1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
#ifndef foochannelmaphfoo
#define foochannelmaphfoo
/***
This file is part of PulseAudio.
Copyright 2005-2006 Lennart Poettering
Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#include <pulse/sample.h>
#include <pulse/cdecl.h>
#include <pulse/gccmacro.h>
/** \page channelmap Channel Maps
*
* \section overv_sec Overview
*
* Channel maps provide a way to associate channels in a stream with a
* specific speaker position. This relieves applications of having to
* make sure their channel order is identical to the final output.
*
* \section init_sec Initialisation
*
* A channel map consists of an array of \ref pa_channel_position values,
* one for each channel. This array is stored together with a channel count
* in a pa_channel_map structure.
*
* Before filling the structure, the application must initialise it using
* pa_channel_map_init(). There are also a number of convenience functions
* for standard channel mappings:
*
* \li pa_channel_map_init_mono() - Create a channel map with only mono audio.
* \li pa_channel_map_init_stereo() - Create a standard stereo mapping.
* \li pa_channel_map_init_auto() - Create a standard channel map for up to
* six channels.
*
* \section conv_sec Convenience Functions
*
* The library contains a number of convenience functions for dealing with
* channel maps:
*
* \li pa_channel_map_valid() - Tests if a channel map is valid.
* \li pa_channel_map_equal() - Tests if two channel maps are identical.
* \li pa_channel_map_snprint() - Creates a textual description of a channel
* map.
*/
/** \file
* Constants and routines for channel mapping handling */
PA_C_DECL_BEGIN
/** A list of channel labels */
typedef enum pa_channel_position {
PA_CHANNEL_POSITION_INVALID = -1,
PA_CHANNEL_POSITION_MONO = 0,
PA_CHANNEL_POSITION_LEFT,
PA_CHANNEL_POSITION_RIGHT,
PA_CHANNEL_POSITION_CENTER,
PA_CHANNEL_POSITION_FRONT_LEFT = PA_CHANNEL_POSITION_LEFT,
PA_CHANNEL_POSITION_FRONT_RIGHT = PA_CHANNEL_POSITION_RIGHT,
PA_CHANNEL_POSITION_FRONT_CENTER = PA_CHANNEL_POSITION_CENTER,
PA_CHANNEL_POSITION_REAR_CENTER,
PA_CHANNEL_POSITION_REAR_LEFT,
PA_CHANNEL_POSITION_REAR_RIGHT,
PA_CHANNEL_POSITION_LFE,
PA_CHANNEL_POSITION_SUBWOOFER = PA_CHANNEL_POSITION_LFE,
PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
PA_CHANNEL_POSITION_SIDE_LEFT,
PA_CHANNEL_POSITION_SIDE_RIGHT,
PA_CHANNEL_POSITION_AUX0,
PA_CHANNEL_POSITION_AUX1,
PA_CHANNEL_POSITION_AUX2,
PA_CHANNEL_POSITION_AUX3,
PA_CHANNEL_POSITION_AUX4,
PA_CHANNEL_POSITION_AUX5,
PA_CHANNEL_POSITION_AUX6,
PA_CHANNEL_POSITION_AUX7,
PA_CHANNEL_POSITION_AUX8,
PA_CHANNEL_POSITION_AUX9,
PA_CHANNEL_POSITION_AUX10,
PA_CHANNEL_POSITION_AUX11,
PA_CHANNEL_POSITION_AUX12,
PA_CHANNEL_POSITION_AUX13,
PA_CHANNEL_POSITION_AUX14,
PA_CHANNEL_POSITION_AUX15,
PA_CHANNEL_POSITION_AUX16,
PA_CHANNEL_POSITION_AUX17,
PA_CHANNEL_POSITION_AUX18,
PA_CHANNEL_POSITION_AUX19,
PA_CHANNEL_POSITION_AUX20,
PA_CHANNEL_POSITION_AUX21,
PA_CHANNEL_POSITION_AUX22,
PA_CHANNEL_POSITION_AUX23,
PA_CHANNEL_POSITION_AUX24,
PA_CHANNEL_POSITION_AUX25,
PA_CHANNEL_POSITION_AUX26,
PA_CHANNEL_POSITION_AUX27,
PA_CHANNEL_POSITION_AUX28,
PA_CHANNEL_POSITION_AUX29,
PA_CHANNEL_POSITION_AUX30,
PA_CHANNEL_POSITION_AUX31,
PA_CHANNEL_POSITION_TOP_CENTER,
PA_CHANNEL_POSITION_TOP_FRONT_LEFT,
PA_CHANNEL_POSITION_TOP_FRONT_RIGHT,
PA_CHANNEL_POSITION_TOP_FRONT_CENTER,
PA_CHANNEL_POSITION_TOP_REAR_LEFT,
PA_CHANNEL_POSITION_TOP_REAR_RIGHT,
PA_CHANNEL_POSITION_TOP_REAR_CENTER,
PA_CHANNEL_POSITION_MAX
} pa_channel_position_t;
/** A list of channel mapping definitions for pa_channel_map_init_auto() */
typedef enum pa_channel_map_def {
PA_CHANNEL_MAP_AIFF, /**< The mapping from RFC3551, which is based on AIFF-C */
PA_CHANNEL_MAP_ALSA, /**< The default mapping used by ALSA */
PA_CHANNEL_MAP_AUX, /**< Only aux channels */
PA_CHANNEL_MAP_WAVEEX, /**< Microsoft's WAVEFORMATEXTENSIBLE mapping */
PA_CHANNEL_MAP_OSS, /**< The default channel mapping used by OSS as defined in the OSS 4.0 API specs */
PA_CHANNEL_MAP_DEFAULT = PA_CHANNEL_MAP_AIFF /**< The default channel map */
} pa_channel_map_def_t;
/** A channel map which can be used to attach labels to specific
* channels of a stream. These values are relevant for conversion and
* mixing of streams */
typedef struct pa_channel_map {
uint8_t channels; /**< Number of channels */
pa_channel_position_t map[PA_CHANNELS_MAX]; /**< Channel labels */
} pa_channel_map;
/** Initialize the specified channel map and return a pointer to it */
pa_channel_map* pa_channel_map_init(pa_channel_map *m);
/** Initialize the specified channel map for monoaural audio and return a pointer to it */
pa_channel_map* pa_channel_map_init_mono(pa_channel_map *m);
/** Initialize the specified channel map for stereophonic audio and return a pointer to it */
pa_channel_map* pa_channel_map_init_stereo(pa_channel_map *m);
/** Initialize the specified channel map for the specified number of
* channels using default labels and return a pointer to it. This call
* will fail (return NULL) if there is no default channel map known for this
* specific number of channels and mapping. */
pa_channel_map* pa_channel_map_init_auto(pa_channel_map *m, unsigned channels, pa_channel_map_def_t def);
/** Similar to pa_channel_map_init_auto() but instead of failing if no
* default mapping is known with the specified parameters it will
* synthesize a mapping based on a known mapping with fewer channels
* and fill up the rest with AUX0...AUX31 channels \since 0.9.11 */
pa_channel_map* pa_channel_map_init_extend(pa_channel_map *m, unsigned channels, pa_channel_map_def_t def);
/** Return a text label for the specified channel position */
const char* pa_channel_position_to_string(pa_channel_position_t pos) PA_GCC_PURE;
/** Return a human readable text label for the specified channel position. \since 0.9.7 */
const char* pa_channel_position_to_pretty_string(pa_channel_position_t pos);
/** The maximum length of strings returned by pa_channel_map_snprint() */
#define PA_CHANNEL_MAP_SNPRINT_MAX 336
/** Make a humand readable string from the specified channel map */
char* pa_channel_map_snprint(char *s, size_t l, const pa_channel_map *map);
/** Parse a channel position list into a channel map structure. */
pa_channel_map *pa_channel_map_parse(pa_channel_map *map, const char *s);
/** Compare two channel maps. Return 1 if both match. */
int pa_channel_map_equal(const pa_channel_map *a, const pa_channel_map *b) PA_GCC_PURE;
/** Return non-zero of the specified channel map is considered valid */
int pa_channel_map_valid(const pa_channel_map *map) PA_GCC_PURE;
PA_C_DECL_END
#endif
|
