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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 };
66 
67 static const char *get_channel_name(int channel_id)
68 {
69  if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
70  return NULL;
71  return channel_names[channel_id].name;
72 }
73 
74 static const struct {
75  const char *name;
76  int nb_channels;
77  uint64_t layout;
78 } channel_layout_map[] = {
79  { "mono", 1, AV_CH_LAYOUT_MONO },
80  { "stereo", 2, AV_CH_LAYOUT_STEREO },
81  { "2.1", 3, AV_CH_LAYOUT_2POINT1 },
82  { "3.0", 3, AV_CH_LAYOUT_SURROUND },
83  { "3.0(back)", 3, AV_CH_LAYOUT_2_1 },
84  { "4.0", 4, AV_CH_LAYOUT_4POINT0 },
85  { "quad", 4, AV_CH_LAYOUT_QUAD },
86  { "quad(side)", 4, AV_CH_LAYOUT_2_2 },
87  { "3.1", 4, AV_CH_LAYOUT_3POINT1 },
88  { "5.0", 5, AV_CH_LAYOUT_5POINT0_BACK },
89  { "5.0(side)", 5, AV_CH_LAYOUT_5POINT0 },
90  { "4.1", 5, AV_CH_LAYOUT_4POINT1 },
91  { "5.1", 6, AV_CH_LAYOUT_5POINT1_BACK },
92  { "5.1(side)", 6, AV_CH_LAYOUT_5POINT1 },
93  { "6.0", 6, AV_CH_LAYOUT_6POINT0 },
94  { "6.0(front)", 6, AV_CH_LAYOUT_6POINT0_FRONT },
95  { "hexagonal", 6, AV_CH_LAYOUT_HEXAGONAL },
96  { "6.1", 7, AV_CH_LAYOUT_6POINT1 },
97  { "6.1", 7, AV_CH_LAYOUT_6POINT1_BACK },
98  { "6.1(front)", 7, AV_CH_LAYOUT_6POINT1_FRONT },
99  { "7.0", 7, AV_CH_LAYOUT_7POINT0 },
100  { "7.0(front)", 7, AV_CH_LAYOUT_7POINT0_FRONT },
101  { "7.1", 8, AV_CH_LAYOUT_7POINT1 },
102  { "7.1(wide)", 8, AV_CH_LAYOUT_7POINT1_WIDE_BACK },
103  { "7.1(wide-side)", 8, AV_CH_LAYOUT_7POINT1_WIDE },
104  { "octagonal", 8, AV_CH_LAYOUT_OCTAGONAL },
105  { "downmix", 2, AV_CH_LAYOUT_STEREO_DOWNMIX, },
106 };
107 
108 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
109 static uint64_t get_channel_layout_single(const char *name, int name_len, int compat)
110 #else
111 static uint64_t get_channel_layout_single(const char *name, int name_len)
112 #endif
113 {
114  int i;
115  char *end;
116  int64_t layout;
117 
118  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++) {
119  if (strlen(channel_layout_map[i].name) == name_len &&
120  !memcmp(channel_layout_map[i].name, name, name_len))
121  return channel_layout_map[i].layout;
122  }
123  for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
124  if (channel_names[i].name &&
125  strlen(channel_names[i].name) == name_len &&
126  !memcmp(channel_names[i].name, name, name_len))
127  return (int64_t)1 << i;
128  i = strtol(name, &end, 10);
129 
130 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
131  if (compat) {
132  if (end - name == name_len ||
133  (end + 1 - name == name_len && *end == 'c')) {
134  layout = av_get_default_channel_layout(i);
135  if (end - name == name_len) {
136  av_log(NULL, AV_LOG_WARNING,
137  "Single channel layout '%.*s' is interpreted as a number of channels, "
138  "switch to the syntax '%.*sc' otherwise it will be interpreted as a "
139  "channel layout number in a later version\n",
140  name_len, name, name_len, name);
141  return layout;
142  }
143  }
144  } else {
145 #endif
146  if ((end + 1 - name == name_len && *end == 'c'))
147  return av_get_default_channel_layout(i);
148 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
149  }
150 #endif
151 
152  layout = strtoll(name, &end, 0);
153  if (end - name == name_len)
154  return FFMAX(layout, 0);
155  return 0;
156 }
157 
158 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
159 uint64_t ff_get_channel_layout(const char *name, int compat)
160 #else
161 uint64_t av_get_channel_layout(const char *name)
162 #endif
163 {
164  const char *n, *e;
165  const char *name_end = name + strlen(name);
166  int64_t layout = 0, layout_single;
167 
168  for (n = name; n < name_end; n = e + 1) {
169  for (e = n; e < name_end && *e != '+' && *e != '|'; e++);
170 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
171  layout_single = get_channel_layout_single(n, e - n, compat);
172 #else
173  layout_single = get_channel_layout_single(n, e - n);
174 #endif
175  if (!layout_single)
176  return 0;
177  layout |= layout_single;
178  }
179  return layout;
180 }
181 
182 #if FF_API_GET_CHANNEL_LAYOUT_COMPAT
183 uint64_t av_get_channel_layout(const char *name)
184 {
185  return ff_get_channel_layout(name, 1);
186 }
187 #endif
188 
189 void av_bprint_channel_layout(struct AVBPrint *bp,
190  int nb_channels, uint64_t channel_layout)
191 {
192  int i;
193 
194  if (nb_channels <= 0)
195  nb_channels = av_get_channel_layout_nb_channels(channel_layout);
196 
197  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
198  if (nb_channels == channel_layout_map[i].nb_channels &&
199  channel_layout == channel_layout_map[i].layout) {
200  av_bprintf(bp, "%s", channel_layout_map[i].name);
201  return;
202  }
203 
204  av_bprintf(bp, "%d channels", nb_channels);
205  if (channel_layout) {
206  int i, ch;
207  av_bprintf(bp, " (");
208  for (i = 0, ch = 0; i < 64; i++) {
209  if ((channel_layout & (UINT64_C(1) << i))) {
210  const char *name = get_channel_name(i);
211  if (name) {
212  if (ch > 0)
213  av_bprintf(bp, "+");
214  av_bprintf(bp, "%s", name);
215  }
216  ch++;
217  }
218  }
219  av_bprintf(bp, ")");
220  }
221 }
222 
223 void av_get_channel_layout_string(char *buf, int buf_size,
224  int nb_channels, uint64_t channel_layout)
225 {
226  AVBPrint bp;
227 
228  av_bprint_init_for_buffer(&bp, buf, buf_size);
229  av_bprint_channel_layout(&bp, nb_channels, channel_layout);
230 }
231 
232 int av_get_channel_layout_nb_channels(uint64_t channel_layout)
233 {
234  return av_popcount64(channel_layout);
235 }
236 
237 int64_t av_get_default_channel_layout(int nb_channels) {
238  int i;
239  for (i = 0; i < FF_ARRAY_ELEMS(channel_layout_map); i++)
240  if (nb_channels == channel_layout_map[i].nb_channels)
241  return channel_layout_map[i].layout;
242  return 0;
243 }
244 
245 int av_get_channel_layout_channel_index(uint64_t channel_layout,
246  uint64_t channel)
247 {
248  if (!(channel_layout & channel) ||
249  av_get_channel_layout_nb_channels(channel) != 1)
250  return AVERROR(EINVAL);
251  channel_layout &= channel - 1;
252  return av_get_channel_layout_nb_channels(channel_layout);
253 }
254 
255 const char *av_get_channel_name(uint64_t channel)
256 {
257  int i;
258  if (av_get_channel_layout_nb_channels(channel) != 1)
259  return NULL;
260  for (i = 0; i < 64; i++)
261  if ((1ULL<<i) & channel)
262  return get_channel_name(i);
263  return NULL;
264 }
265 
266 const char *av_get_channel_description(uint64_t channel)
267 {
268  int i;
269  if (av_get_channel_layout_nb_channels(channel) != 1)
270  return NULL;
271  for (i = 0; i < FF_ARRAY_ELEMS(channel_names); i++)
272  if ((1ULL<<i) & channel)
273  return channel_names[i].description;
274  return NULL;
275 }
276 
277 uint64_t av_channel_layout_extract_channel(uint64_t channel_layout, int index)
278 {
279  int i;
280 
281  if (av_get_channel_layout_nb_channels(channel_layout) <= index)
282  return 0;
283 
284  for (i = 0; i < 64; i++) {
285  if ((1ULL << i) & channel_layout && !index--)
286  return 1ULL << i;
287  }
288  return 0;
289 }
290 
291 int av_get_standard_channel_layout(unsigned index, uint64_t *layout,
292  const char **name)
293 {
294  if (index >= FF_ARRAY_ELEMS(channel_layout_map))
295  return AVERROR_EOF;
296  if (layout) *layout = channel_layout_map[index].layout;
297  if (name) *name = channel_layout_map[index].name;
298  return 0;
299 }
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