code.delx.au - pulseaudio/blob - src/pulse/channelmap.h

   1 #ifndef foochannelmaphfoo
   2 #define foochannelmaphfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2005-2006 Lennart Poettering
   8   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   9
  10   PulseAudio is free software; you can redistribute it and/or modify
  11   it under the terms of the GNU Lesser General Public License as published
  12   by the Free Software Foundation; either version 2 of the License,
  13   or (at your option) any later version.
  14
  15   PulseAudio is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with PulseAudio; if not, write to the Free Software
  22   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  23   USA.
  24 ***/
  25
  26 #include <pulse/sample.h>
  27 #include <pulse/cdecl.h>
  28 #include <pulse/gccmacro.h>
  29
  30 /** \page channelmap Channel Maps
  31  *
  32  * \section overv_sec Overview
  33  *
  34  * Channel maps provide a way to associate channels in a stream with a
  35  * specific speaker position. This relieves applications of having to
  36  * make sure their channel order is identical to the final output.
  37  *
  38  * \section init_sec Initialisation
  39  *
  40  * A channel map consists of an array of \ref pa_channel_position values,
  41  * one for each channel. This array is stored together with a channel count
  42  * in a pa_channel_map structure.
  43  *
  44  * Before filling the structure, the application must initialise it using
  45  * pa_channel_map_init(). There are also a number of convenience functions
  46  * for standard channel mappings:
  47  *
  48  * \li pa_channel_map_init_mono() - Create a channel map with only mono audio.
  49  * \li pa_channel_map_init_stereo() - Create a standard stereo mapping.
  50  * \li pa_channel_map_init_auto() - Create a standard channel map for a specific number of channels
  51  * \li pa_channel_map_init_extend() - Similar to
  52  * pa_channel_map_init_auto() but synthesize a channel map if noone
  53  * predefined one is known for the specified number of channels.
  54  *
  55  * \section conv_sec Convenience Functions
  56  *
  57  * The library contains a number of convenience functions for dealing with
  58  * channel maps:
  59  *
  60  * \li pa_channel_map_valid() - Tests if a channel map is valid.
  61  * \li pa_channel_map_equal() - Tests if two channel maps are identical.
  62  * \li pa_channel_map_snprint() - Creates a textual description of a channel
  63  *                                map.
  64  */
  65
  66 /** \file
  67  * Constants and routines for channel mapping handling */
  68
  69 PA_C_DECL_BEGIN
  70
  71 /** A list of channel labels */
  72 typedef enum pa_channel_position {
  73     PA_CHANNEL_POSITION_INVALID = -1,
  74     PA_CHANNEL_POSITION_MONO = 0,
  75
  76     PA_CHANNEL_POSITION_LEFT,
  77     PA_CHANNEL_POSITION_RIGHT,
  78     PA_CHANNEL_POSITION_CENTER,
  79
  80     PA_CHANNEL_POSITION_FRONT_LEFT = PA_CHANNEL_POSITION_LEFT,
  81     PA_CHANNEL_POSITION_FRONT_RIGHT = PA_CHANNEL_POSITION_RIGHT,
  82     PA_CHANNEL_POSITION_FRONT_CENTER = PA_CHANNEL_POSITION_CENTER,
  83
  84     PA_CHANNEL_POSITION_REAR_CENTER,
  85     PA_CHANNEL_POSITION_REAR_LEFT,
  86     PA_CHANNEL_POSITION_REAR_RIGHT,
  87
  88     PA_CHANNEL_POSITION_LFE,
  89     PA_CHANNEL_POSITION_SUBWOOFER = PA_CHANNEL_POSITION_LFE,
  90
  91     PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
  92     PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
  93
  94     PA_CHANNEL_POSITION_SIDE_LEFT,
  95     PA_CHANNEL_POSITION_SIDE_RIGHT,
  96
  97     PA_CHANNEL_POSITION_AUX0,
  98     PA_CHANNEL_POSITION_AUX1,
  99     PA_CHANNEL_POSITION_AUX2,
 100     PA_CHANNEL_POSITION_AUX3,
 101     PA_CHANNEL_POSITION_AUX4,
 102     PA_CHANNEL_POSITION_AUX5,
 103     PA_CHANNEL_POSITION_AUX6,
 104     PA_CHANNEL_POSITION_AUX7,
 105     PA_CHANNEL_POSITION_AUX8,
 106     PA_CHANNEL_POSITION_AUX9,
 107     PA_CHANNEL_POSITION_AUX10,
 108     PA_CHANNEL_POSITION_AUX11,
 109     PA_CHANNEL_POSITION_AUX12,
 110     PA_CHANNEL_POSITION_AUX13,
 111     PA_CHANNEL_POSITION_AUX14,
 112     PA_CHANNEL_POSITION_AUX15,
 113     PA_CHANNEL_POSITION_AUX16,
 114     PA_CHANNEL_POSITION_AUX17,
 115     PA_CHANNEL_POSITION_AUX18,
 116     PA_CHANNEL_POSITION_AUX19,
 117     PA_CHANNEL_POSITION_AUX20,
 118     PA_CHANNEL_POSITION_AUX21,
 119     PA_CHANNEL_POSITION_AUX22,
 120     PA_CHANNEL_POSITION_AUX23,
 121     PA_CHANNEL_POSITION_AUX24,
 122     PA_CHANNEL_POSITION_AUX25,
 123     PA_CHANNEL_POSITION_AUX26,
 124     PA_CHANNEL_POSITION_AUX27,
 125     PA_CHANNEL_POSITION_AUX28,
 126     PA_CHANNEL_POSITION_AUX29,
 127     PA_CHANNEL_POSITION_AUX30,
 128     PA_CHANNEL_POSITION_AUX31,
 129
 130     PA_CHANNEL_POSITION_TOP_CENTER,
 131
 132     PA_CHANNEL_POSITION_TOP_FRONT_LEFT,
 133     PA_CHANNEL_POSITION_TOP_FRONT_RIGHT,
 134     PA_CHANNEL_POSITION_TOP_FRONT_CENTER,
 135
 136     PA_CHANNEL_POSITION_TOP_REAR_LEFT,
 137     PA_CHANNEL_POSITION_TOP_REAR_RIGHT,
 138     PA_CHANNEL_POSITION_TOP_REAR_CENTER,
 139
 140     PA_CHANNEL_POSITION_MAX
 141 } pa_channel_position_t;
 142
 143 /** A list of channel mapping definitions for pa_channel_map_init_auto() */
 144 typedef enum pa_channel_map_def {
 145     PA_CHANNEL_MAP_AIFF,
 146     /**< The mapping from RFC3551, which is based on AIFF-C */
 147
 148     PA_CHANNEL_MAP_ALSA,
 149     /**< The default mapping used by ALSA */
 150
 151     PA_CHANNEL_MAP_AUX,
 152     /**< Only aux channels */
 153
 154     PA_CHANNEL_MAP_WAVEEX,
 155     /**< Microsoft's WAVEFORMATEXTENSIBLE mapping */
 156
 157     PA_CHANNEL_MAP_OSS,
 158     /**< The default channel mapping used by OSS as defined in the OSS 4.0 API specs */
 159
 160     /**< Upper limit of valid channel mapping definitions */
 161     PA_CHANNEL_MAP_DEF_MAX,
 162
 163     PA_CHANNEL_MAP_DEFAULT = PA_CHANNEL_MAP_AIFF
 164     /**< The default channel map */
 165 } pa_channel_map_def_t;
 166
 167 /** A channel map which can be used to attach labels to specific
 168  * channels of a stream. These values are relevant for conversion and
 169  * mixing of streams */
 170 typedef struct pa_channel_map {
 171     uint8_t channels;
 172     /**< Number of channels */
 173
 174     pa_channel_position_t map[PA_CHANNELS_MAX];
 175     /**< Channel labels */
 176 } pa_channel_map;
 177
 178 /** Initialize the specified channel map and return a pointer to it */
 179 pa_channel_map* pa_channel_map_init(pa_channel_map *m);
 180
 181 /** Initialize the specified channel map for monoaural audio and return a pointer to it */
 182 pa_channel_map* pa_channel_map_init_mono(pa_channel_map *m);
 183
 184 /** Initialize the specified channel map for stereophonic audio and return a pointer to it */
 185 pa_channel_map* pa_channel_map_init_stereo(pa_channel_map *m);
 186
 187 /** Initialize the specified channel map for the specified number of
 188  * channels using default labels and return a pointer to it. This call
 189  * will fail (return NULL) if there is no default channel map known for this
 190  * specific number of channels and mapping. */
 191 pa_channel_map* pa_channel_map_init_auto(pa_channel_map *m, unsigned channels, pa_channel_map_def_t def);
 192
 193 /** Similar to pa_channel_map_init_auto() but instead of failing if no
 194  * default mapping is known with the specified parameters it will
 195  * synthesize a mapping based on a known mapping with fewer channels
 196  * and fill up the rest with AUX0...AUX31 channels  \since 0.9.11 */
 197 pa_channel_map* pa_channel_map_init_extend(pa_channel_map *m, unsigned channels, pa_channel_map_def_t def);
 198
 199 /** Return a text label for the specified channel position */
 200 const char* pa_channel_position_to_string(pa_channel_position_t pos) PA_GCC_PURE;
 201
 202 /** Return a human readable text label for the specified channel position. \since 0.9.7 */
 203 const char* pa_channel_position_to_pretty_string(pa_channel_position_t pos);
 204
 205 /** The maximum length of strings returned by pa_channel_map_snprint() */
 206 #define PA_CHANNEL_MAP_SNPRINT_MAX 336
 207
 208 /** Make a humand readable string from the specified channel map */
 209 char* pa_channel_map_snprint(char *s, size_t l, const pa_channel_map *map);
 210
 211 /** Parse a channel position list into a channel map structure. */
 212 pa_channel_map *pa_channel_map_parse(pa_channel_map *map, const char *s);
 213
 214 /** Compare two channel maps. Return 1 if both match. */
 215 int pa_channel_map_equal(const pa_channel_map *a, const pa_channel_map *b) PA_GCC_PURE;
 216
 217 /** Return non-zero if the specified channel map is considered valid */
 218 int pa_channel_map_valid(const pa_channel_map *map) PA_GCC_PURE;
 219
 220 /** Return non-zero if the specified channel map is compatible with
 221  * the specified sample spec. \since 0.9.12 */
 222 int pa_channel_map_compatible(const pa_channel_map *map, const pa_sample_spec *ss) PA_GCC_PURE;
 223
 224 PA_C_DECL_END
 225
 226 #endif