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/gccmacro.h>
  34 #include <pulse/cdecl.h>
  35
  36 /** \page sample Sample Format Specifications
  37  *
  38  * \section overv_sec Overview
  39  *
  40  * PulseAudio is capable of handling a multitude of sample formats, rates
  41  * and channels, transparently converting and mixing them as needed.
  42  *
  43  * \section format_sec Sample Format
  44  *
  45  * PulseAudio supports the following sample formats:
  46  *
  47  * \li PA_SAMPLE_U8 - Unsigned 8 bit integer PCM.
  48  * \li PA_SAMPLE_S16LE - Signed 16 integer bit PCM, little endian.
  49  * \li PA_SAMPLE_S16BE - Signed 16 integer bit PCM, big endian.
  50  * \li PA_SAMPLE_FLOAT32LE - 32 bit IEEE floating point PCM, little endian.
  51  * \li PA_SAMPLE_FLOAT32BE - 32 bit IEEE floating point PCM, big endian.
  52  * \li PA_SAMPLE_ALAW - 8 bit a-Law.
  53  * \li PA_SAMPLE_ULAW - 8 bit mu-Law.
  54  * \li PA_SAMPLE_S32LE - Signed 32 bit integer PCM, little endian.
  55  * \li PA_SAMPLE_S32BE - Signed 32 bit integer PCM, big endian.
  56  *
  57  * The floating point sample formats have the range from -1 to 1.
  58  *
  59  * The sample formats that are sensitive to endianness have convenience
  60  * macros for native endian (NE), and reverse endian (RE).
  61  *
  62  * \section rate_sec Sample Rates
  63  *
  64  * PulseAudio supports any sample rate between 1 Hz and 4 GHz. There is no
  65  * point trying to exceed the sample rate of the output device though as the
  66  * signal will only get downsampled, consuming CPU on the machine running the
  67  * server.
  68  *
  69  * \section chan_sec Channels
  70  *
  71  * PulseAudio supports up to 16 individiual channels. The order of the
  72  * channels is up to the application, but they must be continous. To map
  73  * channels to speakers, see \ref channelmap.
  74  *
  75  * \section calc_sec Calculations
  76  *
  77  * The PulseAudio library contains a number of convenience functions to do
  78  * calculations on sample formats:
  79  *
  80  * \li pa_bytes_per_second() - The number of bytes one second of audio will
  81  *                             take given a sample format.
  82  * \li pa_frame_size() - The size, in bytes, of one frame (i.e. one set of
  83  *                       samples, one for each channel).
  84  * \li pa_sample_size() - The size, in bytes, of one sample.
  85  * \li pa_bytes_to_usec() - Calculate the time it would take to play a buffer
  86  *                          of a certain size.
  87  *
  88  * \section util_sec Convenience Functions
  89  *
  90  * The library also contains a couple of other convenience functions:
  91  *
  92  * \li pa_sample_spec_valid() - Tests if a sample format specification is
  93  *                              valid.
  94  * \li pa_sample_spec_equal() - Tests if the sample format specifications are
  95  *                              identical.
  96  * \li pa_sample_format_to_string() - Return a textual description of a
  97  *                                    sample format.
  98  * \li pa_parse_sample_format() - Parse a text string into a sample format.
  99  * \li pa_sample_spec_snprint() - Create a textual description of a complete
 100  *                                 sample format specification.
 101  * \li pa_bytes_snprint() - Pretty print a byte value (e.g. 2.5 MiB).
 102  */
 103
 104 /** \file
 105  * Constants and routines for sample type handling */
 106
 107 PA_C_DECL_BEGIN
 108
 109 #if !defined(WORDS_BIGENDIAN)
 110 #if defined(__BYTE_ORDER)
 111 #if __BYTE_ORDER == __BIG_ENDIAN
 112 #define WORDS_BIGENDIAN
 113 #endif
 114 #endif
 115 #endif
 116
 117 /** Maximum number of allowed channels */
 118 #define PA_CHANNELS_MAX 32U
 119
 120 /** Maximum allowed sample rate */
 121 #define PA_RATE_MAX (48000U*4U)
 122
 123 /** Sample format */
 124 typedef enum pa_sample_format {
 125     PA_SAMPLE_U8,              /**< Unsigned 8 Bit PCM */
 126     PA_SAMPLE_ALAW,            /**< 8 Bit a-Law */
 127     PA_SAMPLE_ULAW,            /**< 8 Bit mu-Law */
 128     PA_SAMPLE_S16LE,           /**< Signed 16 Bit PCM, little endian (PC) */
 129     PA_SAMPLE_S16BE,           /**< Signed 16 Bit PCM, big endian */
 130     PA_SAMPLE_FLOAT32LE,       /**< 32 Bit IEEE floating point, little endian, range -1 to 1 */
 131     PA_SAMPLE_FLOAT32BE,       /**< 32 Bit IEEE floating point, big endian, range -1 to 1 */
 132     PA_SAMPLE_S32LE,           /**< Signed 32 Bit PCM, little endian (PC) */
 133     PA_SAMPLE_S32BE,           /**< Signed 32 Bit PCM, big endian (PC) */
 134     PA_SAMPLE_MAX,             /**< Upper limit of valid sample types */
 135     PA_SAMPLE_INVALID = -1     /**< An invalid value */
 136 } pa_sample_format_t;
 137
 138 #ifdef WORDS_BIGENDIAN
 139 /** Signed 16 Bit PCM, native endian */
 140 #define PA_SAMPLE_S16NE PA_SAMPLE_S16BE
 141 /** 32 Bit IEEE floating point, native endian */
 142 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32BE
 143 /** Signed 32 Bit PCM, native endian */
 144 #define PA_SAMPLE_S32NE PA_SAMPLE_S32BE
 145 /** Signed 16 Bit PCM reverse endian */
 146 #define PA_SAMPLE_S16RE PA_SAMPLE_S16LE
 147 /** 32 Bit IEEE floating point, reverse endian */
 148 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32LE
 149 /** Signed 32 Bit PCM reverse endian */
 150 #define PA_SAMPLE_S32RE PA_SAMPLE_S32LE
 151 #else
 152 /** Signed 16 Bit PCM, native endian */
 153 #define PA_SAMPLE_S16NE PA_SAMPLE_S16LE
 154 /** 32 Bit IEEE floating point, native endian */
 155 #define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32LE
 156 /** Signed 32 Bit PCM, native endian */
 157 #define PA_SAMPLE_S32NE PA_SAMPLE_S32LE
 158 /** Signed 16 Bit PCM reverse endian */
 159 #define PA_SAMPLE_S16RE PA_SAMPLE_S16BE
 160 /** 32 Bit IEEE floating point, reverse endian */
 161 #define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32BE
 162 /** Signed 32 Bit PCM reverse endian */
 163 #define PA_SAMPLE_S32RE PA_SAMPLE_S32BE
 164 #endif
 165
 166 /** A Shortcut for PA_SAMPLE_FLOAT32NE */
 167 #define PA_SAMPLE_FLOAT32 PA_SAMPLE_FLOAT32NE
 168
 169 /** A sample format and attribute specification */
 170 typedef struct pa_sample_spec {
 171     pa_sample_format_t format;     /**< The sample format */
 172     uint32_t rate;                 /**< The sample rate. (e.g. 44100) */
 173     uint8_t channels;              /**< Audio channels. (1 for mono, 2 for stereo, ...) */
 174 } pa_sample_spec;
 175
 176 /** Type for usec specifications (unsigned). Always 64 bit. */
 177 typedef uint64_t pa_usec_t;
 178
 179 /** Return the amount of bytes playback of a second of audio with the specified sample type takes */
 180 size_t pa_bytes_per_second(const pa_sample_spec *spec) PA_GCC_PURE;
 181
 182 /** Return the size of a frame with the specific sample type */
 183 size_t pa_frame_size(const pa_sample_spec *spec) PA_GCC_PURE;
 184
 185 /** Return the size of a sample with the specific sample type */
 186 size_t pa_sample_size(const pa_sample_spec *spec) PA_GCC_PURE;
 187
 188 /** Calculate the time the specified bytes take to play with the specified sample type */
 189 pa_usec_t pa_bytes_to_usec(uint64_t length, const pa_sample_spec *spec) PA_GCC_PURE;
 190
 191 /** Calculates the number of bytes that are required for the specified time. \since 0.9 */
 192 size_t pa_usec_to_bytes(pa_usec_t t, const pa_sample_spec *spec) PA_GCC_PURE;
 193
 194 /** Return non-zero when the sample type specification is valid */
 195 int pa_sample_spec_valid(const pa_sample_spec *spec) PA_GCC_PURE;
 196
 197 /** Return non-zero when the two sample type specifications match */
 198 int pa_sample_spec_equal(const pa_sample_spec*a, const pa_sample_spec*b) PA_GCC_PURE;
 199
 200 /** Return a descriptive string for the specified sample format. \since 0.8 */
 201 const char *pa_sample_format_to_string(pa_sample_format_t f) PA_GCC_PURE;
 202
 203 /** Parse a sample format text. Inverse of pa_sample_format_to_string() */
 204 pa_sample_format_t pa_parse_sample_format(const char *format) PA_GCC_PURE;
 205
 206 /** Maximum required string length for pa_sample_spec_snprint() */
 207 #define PA_SAMPLE_SPEC_SNPRINT_MAX 32
 208
 209 /** Pretty print a sample type specification to a string */
 210 char* pa_sample_spec_snprint(char *s, size_t l, const pa_sample_spec *spec);
 211
 212 /** Pretty print a byte size value. (i.e. "2.5 MiB") */
 213 char* pa_bytes_snprint(char *s, size_t l, unsigned v);
 214
 215 PA_C_DECL_END
 216
 217 #endif