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

   1 #ifndef foosamplehfoo
   2 #define foosamplehfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of PulseAudio.
   8
   9   Copyright 2004-2006 Lennart Poettering
  10   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
  11
  12   PulseAudio is free software; you can redistribute it and/or modify
  13   it under the terms of the GNU Lesser General Public License as published
  14   by the Free Software Foundation; either version 2 of the License,
  15   or (at your option) any later version.
  16
  17   PulseAudio is distributed in the hope that it will be useful, but
  18   WITHOUT ANY WARRANTY; without even the implied warranty of
  19   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  20   General Public License for more details.
  21
  22   You should have received a copy of the GNU Lesser General Public License
  23   along with PulseAudio; if not, write to the Free Software
  24   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  25   USA.
  26 ***/
  27
  28 #include <inttypes.h>
  29 #include <sys/types.h>
  30 #include <sys/param.h>
  31 #include <math.h>
  32
  33 #include <pulse/cdecl.h>
  34
  35 /** \page sample Sample Format Specifications
  36  *
  37  * \section overv_sec Overview
  38  *
  39  * PulseAudio is capable of handling a multitude of sample formats, rates
  40  * and channels, transparently converting and mixing them as needed.
  41  *
  42  * \section format_sec Sample Format
  43  *
  44  * PulseAudio supports the following sample formats:
  45  *
  46  * \li PA_SAMPLE_U8 - Unsigned 8 bit integer PCM.
  47  * \li PA_SAMPLE_S16LE - Signed 16 integer bit PCM, little endian.
  48  * \li PA_SAMPLE_S16BE - Signed 16 integer bit PCM, big endian.
  49  * \li PA_SAMPLE_FLOAT32LE - 32 bit IEEE floating point PCM, little endian.
  50  * \li PA_SAMPLE_FLOAT32BE - 32 bit IEEE floating point PCM, big endian.
  51  * \li PA_SAMPLE_ALAW - 8 bit a-Law.
  52  * \li PA_SAMPLE_ULAW - 8 bit mu-Law.
  53  * \li PA_SAMPLE_S32LE - Signed 32 bit integer PCM, little endian.
  54  * \li PA_SAMPLE_S32BE - Signed 32 bit integer PCM, big endian.
  55  *
  56  * The floating point sample formats have the range from -1 to 1.
  57  *
  58  * The sample formats that are sensitive to endianness have convenience
  59  * macros for native endian (NE), and reverse endian (RE).
  60  *
  61  * \section rate_sec Sample Rates
  62  *
  63  * PulseAudio supports any sample rate between 1 Hz and 4 GHz. There is no
  64  * point trying to exceed the sample rate of the output device though as the
  65  * signal will only get downsampled, consuming CPU on the machine running the
  66  * server.
  67  *
  68  * \section chan_sec Channels
  69  *
  70  * PulseAudio supports up to 16 individiual channels. The order of the
  71  * channels is up to the application, but they must be continous. To map
  72  * channels to speakers, see \ref channelmap.
  73  *
  74  * \section calc_sec Calculations
  75  *
  76  * The PulseAudio library contains a number of convenience functions to do
  77  * calculations on sample formats:
  78  *
  79  * \li pa_bytes_per_second() - The number of bytes one second of audio will
  80  *                             take given a sample format.
  81  * \li pa_frame_size() - The size, in bytes, of one frame (i.e. one set of
  82  *                       samples, one for each channel).
  83  * \li pa_sample_size() - The size, in bytes, of one sample.
  84  * \li pa_bytes_to_usec() - Calculate the time it would take to play a buffer
  85  *                          of a certain size.
  86  *
  87  * \section util_sec Convenience Functions
  88  *
  89  * The library also contains a couple of other convenience functions:
  90  *
  91  * \li pa_sample_spec_valid() - Tests if a sample format specification is
  92  *                              valid.
  93  * \li pa_sample_spec_equal() - Tests if the sample format specifications are
  94  *                              identical.
  95  * \li pa_sample_format_to_string() - Return a textual description of a
  96  *                                    sample format.
  97  * \li pa_parse_sample_format() - Parse a text string into a sample format.
  98  * \li pa_sample_spec_snprint() - Create a textual description of a complete
  99  *                                 sample format specification.
 100  * \li pa_bytes_snprint() - Pretty print a byte value (e.g. 2.5 MiB).
 101  */
 102
 103 /** \file
 104  * Constants and routines for sample type handling */
 105
 106 PA_C_DECL_BEGIN
 107
 108 #if !defined(WORDS_BIGENDIAN)
 109 #if defined(__BYTE_ORDER)
 110 #if __BYTE_ORDER == __BIG_ENDIAN
 111 #define WORDS_BIGENDIAN
 112 #endif
 113 #endif
 114 #endif
 115
 116 /** Maximum number of allowed channels */
 117 #define PA_CHANNELS_MAX 32
 118
 119 /** Maximum allowed sample rate */
 120 #define PA_RATE_MAX (48000*4)
 121
 122 /** Sample format */
 123 typedef enum pa_sample_format {
 124     PA_SAMPLE_U8,              /**< Unsigned 8 Bit PCM */
 125     PA_SAMPLE_ALAW,            /**< 8 Bit a-Law */
 126     PA_SAMPLE_ULAW,            /**< 8 Bit mu-Law */
 127     PA_SAMPLE_S16LE,           /**< Signed 16 Bit PCM, little endian (PC) */
 128     PA_SAMPLE_S16BE,           /**< Signed 16 Bit PCM, big endian */
 129     PA_SAMPLE_FLOAT32LE,       /**< 32 Bit IEEE floating point, little endian, range -1 to 1 */
 130     PA_SAMPLE_FLOAT32BE,       /**< 32 Bit IEEE floating point, big endian, range -1 to 1 */
 131     PA_SAMPLE_S32LE,           /**< Signed 32 Bit PCM, little endian (PC) */
 132     PA_SAMPLE_S32BE,           /**< Signed 32 Bit PCM, big endian (PC) */
 133     PA_SAMPLE_MAX,             /**< Upper limit of valid sample types */
 134     PA_SAMPLE_INVALID = -1     /**< An invalid value */
 135 } pa_sample_format_t;
 136
 137 #ifdef WORDS_BIGENDIAN
 138 /** Signed 16 Bit PCM, native endian */
 139 #define PA_SAMPLE_S16NE PA_SAMPLE_S16BE
 140 /** 32 Bit IEEE floating point, native endian */
 141 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32BE
 142 /** Signed 32 Bit PCM, native endian */
 143 #define PA_SAMPLE_S32NE PA_SAMPLE_S32BE
 144 /** Signed 16 Bit PCM reverse endian */
 145 #define PA_SAMPLE_S16RE PA_SAMPLE_S16LE
 146 /** 32 Bit IEEE floating point, reverse endian */
 147 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32LE
 148 /** Signed 32 Bit PCM reverse endian */
 149 #define PA_SAMPLE_S32RE PA_SAMPLE_S32LE
 150 #else
 151 /** Signed 16 Bit PCM, native endian */
 152 #define PA_SAMPLE_S16NE PA_SAMPLE_S16LE
 153 /** 32 Bit IEEE floating point, native endian */
 154 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32LE
 155 /** Signed 32 Bit PCM, native endian */
 156 #define PA_SAMPLE_S32NE PA_SAMPLE_S32LE
 157 /** Signed 16 Bit PCM reverse endian */
 158 #define PA_SAMPLE_S16RE PA_SAMPLE_S16BE
 159 /** 32 Bit IEEE floating point, reverse endian */
 160 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32BE
 161 /** Signed 32 Bit PCM reverse endian */
 162 #define PA_SAMPLE_S32RE PA_SAMPLE_S32BE
 163 #endif
 164
 165 /** A Shortcut for PA_SAMPLE_FLOAT32NE */
 166 #define PA_SAMPLE_FLOAT32 PA_SAMPLE_FLOAT32NE
 167
 168 /** A sample format and attribute specification */
 169 typedef struct pa_sample_spec {
 170     pa_sample_format_t format;     /**< The sample format */
 171     uint32_t rate;                 /**< The sample rate. (e.g. 44100) */
 172     uint8_t channels;              /**< Audio channels. (1 for mono, 2 for stereo, ...) */
 173 } pa_sample_spec;
 174
 175 /** Type for usec specifications (unsigned). May be either 32 or 64 bit, depending on the architecture */
 176 typedef uint64_t pa_usec_t;
 177
 178 /** Return the amount of bytes playback of a second of audio with the specified sample type takes */
 179 size_t pa_bytes_per_second(const pa_sample_spec *spec) PA_GCC_PURE;
 180
 181 /** Return the size of a frame with the specific sample type */
 182 size_t pa_frame_size(const pa_sample_spec *spec) PA_GCC_PURE;
 183
 184 /** Return the size of a sample with the specific sample type */
 185 size_t pa_sample_size(const pa_sample_spec *spec) PA_GCC_PURE;
 186
 187 /** Calculate the time the specified bytes take to play with the specified sample type */
 188 pa_usec_t pa_bytes_to_usec(uint64_t length, const pa_sample_spec *spec) PA_GCC_PURE;
 189
 190 /** Calculates the number of bytes that are required for the specified time. \since 0.9 */
 191 size_t pa_usec_to_bytes(pa_usec_t t, const pa_sample_spec *spec) PA_GCC_PURE;
 192
 193 /** Return non-zero when the sample type specification is valid */
 194 int pa_sample_spec_valid(const pa_sample_spec *spec) PA_GCC_PURE;
 195
 196 /** Return non-zero when the two sample type specifications match */
 197 int pa_sample_spec_equal(const pa_sample_spec*a, const pa_sample_spec*b) PA_GCC_PURE;
 198
 199 /** Return a descriptive string for the specified sample format. \since 0.8 */
 200 const char *pa_sample_format_to_string(pa_sample_format_t f) PA_GCC_PURE;
 201
 202 /** Parse a sample format text. Inverse of pa_sample_format_to_string() */
 203 pa_sample_format_t pa_parse_sample_format(const char *format) PA_GCC_PURE;
 204
 205 /** Maximum required string length for pa_sample_spec_snprint() */
 206 #define PA_SAMPLE_SPEC_SNPRINT_MAX 32
 207
 208 /** Pretty print a sample type specification to a string */
 209 char* pa_sample_spec_snprint(char *s, size_t l, const pa_sample_spec *spec);
 210
 211 /** Pretty print a byte size value. (i.e. "2.5 MiB") */
 212 char* pa_bytes_snprint(char *s, size_t l, unsigned v);
 213
 214 PA_C_DECL_END
 215
 216 #endif