FFmpeg  4.4.4
channel_layout.c
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1 /*
2  * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * audio channel layout utility functions
24  */
25 
26 #include <stdint.h>
27 
28 #include "avstring.h"
29 #include "avutil.h"
30 #include "channel_layout.h"
31 #include "bprint.h"
32 #include "common.h"
33 
34 struct channel_name {
35  const char *name;
36  const char *description;
37 };
38 
39 static const struct channel_name channel_names[] = {
40  [0] = { "FL", "front left" },
41  [1] = { "FR", "front right" },
42  [2] = { "FC", "front center" },
43  [3] = { "LFE", "low frequency" },
44  [4] = { "BL", "back left" },
45  [5] = { "BR", "back right" },
46  [6] = { "FLC", "front left-of-center" },
47  [7] = { "FRC", "front right-of-center" },
48  [8] = { "BC", "back center" },
49  [9] = { "SL", "side left" },
50  [10] = { "SR", "side right" },
51  [11] = { "TC", "top center" },
52  [12] = { "TFL", "top front left" },
53  [13] = { "TFC", "top front center" },
54  [14] = { "TFR", "top front right" },
55  [15] = { "TBL", "top back left" },
56  [16] = { "TBC", "top back center" },
57  [17] = { "TBR", "top back right" },
58  [29] = { "DL", "downmix left" },
59  [30] = { "DR", "downmix right" },
60  [31] = { "WL", "wide left" },
61  [32] = { "WR", "wide right" },
62  [33] = { "SDL", "surround direct left" },
63  [34] = { "SDR", "surround direct right" },
64  [35] = { "LFE2", "low frequency 2" },
65  [36] = { "TSL", "top side left" },
66  [37] = { "TSR", "top side right" },
67  [38] = { "BFC", "bottom front center" },
68  [39] = { "BFL", "bottom front left" },
69  [40] = { "BFR", "bottom front right" },
70 };
71 
72 static const char *get_channel_name(int channel_id)
73 {
74  if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
75  return NULL;
76  return channel_names[channel_id].name;
77 }
78 
79 static const struct {
80  const char *name;
82  uint64_t layout;
83 } channel_layout_map[] = {
84  { "mono", 1, AV_CH_LAYOUT_MONO },
85  { "stereo", 2, AV_CH_LAYOUT_STEREO },
86  { "2.1", 3, AV_CH_LAYOUT_2POINT1 },
87  { "3.0", 3, AV_CH_LAYOUT_SURROUND },
88  { "3.0(back)", 3, AV_CH_LAYOUT_2_1 },
89  { "4.0", 4, AV_CH_LAYOUT_4POINT0 },
90  { "quad", 4, AV_CH_LAYOUT_QUAD },
91  { "quad(side)", 4, AV_CH_LAYOUT_2_2 },
92  { "3.1", 4, AV_CH_LAYOUT_3POINT1 },
93  { "5.0", 5, AV_CH_LAYOUT_5POINT0_BACK },
94  { "5.0(side)", 5, AV_CH_LAYOUT_5POINT0 },
95  { "4.1", 5, AV_CH_LAYOUT_4POINT1 },
96  { "5.1", 6, AV_CH_LAYOUT_5POINT1_BACK },
97  { "5.1(side)", 6, AV_CH_LAYOUT_5POINT1 },
98  { "6.0", 6, AV_CH_LAYOUT_6POINT0 },
99  { "6.0(front)", 6, AV_CH_LAYOUT_6POINT0_FRONT },
100  { "hexagonal", 6, AV_CH_LAYOUT_HEXAGONAL },
101  { "6.1", 7, AV_CH_LAYOUT_6POINT1 },
102  { "6.1(back)", 7, AV_CH_LAYOUT_6POINT1_BACK },
103  { "6.1(front)", 7, AV_CH_LAYOUT_6POINT1_FRONT },
104  { "7.0", 7, AV_CH_LAYOUT_7POINT0 },
105  { "7.0(front)", 7, AV_CH_LAYOUT_7POINT0_FRONT },
106  { "7.1", 8, AV_CH_LAYOUT_7POINT1 },
107  { "7.1(wide)", 8, AV_CH_LAYOUT_7POINT1_WIDE_BACK },
108  { "7.1(wide-side)", 8, AV_CH_LAYOUT_7POINT1_WIDE },
109  { "octagonal", 8, AV_CH_LAYOUT_OCTAGONAL },
110  { "hexadecagonal", 16, AV_CH_LAYOUT_HEXADECAGONAL },
111  { "downmix", 2, AV_CH_LAYOUT_STEREO_DOWNMIX, },
112  { "22.2", 24, AV_CH_LAYOUT_22POINT2, },
113 };
114 
115 static uint64_t get_channel_layout_single(const char *name, int name_len)
116 {
117  int i;
118  char *end;
119  int64_t layout;
120 
121  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
122  if (strlen(channel_layout_map[i].name) == name_len &&
123  !memcmp(channel_layout_map[i].name, name, name_len))
124  return channel_layout_map[i].layout;
125  }
126  for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
127  if (channel_names[i].name &&
128  strlen(channel_names[i].name) == name_len &&
129  !memcmp(channel_names[i].name, name, name_len))
130  return (int64_t)1 << i;
131 
132  errno = 0;
133  i = strtol(name, &end, 10);
134 
135  if (!errno && (end + 1 - name == name_len && *end == 'c'))
137 
138  errno = 0;
139  layout = strtoll(name, &end, 0);
140  if (!errno && end - name == name_len)
141  return FFMAX(layout, 0);
142  return 0;
143 }
144 
145 uint64_t av_get_channel_layout(const char *name)
146 {
147  const char *n, *e;
148  const char *name_end = name + strlen(name);
149  int64_t layout = 0, layout_single;
150 
151  for (n = name; n < name_end; n = e + 1) {
152  for (e = n; e < name_end && *e != '+' && *e != '|'; e++);
153  layout_single = get_channel_layout_single(n, e - n);
154  if (!layout_single)
155  return 0;
156  layout |= layout_single;
157  }
158  return layout;
159 }
160 
161 int av_get_extended_channel_layout(const char *name, uint64_t* channel_layout, int* nb_channels)
162 {
163  int nb = 0;
164  char *end;
165  uint64_t layout = av_get_channel_layout(name);
166 
167  if (layout) {
168  *channel_layout = layout;
170  return 0;
171  }
172 
173  nb = strtol(name, &end, 10);
174  if (!errno && *end == 'C' && *(end + 1) == '\0' && nb > 0 && nb < 64) {
175  *channel_layout = 0;
176  *nb_channels = nb;
177  return 0;
178  }
179 
180  return AVERROR(EINVAL);
181 }
182 
183 void av_bprint_channel_layout(struct AVBPrint *bp,
184  int nb_channels, uint64_t channel_layout)
185 {
186  int i;
187 
188  if (nb_channels <= 0)
190 
191  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
193  channel_layout == channel_layout_map[i].layout) {
194  av_bprintf(bp, "%s", channel_layout_map[i].name);
195  return;
196  }
197 
198  av_bprintf(bp, "%d channels", nb_channels);
199  if (channel_layout) {
200  int i, ch;
201  av_bprintf(bp, " (");
202  for (i = 0, ch = 0; i < 64; i++) {
203  if ((channel_layout & (UINT64_C(1) << i))) {
204  const char *name = get_channel_name(i);
205  if (name) {
206  if (ch > 0)
207  av_bprintf(bp, "+");
208  av_bprintf(bp, "%s", name);
209  }
210  ch++;
211  }
212  }
213  av_bprintf(bp, ")");
214  }
215 }
216 
217 void av_get_channel_layout_string(char *buf, int buf_size,
218  int nb_channels, uint64_t channel_layout)
219 {
220  AVBPrint bp;
221 
222  av_bprint_init_for_buffer(&bp, buf, buf_size);
223  av_bprint_channel_layout(&bp, nb_channels, channel_layout);
224 }
225 
226 int av_get_channel_layout_nb_channels(uint64_t channel_layout)
227 {
228  return av_popcount64(channel_layout);
229 }
230 
232  int i;
233  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
235  return channel_layout_map[i].layout;
236  return 0;
237 }
238 
239 int av_get_channel_layout_channel_index(uint64_t channel_layout,
240  uint64_t channel)
241 {
242  if (!(channel_layout & channel) ||
244  return AVERROR(EINVAL);
245  channel_layout &= channel - 1;
246  return av_get_channel_layout_nb_channels(channel_layout);
247 }
248 
249 const char *av_get_channel_name(uint64_t channel)
250 {
251  int i;
253  return NULL;
254  for (i = 0; i < 64; i++)
255  if ((1ULL<<i) & channel)
256  return get_channel_name(i);
257  return NULL;
258 }
259 
260 const char *av_get_channel_description(uint64_t channel)
261 {
262  int i;
264  return NULL;
265  for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
266  if ((1ULL<<i) & channel)
267  return channel_names[i].description;
268  return NULL;
269 }
270 
271 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
272 {
273  int i;
274 
275  if (av_get_channel_layout_nb_channels(channel_layout) <= index)
276  return 0;
277 
278  for (i = 0; i < 64; i++) {
279  if ((1ULL << i) & channel_layout && !index--)
280  return 1ULL << i;
281  }
282  return 0;
283 }
284 
286  const char **name)
287 {
289  return AVERROR_EOF;
290  if (layout) *layout = channel_layout_map[index].layout;
291  if (name) *name = channel_layout_map[index].name;
292  return 0;
293 }
Convenience header that includes libavutil's core.
void av_bprintf(AVBPrint *buf, const char *fmt,...)
Definition: bprint.c:94
void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, unsigned size)
Init a print buffer using a pre-existing buffer.
Definition: bprint.c:85
static const struct channel_name channel_names[]
static const char * get_channel_name(int channel_id)
uint64_t layout
static uint64_t get_channel_layout_single(const char *name, int name_len)
const char * name
static const struct @289 channel_layout_map[]
int nb_channels
audio channel layout utility functions
common internal and external API header
#define av_popcount64
Definition: common.h:179
#define FFMAX(a, b)
Definition: common.h:103
#define NULL
Definition: coverity.c:32
channel
Use these values when setting the channel map with ebur128_set_channel().
Definition: ebur128.h:39
int av_get_standard_channel_layout(unsigned index, uint64_t *layout, const char **name)
Get the value and name of a standard channel layout.
#define AV_CH_LAYOUT_2POINT1
int av_get_channel_layout_channel_index(uint64_t channel_layout, uint64_t channel)
Get the index of a channel in channel_layout.
#define AV_CH_LAYOUT_QUAD
#define AV_CH_LAYOUT_6POINT1
#define AV_CH_LAYOUT_4POINT0
#define AV_CH_LAYOUT_6POINT0
#define AV_CH_LAYOUT_5POINT0
#define AV_CH_LAYOUT_7POINT1
#define AV_CH_LAYOUT_STEREO_DOWNMIX
uint64_t av_get_channel_layout(const char *name)
Return a channel layout id that matches name, or 0 if no match is found.
#define AV_CH_LAYOUT_HEXAGONAL
void av_bprint_channel_layout(struct AVBPrint *bp, int nb_channels, uint64_t channel_layout)
Append a description of a channel layout to a bprint buffer.
#define AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_2_2
#define AV_CH_LAYOUT_SURROUND
#define AV_CH_LAYOUT_6POINT0_FRONT
#define AV_CH_LAYOUT_7POINT1_WIDE
#define AV_CH_LAYOUT_6POINT1_FRONT
#define AV_CH_LAYOUT_7POINT1_WIDE_BACK
void av_get_channel_layout_string(char *buf, int buf_size, int nb_channels, uint64_t channel_layout)
Return a description of a channel layout.
#define AV_CH_LAYOUT_7POINT0_FRONT
#define AV_CH_LAYOUT_OCTAGONAL
#define AV_CH_LAYOUT_6POINT1_BACK
#define AV_CH_LAYOUT_5POINT0_BACK
#define AV_CH_LAYOUT_7POINT0
#define AV_CH_LAYOUT_STEREO
#define AV_CH_LAYOUT_22POINT2
#define AV_CH_LAYOUT_5POINT1
int av_get_channel_layout_nb_channels(uint64_t channel_layout)
Return the number of channels in the channel layout.
int64_t av_get_default_channel_layout(int nb_channels)
Return default channel layout for a given number of channels.
#define AV_CH_LAYOUT_4POINT1
#define AV_CH_LAYOUT_2_1
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.
const char * av_get_channel_description(uint64_t channel)
Get the description of a given channel.
#define AV_CH_LAYOUT_3POINT1
#define AV_CH_LAYOUT_5POINT1_BACK
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.
#define AV_CH_LAYOUT_HEXADECAGONAL
#define AVERROR_EOF
End of file.
Definition: error.h:55
#define AVERROR(e)
Definition: error.h:43
int index
Definition: gxfenc.c:89
int i
Definition: input.c:407
#define FF_ARRAY_ELEMS(a)
const char * description
const char * name