
129  av_frame_free(&buf);
130  return ret;
131 }
132 
134  {
135  .name = "default",
136  .type = AVMEDIA_TYPE_AUDIO,
137  .filter_frame = filter_frame,
138  },
139  { NULL }
140 };
141 
143  .name = "channelsplit",
144  .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."),
145  .priv_size = sizeof(ChannelSplitContext),
146  .priv_class = &channelsplit_class,
147  .init = init,
149  .inputs = avfilter_af_channelsplit_inputs,
150  .outputs = NULL,
152 };
void av_frame_set_channels(AVFrame *frame, int val)
#define NULL
Definition: coverity.c:32
const char * s
Definition: avisynth_c.h:768
This structure describes decoded (raw) audio or video data.
Definition: frame.h:184
AVOption.
Definition: opt.h:245
Main libavfilter public API header.
enum AVMediaType type
AVFilterPad type.
Definition: internal.h:64
Macro definitions for various function/variable attributes.
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
const char * name
Pad name.
Definition: internal.h:59
uint64_t av_get_channel_layout(const char *name)
Return a channel layout id that matches name, or 0 if no match is found.
AVFilterLink ** inputs
array of pointers to input links
Definition: avfilter.h:315
int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:435
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1180
#define F
#define av_cold
Definition: attributes.h:82
#define A
AVOptions.
#define AVFILTER_FLAG_DYNAMIC_OUTPUTS
The number of the filter outputs is not determined just by AVFilter.outputs.
Definition: avfilter.h:111
#define av_log(a,...)
A filter pad used for either input or output.
Definition: internal.h:53
AVFILTER_DEFINE_CLASS(channelsplit)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:568
int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
Definition: formats.c:343
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:153
unsigned nb_outputs
number of output pads
Definition: avfilter.h:320
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:176
void * priv
private data for use by the filter
Definition: avfilter.h:322
static const AVFilterPad avfilter_af_channelsplit_inputs[]
#define fail()
Definition: checkasm.h:82
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:349
common internal API header
#define OFFSET(x)
audio channel layout utility functions
AVFormatContext * ctx
Definition: movenc.c:48
AVFilterFormats * ff_planar_sample_fmts(void)
Construct a formats list containing all planar sample formats.
Definition: formats.c:382
static const AVFilterPad outputs[]
Definition: af_afftfilt.c:386
AVFrame * av_frame_clone(const AVFrame *src)
Create a new frame that references the same data as src.
Definition: frame.c:471
A list of supported channel layouts.
Definition: formats.h:85
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
static const AVFilterPad inputs[]
Definition: af_afftfilt.c:376
static const AVOption channelsplit_options[]
void * buf
Definition: avisynth_c.h:690
Describe the class of an AVClass context structure.
Definition: log.h:67
Filter definition.
Definition: avfilter.h:144
const char * name
Filter name.
Definition: avfilter.h:148
static av_cold int init(AVFilterContext *ctx)
AVFilterLink ** outputs
array of pointers to output links
Definition: avfilter.h:319
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:395
static int flags
Definition: cpu.c:47
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:198
uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
Get the channel with the given index in channel_layout.
const char * av_get_channel_name(uint64_t channel)
Get the name of a given channel.
static int query_formats(AVFilterContext *ctx)
AVFilter ff_af_channelsplit
An instance of a filter.
Definition: avfilter.h:307
int nb_channels
internal API functions
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:231
static int ff_insert_outpad(AVFilterContext *f, unsigned index, AVFilterPad *p)
Insert a new output pad for the filter.
Definition: internal.h:291
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:556