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

   1 #ifndef foosamplehfoo
   2 #define foosamplehfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2004-2006 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 <inttypes.h>
  27 #include <sys/types.h>
  28 #include <sys/param.h>
  29 #include <math.h>
  30
  31 #include <pulse/gccmacro.h>
  32 #include <pulse/cdecl.h>
  33
  34 /** \page sample Sample Format Specifications
  35  *
  36  * \section overv_sec Overview
  37  *
  38  * PulseAudio is capable of handling a multitude of sample formats, rates
  39  * and channels, transparently converting and mixing them as needed.
  40  *
  41  * \section format_sec Sample Format
  42  *
  43  * PulseAudio supports the following sample formats:
  44  *
  45  * \li PA_SAMPLE_U8 - Unsigned 8 bit integer PCM.
  46  * \li PA_SAMPLE_S16LE - Signed 16 integer bit PCM, little endian.
  47  * \li PA_SAMPLE_S16BE - Signed 16 integer bit PCM, big endian.
  48  * \li PA_SAMPLE_FLOAT32LE - 32 bit IEEE floating point PCM, little endian.
  49  * \li PA_SAMPLE_FLOAT32BE - 32 bit IEEE floating point PCM, big endian.
  50  * \li PA_SAMPLE_ALAW - 8 bit a-Law.
  51  * \li PA_SAMPLE_ULAW - 8 bit mu-Law.
  52  * \li PA_SAMPLE_S32LE - Signed 32 bit integer PCM, little endian.
  53  * \li PA_SAMPLE_S32BE - Signed 32 bit integer PCM, big endian.
  54  *
  55  * The floating point sample formats have the range from -1.0 to 1.0.
  56  *
  57  * The sample formats that are sensitive to endianness have convenience
  58  * macros for native endian (NE), and reverse endian (RE).
  59  *
  60  * \section rate_sec Sample Rates
  61  *
  62  * PulseAudio supports any sample rate between 1 Hz and 4 GHz. There is no
  63  * point trying to exceed the sample rate of the output device though as the
  64  * signal will only get downsampled, consuming CPU on the machine running the
  65  * server.
  66  *
  67  * \section chan_sec Channels
  68  *
  69  * PulseAudio supports up to 16 individiual channels. The order of the
  70  * channels is up to the application, but they must be continous. To map
  71  * channels to speakers, see \ref channelmap.
  72  *
  73  * \section calc_sec Calculations
  74  *
  75  * The PulseAudio library contains a number of convenience functions to do
  76  * calculations on sample formats:
  77  *
  78  * \li pa_bytes_per_second() - The number of bytes one second of audio will
  79  *                             take given a sample format.
  80  * \li pa_frame_size() - The size, in bytes, of one frame (i.e. one set of
  81  *                       samples, one for each channel).
  82  * \li pa_sample_size() - The size, in bytes, of one sample.
  83  * \li pa_bytes_to_usec() - Calculate the time it would take to play a buffer
  84  *                          of a certain size.
  85  *
  86  * \section util_sec Convenience Functions
  87  *
  88  * The library also contains a couple of other convenience functions:
  89  *
  90  * \li pa_sample_spec_valid() - Tests if a sample format specification is
  91  *                              valid.
  92  * \li pa_sample_spec_equal() - Tests if the sample format specifications are
  93  *                              identical.
  94  * \li pa_sample_format_to_string() - Return a textual description of a
  95  *                                    sample format.
  96  * \li pa_parse_sample_format() - Parse a text string into a sample format.
  97  * \li pa_sample_spec_snprint() - Create a textual description of a complete
  98  *                                 sample format specification.
  99  * \li pa_bytes_snprint() - Pretty print a byte value (e.g. 2.5 MiB).
 100  */
 101
 102 /** \file
 103  * Constants and routines for sample type handling */
 104
 105 PA_C_DECL_BEGIN
 106
 107 #if !defined(WORDS_BIGENDIAN)
 108 #if defined(__BYTE_ORDER)
 109 #if __BYTE_ORDER == __BIG_ENDIAN
 110 #define WORDS_BIGENDIAN
 111 #endif
 112 #endif
 113 #endif
 114
 115 /** Maximum number of allowed channels */
 116 #define PA_CHANNELS_MAX 32U
 117
 118 /** Maximum allowed sample rate */
 119 #define PA_RATE_MAX (48000U*4U)
 120
 121 /** Sample format */
 122 typedef enum pa_sample_format {
 123     PA_SAMPLE_U8,              /**< Unsigned 8 Bit PCM */
 124     PA_SAMPLE_ALAW,            /**< 8 Bit a-Law */
 125     PA_SAMPLE_ULAW,            /**< 8 Bit mu-Law */
 126     PA_SAMPLE_S16LE,           /**< Signed 16 Bit PCM, little endian (PC) */
 127     PA_SAMPLE_S16BE,           /**< Signed 16 Bit PCM, big endian */
 128     PA_SAMPLE_FLOAT32LE,       /**< 32 Bit IEEE floating point, little endian, range -1 to 1 */
 129     PA_SAMPLE_FLOAT32BE,       /**< 32 Bit IEEE floating point, big endian, range -1 to 1 */
 130     PA_SAMPLE_S32LE,           /**< Signed 32 Bit PCM, little endian (PC) */
 131     PA_SAMPLE_S32BE,           /**< Signed 32 Bit PCM, big endian (PC) */
 132     PA_SAMPLE_MAX,             /**< Upper limit of valid sample types */
 133     PA_SAMPLE_INVALID = -1     /**< An invalid value */
 134 } pa_sample_format_t;
 135
 136 #ifdef WORDS_BIGENDIAN
 137 /** Signed 16 Bit PCM, native endian */
 138 #define PA_SAMPLE_S16NE PA_SAMPLE_S16BE
 139 /** 32 Bit IEEE floating point, native endian */
 140 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32BE
 141 /** Signed 32 Bit PCM, native endian */
 142 #define PA_SAMPLE_S32NE PA_SAMPLE_S32BE
 143 /** Signed 16 Bit PCM reverse endian */
 144 #define PA_SAMPLE_S16RE PA_SAMPLE_S16LE
 145 /** 32 Bit IEEE floating point, reverse endian */
 146 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32LE
 147 /** Signed 32 Bit PCM reverse endian */
 148 #define PA_SAMPLE_S32RE PA_SAMPLE_S32LE
 149 #else
 150 /** Signed 16 Bit PCM, native endian */
 151 #define PA_SAMPLE_S16NE PA_SAMPLE_S16LE
 152 /** 32 Bit IEEE floating point, native endian */
 153 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32LE
 154 /** Signed 32 Bit PCM, native endian */
 155 #define PA_SAMPLE_S32NE PA_SAMPLE_S32LE
 156 /** Signed 16 Bit PCM reverse endian */
 157 #define PA_SAMPLE_S16RE PA_SAMPLE_S16BE
 158 /** 32 Bit IEEE floating point, reverse endian */
 159 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32BE
 160 /** Signed 32 Bit PCM reverse endian */
 161 #define PA_SAMPLE_S32RE PA_SAMPLE_S32BE
 162 #endif
 163
 164 /** A Shortcut for PA_SAMPLE_FLOAT32NE */
 165 #define PA_SAMPLE_FLOAT32 PA_SAMPLE_FLOAT32NE
 166
 167 /** A sample format and attribute specification */
 168 typedef struct pa_sample_spec {
 169     pa_sample_format_t format;     /**< The sample format */
 170     uint32_t rate;                 /**< The sample rate. (e.g. 44100) */
 171     uint8_t channels;              /**< Audio channels. (1 for mono, 2 for stereo, ...) */
 172 } pa_sample_spec;
 173
 174 /** Type for usec specifications (unsigned). Always 64 bit. */
 175 typedef uint64_t pa_usec_t;
 176
 177 /** Return the amount of bytes playback of a second of audio with the specified sample type takes */
 178 size_t pa_bytes_per_second(const pa_sample_spec *spec) PA_GCC_PURE;
 179
 180 /** Return the size of a frame with the specific sample type */
 181 size_t pa_frame_size(const pa_sample_spec *spec) PA_GCC_PURE;
 182
 183 /** Return the size of a sample with the specific sample type */
 184 size_t pa_sample_size(const pa_sample_spec *spec) PA_GCC_PURE;
 185
 186 /** Calculate the time the specified bytes take to play with the specified sample type */
 187 pa_usec_t pa_bytes_to_usec(uint64_t length, const pa_sample_spec *spec) PA_GCC_PURE;
 188
 189 /** Calculates the number of bytes that are required for the specified time. \since 0.9 */
 190 size_t pa_usec_to_bytes(pa_usec_t t, const pa_sample_spec *spec) PA_GCC_PURE;
 191
 192 /** Return non-zero when the sample type specification is valid */
 193 int pa_sample_spec_valid(const pa_sample_spec *spec) PA_GCC_PURE;
 194
 195 /** Return non-zero when the two sample type specifications match */
 196 int pa_sample_spec_equal(const pa_sample_spec*a, const pa_sample_spec*b) PA_GCC_PURE;
 197
 198 /** Return a descriptive string for the specified sample format. \since 0.8 */
 199 const char *pa_sample_format_to_string(pa_sample_format_t f) PA_GCC_PURE;
 200
 201 /** Parse a sample format text. Inverse of pa_sample_format_to_string() */
 202 pa_sample_format_t pa_parse_sample_format(const char *format) PA_GCC_PURE;
 203
 204 /** Maximum required string length for pa_sample_spec_snprint() */
 205 #define PA_SAMPLE_SPEC_SNPRINT_MAX 32
 206
 207 /** Pretty print a sample type specification to a string */
 208 char* pa_sample_spec_snprint(char *s, size_t l, const pa_sample_spec *spec);
 209
 210 /** Pretty print a byte size value. (i.e. "2.5 MiB") */
 211 char* pa_bytes_snprint(char *s, size_t l, unsigned v);
 212
 213 PA_C_DECL_END
 214
 215 #endif