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

   1 #ifndef foochannelmaphfoo
   2 #define foochannelmaphfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of polypaudio.
   8
   9   polypaudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as published
  11   by the Free Software Foundation; either version 2 of the License,
  12   or (at your option) any later version.
  13
  14   polypaudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with polypaudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #include <polyp/sample.h>
  26 #include <polyp/cdecl.h>
  27
  28 /** \page channelmap Channel Maps
  29  *
  30  * \section overv_sec Overview
  31  *
  32  * Channel maps provide a way to associate channels in a stream with a
  33  * specific speaker position. This relieves applications of having to
  34  * make sure their channel order is identical to the final output.
  35  *
  36  * \section init_sec Initialisation
  37  *
  38  * A channel map consists of an array of \ref pa_channel_position values,
  39  * one for each channel. This array is stored together with a channel count
  40  * in a pa_channel_map structure.
  41  *
  42  * Before filling the structure, the application must initialise it using
  43  * pa_channel_map_init(). There are also a number of convenience functions
  44  * for standard channel mappings:
  45  *
  46  * \li pa_channel_map_init_mono() - Create a channel map with only mono audio.
  47  * \li pa_channel_map_init_stereo() - Create a standard stereo mapping.
  48  * \li pa_channel_map_init_auto() - Create a standard channel map for up to
  49  *                                  six channels.
  50  *
  51  * \section conv_sec Convenience Functions
  52  *
  53  * The library contains a number of convenience functions for dealing with
  54  * channel maps:
  55  *
  56  * \li pa_channel_map_valid() - Tests if a channel map is valid.
  57  * \li pa_channel_map_equal() - Tests if two channel maps are identical.
  58  * \li pa_channel_map_snprint() - Creates a textual description of a channel
  59  *                                map.
  60  */
  61
  62 /** \file
  63  * Constants and routines for channel mapping handling */
  64
  65 PA_C_DECL_BEGIN
  66
  67 /** A list of channel labels */
  68 typedef enum pa_channel_position {
  69     PA_CHANNEL_POSITION_INVALID = -1,
  70     PA_CHANNEL_POSITION_MONO = 0,
  71
  72     PA_CHANNEL_POSITION_LEFT,
  73     PA_CHANNEL_POSITION_RIGHT,
  74     PA_CHANNEL_POSITION_CENTER,
  75
  76     PA_CHANNEL_POSITION_FRONT_LEFT = PA_CHANNEL_POSITION_LEFT,
  77     PA_CHANNEL_POSITION_FRONT_RIGHT = PA_CHANNEL_POSITION_RIGHT,
  78     PA_CHANNEL_POSITION_FRONT_CENTER = PA_CHANNEL_POSITION_CENTER,
  79
  80     PA_CHANNEL_POSITION_REAR_CENTER,
  81     PA_CHANNEL_POSITION_REAR_LEFT,
  82     PA_CHANNEL_POSITION_REAR_RIGHT,
  83
  84     PA_CHANNEL_POSITION_LFE,
  85     PA_CHANNEL_POSITION_SUBWOOFER = PA_CHANNEL_POSITION_LFE,
  86
  87     PA_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
  88     PA_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
  89
  90     PA_CHANNEL_POSITION_SIDE_LEFT,
  91     PA_CHANNEL_POSITION_SIDE_RIGHT,
  92
  93     PA_CHANNEL_POSITION_AUX0,
  94     PA_CHANNEL_POSITION_AUX1,
  95     PA_CHANNEL_POSITION_AUX2,
  96     PA_CHANNEL_POSITION_AUX3,
  97     PA_CHANNEL_POSITION_AUX4,
  98     PA_CHANNEL_POSITION_AUX5,
  99     PA_CHANNEL_POSITION_AUX6,
 100     PA_CHANNEL_POSITION_AUX7,
 101     PA_CHANNEL_POSITION_AUX8,
 102     PA_CHANNEL_POSITION_AUX9,
 103     PA_CHANNEL_POSITION_AUX10,
 104     PA_CHANNEL_POSITION_AUX11,
 105     PA_CHANNEL_POSITION_AUX12,
 106     PA_CHANNEL_POSITION_AUX13,
 107     PA_CHANNEL_POSITION_AUX14,
 108     PA_CHANNEL_POSITION_AUX15,
 109     PA_CHANNEL_POSITION_AUX16,
 110     PA_CHANNEL_POSITION_AUX17,
 111     PA_CHANNEL_POSITION_AUX18,
 112     PA_CHANNEL_POSITION_AUX19,
 113     PA_CHANNEL_POSITION_AUX20,
 114     PA_CHANNEL_POSITION_AUX21,
 115     PA_CHANNEL_POSITION_AUX22,
 116     PA_CHANNEL_POSITION_AUX23,
 117     PA_CHANNEL_POSITION_AUX24,
 118     PA_CHANNEL_POSITION_AUX25,
 119     PA_CHANNEL_POSITION_AUX26,
 120     PA_CHANNEL_POSITION_AUX27,
 121     PA_CHANNEL_POSITION_AUX28,
 122     PA_CHANNEL_POSITION_AUX29,
 123     PA_CHANNEL_POSITION_AUX30,
 124     PA_CHANNEL_POSITION_AUX31,
 125
 126     PA_CHANNEL_POSITION_TOP_CENTER,
 127
 128     PA_CHANNEL_POSITION_TOP_FRONT_LEFT,
 129     PA_CHANNEL_POSITION_TOP_FRONT_RIGHT,
 130     PA_CHANNEL_POSITION_TOP_FRONT_CENTER,
 131
 132     PA_CHANNEL_POSITION_TOP_REAR_LEFT,
 133     PA_CHANNEL_POSITION_TOP_REAR_RIGHT,
 134     PA_CHANNEL_POSITION_TOP_REAR_CENTER,
 135
 136     PA_CHANNEL_POSITION_MAX
 137 } pa_channel_position_t;
 138
 139 /** A list of channel mapping definitions for pa_channel_map_init_auto() */
 140 typedef enum pa_channel_map_def {
 141     PA_CHANNEL_MAP_AIFF,   /**< The mapping from RFC3551, which is based on AIFF-C */
 142     PA_CHANNEL_MAP_ALSA,   /**< The default mapping used by ALSA */
 143     PA_CHANNEL_MAP_AUX,    /**< Only aux channels */
 144     PA_CHANNEL_MAP_WAVEEX, /**< Microsoft's WAVEFORMATEXTENSIBLE mapping */
 145     PA_CHANNEL_MAP_OSS,    /**< The default channel mapping used by OSS as defined in the OSS 4.0 API specs */
 146
 147     PA_CHANNEL_MAP_DEFAULT = PA_CHANNEL_MAP_AIFF /**< The default channel map */
 148 } pa_channel_map_def_t;
 149
 150 /** A channel map which can be used to attach labels to specific
 151  * channels of a stream. These values are relevant for conversion and
 152  * mixing of streams */
 153 typedef struct pa_channel_map {
 154     uint8_t channels; /**< Number of channels */
 155     pa_channel_position_t map[PA_CHANNELS_MAX]; /**< Channel labels */
 156 } pa_channel_map;
 157
 158 /** Initialize the specified channel map and return a pointer to it */
 159 pa_channel_map* pa_channel_map_init(pa_channel_map *m);
 160
 161 /** Initialize the specified channel map for monoaural audio and return a pointer to it */
 162 pa_channel_map* pa_channel_map_init_mono(pa_channel_map *m);
 163
 164 /** Initialize the specified channel map for stereophonic audio and return a pointer to it */
 165 pa_channel_map* pa_channel_map_init_stereo(pa_channel_map *m);
 166
 167 /** Initialize the specified channel map for the specified number
 168  * of channels using default labels and return a pointer to it. */
 169 pa_channel_map* pa_channel_map_init_auto(pa_channel_map *m, unsigned channels, pa_channel_map_def_t def);
 170
 171 /** Return a text label for the specified channel position */
 172 const char* pa_channel_position_to_string(pa_channel_position_t pos);
 173
 174 /** The maximum length of strings returned by pa_channel_map_snprint() */
 175 #define PA_CHANNEL_MAP_SNPRINT_MAX 336
 176
 177 /** Make a humand readable string from the specified channel map */
 178 char* pa_channel_map_snprint(char *s, size_t l, const pa_channel_map *map);
 179
 180 /** Parse a channel position list into a channel map structure. \since 0.8.1 */
 181 pa_channel_map *pa_channel_map_parse(pa_channel_map *map, const char *s);
 182
 183 /** Compare two channel maps. Return 1 if both match. */
 184 int pa_channel_map_equal(const pa_channel_map *a, const pa_channel_map *b);
 185
 186 /** Return non-zero of the specified channel map is considered valid */
 187 int pa_channel_map_valid(const pa_channel_map *map);
 188
 189 PA_C_DECL_END
 190
 191 #endif