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
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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.
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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 
64  if (!(s->channel_layout = av_get_channel_layout(s->channel_layout_str))) {
65  av_log(ctx, AV_LOG_ERROR, "Error parsing channel layout '%s'.\n",
66  s->channel_layout_str);
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 
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",
93  av_get_channel_name(channel), s->channel_layout_str);
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 
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]->outcfg.channel_layouts)) < 0)
121  return ret;
122 
123  for (i = 0; i < ctx->nb_outputs; i++) {
124  AVFilterChannelLayouts *out_layouts = NULL;
125  uint64_t channel = av_channel_layout_extract_channel(s->channel_layout, s->map[i]);
126 
127  if ((ret = ff_add_channel_layout(&out_layouts, channel)) < 0 ||
128  (ret = ff_channel_layouts_ref(out_layouts, &ctx->outputs[i]->incfg.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,
179  .outputs = NULL,
181 };
AVFilterChannelLayouts
A list of supported channel layouts.
Definition: formats.h:86
AVERROR
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
opt.h
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1094
ff_channel_layouts_ref
int ff_channel_layouts_ref(AVFilterChannelLayouts *f, AVFilterChannelLayouts **ref)
Add *ref as a new reference to f.
Definition: formats.c:461
inlink
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
Definition: filter_design.txt:212
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:204
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:324
AVOption
AVOption.
Definition: opt.h:248
ChannelSplitContext::channel_layout_str
char * channel_layout_str
Definition: af_channelsplit.c:40
av_get_channel_layout
uint64_t av_get_channel_layout(const char *name)
Return a channel layout id that matches name, or 0 if no match is found.
Definition: channel_layout.c:145
AVFilter::name
const char * name
Filter name.
Definition: avfilter.h:149
AVFrame::data
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:338
formats.h
fail
#define fail()
Definition: checkasm.h:133
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:54
F
#define F
Definition: af_channelsplit.c:48
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
av_cold
#define av_cold
Definition: attributes.h:90
inputs
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
Definition: filter_design.txt:243
A
#define A
Definition: af_channelsplit.c:47
ff_set_common_formats
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:587
AVFILTER_DEFINE_CLASS
AVFILTER_DEFINE_CLASS(channelsplit)
ff_add_channel_layout
int ff_add_channel_layout(AVFilterChannelLayouts **l, uint64_t channel_layout)
Definition: formats.c:338
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVFrame::channels
int channels
number of audio channels, only used for audio.
Definition: frame.h:630
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
OFFSET
#define OFFSET(x)
Definition: af_channelsplit.c:46
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
av_get_channel_name
const char * av_get_channel_name(uint64_t channel)
Get the name of a given channel.
Definition: channel_layout.c:249
ctx
AVFormatContext * ctx
Definition: movenc.c:48
av_frame_clone
AVFrame * av_frame_clone(const AVFrame *src)
Create a new frame that references the same data as src.
Definition: frame.c:541
ChannelSplitContext
Definition: af_channelsplit.c:36
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
NULL
#define NULL
Definition: coverity.c:32
avfilter_af_channelsplit_inputs
static const AVFilterPad avfilter_af_channelsplit_inputs[]
Definition: af_channelsplit.c:162
av_get_channel_layout_nb_channels
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
Definition: channel_layout.c:226
AVFILTER_FLAG_DYNAMIC_OUTPUTS
#define AVFILTER_FLAG_DYNAMIC_OUTPUTS
The number of the filter outputs is not determined just by AVFilter.outputs.
Definition: avfilter.h:112
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AVFrame::channel_layout
uint64_t channel_layout
Channel layout of the audio data.
Definition: frame.h:501
attributes.h
init
static av_cold int init(AVFilterContext *ctx)
Definition: af_channelsplit.c:57
internal.h
i
int i
Definition: input.c:407
av_channel_layout_extract_channel
uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
Get the channel with the given index in channel_layout.
Definition: channel_layout.c:271
channelsplit_options
static const AVOption channelsplit_options[]
Definition: af_channelsplit.c:49
internal.h
AVFrame::extended_data
uint8_t ** extended_data
pointers to the data planes/channels.
Definition: frame.h:371
av_get_channel_layout_channel_index
int av_get_channel_layout_channel_index(uint64_t channel_layout, uint64_t channel)
Get the index of a channel in channel_layout.
Definition: channel_layout.c:239
ff_planar_sample_fmts
AVFilterFormats * ff_planar_sample_fmts(void)
Construct a formats list containing all planar sample formats.
Definition: formats.c:408
AVFilterPad::name
const char * name
Pad name.
Definition: internal.h:60
AVFilter
Filter definition.
Definition: avfilter.h:145
ret
ret
Definition: filter_design.txt:187
AVFilterPad::type
enum AVMediaType type
AVFilterPad type.
Definition: internal.h:65
ff_af_channelsplit
AVFilter ff_af_channelsplit
Definition: af_channelsplit.c:171
ff_all_samplerates
AVFilterFormats * ff_all_samplerates(void)
Definition: formats.c:421
channel_layout.h
ChannelSplitContext::channels_str
char * channels_str
Definition: af_channelsplit.c:41
ff_insert_outpad
static int ff_insert_outpad(AVFilterContext *f, unsigned index, AVFilterPad *p)
Insert a new output pad for the filter.
Definition: internal.h:248
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
Definition: af_channelsplit.c:135
avfilter.h
av_get_extended_channel_layout
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.
Definition: channel_layout.c:161
AVFilterContext
An instance of a filter.
Definition: avfilter.h:341
ChannelSplitContext::map
int map[64]
Definition: af_channelsplit.c:43
audio.h
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
ff_set_common_samplerates
int ff_set_common_samplerates(AVFilterContext *ctx, AVFilterFormats *samplerates)
Definition: formats.c:575
AV_OPT_TYPE_STRING
@ AV_OPT_TYPE_STRING
Definition: opt.h:229
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: af_channelsplit.c:109
ChannelSplitContext::channel_layout
uint64_t channel_layout
Definition: af_channelsplit.c:39
channel
channel
Definition: ebur128.h:39
nb_channels
int nb_channels
Definition: channel_layout.c:81