FFmpeg
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,
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11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
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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;
41  char *channels_str;
42 
43  int map[64];
45 
46 #define OFFSET(x) offsetof(ChannelSplitContext, x)
47 #define A AV_OPT_FLAG_AUDIO_PARAM
48 #define F AV_OPT_FLAG_FILTERING_PARAM
49 static const AVOption channelsplit_options[] = {
50  { "channel_layout", "Input channel layout.", OFFSET(channel_layout_str), AV_OPT_TYPE_STRING, { .str = "stereo" }, .flags = A|F },
51  { "channels", "Channels to extract.", OFFSET(channels_str), AV_OPT_TYPE_STRING, { .str = "all" }, .flags = A|F },
52  { NULL }
53 };
54 
55 AVFILTER_DEFINE_CLASS(channelsplit);
56 
58 {
59  ChannelSplitContext *s = ctx->priv;
60  uint64_t channel_layout;
61  int nb_channels;
62  int all = 0, ret = 0, i;
63 
65  av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
67  ret = AVERROR(EINVAL);
68  goto fail;
69  }
70 
71 
72  if (!strcmp(s->channels_str, "all")) {
74  channel_layout = s->channel_layout;
75  all = 1;
76  } else {
77  if ((ret = av_get_extended_channel_layout(s->channels_str, &channel_layout, &nb_channels)) < 0)
78  return ret;
79  }
80 
81  for (i = 0; i < nb_channels; i++) {
82  uint64_t channel = av_channel_layout_extract_channel(channel_layout, i);
83  AVFilterPad pad = { 0 };
84 
86  pad.name = av_get_channel_name(channel);
87 
88  if (all) {
89  s->map[i] = i;
90  } else {
91  if ((ret = av_get_channel_layout_channel_index(s->channel_layout, channel)) < 0) {
92  av_log(ctx, AV_LOG_ERROR, "Channel name '%s' not present in channel layout '%s'.\n",
94  return ret;
95  }
96 
97  s->map[i] = ret;
98  }
99 
100  if ((ret = ff_insert_outpad(ctx, i, &pad)) < 0) {
101  return ret;
102  }
103  }
104 
105 fail:
106  return ret;
107 }
108 
110 {
111  ChannelSplitContext *s = ctx->priv;
112  AVFilterChannelLayouts *in_layouts = NULL;
113  int i, ret;
114 
115  if ((ret = ff_set_common_formats(ctx, ff_planar_sample_fmts())) < 0 ||
116  (ret = ff_set_common_samplerates(ctx, ff_all_samplerates())) < 0)
117  return ret;
118 
119  if ((ret = ff_add_channel_layout(&in_layouts, s->channel_layout)) < 0 ||
120  (ret = ff_channel_layouts_ref(in_layouts, &ctx->inputs[0]->out_channel_layouts)) < 0)
121  return ret;
122 
123  for (i = 0; i < ctx->nb_outputs; i++) {
124  AVFilterChannelLayouts *out_layouts = NULL;
126 
127  if ((ret = ff_add_channel_layout(&out_layouts, channel)) < 0 ||
128  (ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->in_channel_layouts)) < 0)
129  return ret;
130  }
131 
132  return 0;
133 }
134 
136 {
137  AVFilterContext *ctx = inlink->dst;
138  ChannelSplitContext *s = ctx->priv;
139  int i, ret = 0;
140 
141  for (i = 0; i < ctx->nb_outputs; i++) {
142  AVFrame *buf_out = av_frame_clone(buf);
143 
144  if (!buf_out) {
145  ret = AVERROR(ENOMEM);
146  break;
147  }
148 
149  buf_out->data[0] = buf_out->extended_data[0] = buf_out->extended_data[s->map[i]];
150  buf_out->channel_layout =
152  buf_out->channels = 1;
153 
154  ret = ff_filter_frame(ctx->outputs[i], buf_out);
155  if (ret < 0)
156  break;
157  }
158  av_frame_free(&buf);
159  return ret;
160 }
161 
163  {
164  .name = "default",
165  .type = AVMEDIA_TYPE_AUDIO,
166  .filter_frame = filter_frame,
167  },
168  { NULL }
169 };
170 
172  .name = "channelsplit",
173  .description = NULL_IF_CONFIG_SMALL("Split audio into per-channel streams."),
174  .priv_size = sizeof(ChannelSplitContext),
175  .priv_class = &channelsplit_class,
176  .init = init,
178  .inputs = avfilter_af_channelsplit_inputs,
179  .outputs = NULL,
181 };
#define NULL
Definition: coverity.c:32
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
AVOption.
Definition: opt.h:246
Main libavfilter public API header.
enum AVMediaType type
AVFilterPad type.
Definition: internal.h:65
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:60
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:346
int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:434
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1093
#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:54
AVFILTER_DEFINE_CLASS(channelsplit)
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#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:569
int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
Definition: formats.c:342
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:202
unsigned nb_outputs
number of output pads
Definition: avfilter.h:351
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
void * priv
private data for use by the filter
Definition: avfilter.h:353
static const AVFilterPad avfilter_af_channelsplit_inputs[]
#define fail()
Definition: checkasm.h:122
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:472
common internal API header
#define OFFSET(x)
int channels
number of audio channels, only used for audio.
Definition: frame.h:601
audio channel layout utility functions
AVFormatContext * ctx
Definition: movenc.c:48
#define s(width, name)
Definition: cbs_vp9.c:257
AVFilterFormats * ff_planar_sample_fmts(void)
Construct a formats list containing all planar sample formats.
Definition: formats.c:381
AVFrame * av_frame_clone(const AVFrame *src)
Create a new frame that references the same data as src.
Definition: frame.c:540
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
A list of supported channel layouts.
Definition: formats.h:85
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
static const AVOption channelsplit_options[]
void * buf
Definition: avisynth_c.h:766
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
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:350
int av_get_channel_layout_channel_index(uint64_t channel_layout, uint64_t channel)
Get the index of a channel in channel_layout.
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:394
#define flags(name, subs,...)
Definition: cbs_av1.c:561
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:309
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
Get the channel with the given index in channel_layout.
channel
Use these values when setting the channel map with ebur128_set_channel().
Definition: ebur128.h:39
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:338
int nb_channels
internal API functions
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:342
static int ff_insert_outpad(AVFilterContext *f, unsigned index, AVFilterPad *p)
Insert a new output pad for the filter.
Definition: internal.h:285
int av_get_extended_channel_layout(const char *name, uint64_t *channel_layout, int *nb_channels)
Return a channel layout and the number of channels based on the specified name.
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:557