2 * Copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
4 * This file is part of Libav.
6 * Libav 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.
11 * Libav 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.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with Libav; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 * audio conversion routines
28 #include "audioconvert.h"
30 static const char * const channel_names[] = {
31 [0] = "FL", /* front left */
32 [1] = "FR", /* front right */
33 [2] = "FC", /* front center */
34 [3] = "LFE", /* low frequency */
35 [4] = "BL", /* back left */
36 [5] = "BR", /* back right */
37 [6] = "FLC", /* front left-of-center */
38 [7] = "FRC", /* front right-of-center */
39 [8] = "BC", /* back-center */
40 [9] = "SL", /* side left */
41 [10] = "SR", /* side right */
42 [11] = "TC", /* top center */
43 [12] = "TFL", /* top front left */
44 [13] = "TFC", /* top front center */
45 [14] = "TFR", /* top front right */
46 [15] = "TBL", /* top back left */
47 [16] = "TBC", /* top back center */
48 [17] = "TBR", /* top back right */
49 [29] = "DL", /* downmix left */
50 [30] = "DR", /* downmix right */
53 static const char *get_channel_name(int channel_id)
55 if (channel_id < 0 || channel_id >= FF_ARRAY_ELEMS(channel_names))
57 return channel_names[channel_id];
64 } channel_layout_map[] = {
65 { "mono", 1, AV_CH_LAYOUT_MONO },
66 { "stereo", 2, AV_CH_LAYOUT_STEREO },
67 { "4.0", 4, AV_CH_LAYOUT_4POINT0 },
68 { "quad", 4, AV_CH_LAYOUT_QUAD },
69 { "5.0", 5, AV_CH_LAYOUT_5POINT0 },
70 { "5.0", 5, AV_CH_LAYOUT_5POINT0_BACK },
71 { "5.1", 6, AV_CH_LAYOUT_5POINT1 },
72 { "5.1", 6, AV_CH_LAYOUT_5POINT1_BACK },
73 { "5.1+downmix", 8, AV_CH_LAYOUT_5POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
74 { "7.1", 8, AV_CH_LAYOUT_7POINT1 },
75 { "7.1(wide)", 8, AV_CH_LAYOUT_7POINT1_WIDE },
76 { "7.1+downmix", 10, AV_CH_LAYOUT_7POINT1|AV_CH_LAYOUT_STEREO_DOWNMIX, },
80 uint64_t av_get_channel_layout(const char *name)
84 if (!strcmp(channel_layout_map[i].name, name))
85 return channel_layout_map[i].layout;
87 } while (channel_layout_map[i].name);
92 void av_get_channel_layout_string(char *buf, int buf_size,
93 int nb_channels, uint64_t channel_layout)
98 nb_channels = av_get_channel_layout_nb_channels(channel_layout);
100 for (i = 0; channel_layout_map[i].name; i++)
101 if (nb_channels == channel_layout_map[i].nb_channels &&
102 channel_layout == channel_layout_map[i].layout) {
103 av_strlcpy(buf, channel_layout_map[i].name, buf_size);
107 snprintf(buf, buf_size, "%d channels", nb_channels);
108 if (channel_layout) {
110 av_strlcat(buf, " (", buf_size);
111 for (i = 0, ch = 0; i < 64; i++) {
112 if ((channel_layout & (UINT64_C(1) << i))) {
113 const char *name = get_channel_name(i);
116 av_strlcat(buf, "|", buf_size);
117 av_strlcat(buf, name, buf_size);
122 av_strlcat(buf, ")", buf_size);
126 int av_get_channel_layout_nb_channels(uint64_t channel_layout)
129 uint64_t x = channel_layout;
130 for (count = 0; x; count++)
131 x &= x-1; // unset lowest set bit