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git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@2098 fefdeb5f-60dc-0310-8127-8f9354f1896f
216 lines
8.3 KiB
C
216 lines
8.3 KiB
C
#ifndef foosamplehfoo
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#define foosamplehfoo
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/* $Id$ */
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/***
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This file is part of PulseAudio.
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Copyright 2004-2006 Lennart Poettering
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Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
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PulseAudio is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published
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by the Free Software Foundation; either version 2 of the License,
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or (at your option) any later version.
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PulseAudio is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with PulseAudio; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
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USA.
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***/
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#include <inttypes.h>
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#include <sys/types.h>
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#include <sys/param.h>
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#include <math.h>
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#include <pulse/cdecl.h>
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/** \page sample Sample Format Specifications
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*
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* \section overv_sec Overview
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*
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* PulseAudio is capable of handling a multitude of sample formats, rates
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* and channels, transparently converting and mixing them as needed.
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*
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* \section format_sec Sample Format
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*
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* PulseAudio supports the following sample formats:
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*
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* \li PA_SAMPLE_U8 - Unsigned 8 bit integer PCM.
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* \li PA_SAMPLE_S16LE - Signed 16 integer bit PCM, little endian.
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* \li PA_SAMPLE_S16BE - Signed 16 integer bit PCM, big endian.
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* \li PA_SAMPLE_FLOAT32LE - 32 bit IEEE floating point PCM, little endian.
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* \li PA_SAMPLE_FLOAT32BE - 32 bit IEEE floating point PCM, big endian.
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* \li PA_SAMPLE_ALAW - 8 bit a-Law.
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* \li PA_SAMPLE_ULAW - 8 bit mu-Law.
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* \li PA_SAMPLE_S32LE - Signed 32 bit integer PCM, little endian.
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* \li PA_SAMPLE_S32BE - Signed 32 bit integer PCM, big endian.
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*
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* The floating point sample formats have the range from -1 to 1.
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*
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* The sample formats that are sensitive to endianness have convenience
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* macros for native endian (NE), and reverse endian (RE).
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*
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* \section rate_sec Sample Rates
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*
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* PulseAudio supports any sample rate between 1 Hz and 4 GHz. There is no
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* point trying to exceed the sample rate of the output device though as the
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* signal will only get downsampled, consuming CPU on the machine running the
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* server.
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*
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* \section chan_sec Channels
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*
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* PulseAudio supports up to 16 individiual channels. The order of the
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* channels is up to the application, but they must be continous. To map
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* channels to speakers, see \ref channelmap.
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*
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* \section calc_sec Calculations
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*
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* The PulseAudio library contains a number of convenience functions to do
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* calculations on sample formats:
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*
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* \li pa_bytes_per_second() - The number of bytes one second of audio will
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* take given a sample format.
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* \li pa_frame_size() - The size, in bytes, of one frame (i.e. one set of
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* samples, one for each channel).
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* \li pa_sample_size() - The size, in bytes, of one sample.
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* \li pa_bytes_to_usec() - Calculate the time it would take to play a buffer
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* of a certain size.
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*
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* \section util_sec Convenience Functions
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*
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* The library also contains a couple of other convenience functions:
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*
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* \li pa_sample_spec_valid() - Tests if a sample format specification is
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* valid.
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* \li pa_sample_spec_equal() - Tests if the sample format specifications are
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* identical.
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* \li pa_sample_format_to_string() - Return a textual description of a
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* sample format.
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* \li pa_parse_sample_format() - Parse a text string into a sample format.
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* \li pa_sample_spec_snprint() - Create a textual description of a complete
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* sample format specification.
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* \li pa_bytes_snprint() - Pretty print a byte value (e.g. 2.5 MiB).
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*/
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/** \file
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* Constants and routines for sample type handling */
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PA_C_DECL_BEGIN
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#if !defined(WORDS_BIGENDIAN)
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#if defined(__BYTE_ORDER)
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#if __BYTE_ORDER == __BIG_ENDIAN
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#define WORDS_BIGENDIAN
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#endif
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#endif
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#endif
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/** Maximum number of allowed channels */
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#define PA_CHANNELS_MAX 32
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/** Maximum allowed sample rate */
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#define PA_RATE_MAX (48000*4)
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/** Sample format */
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typedef enum pa_sample_format {
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PA_SAMPLE_U8, /**< Unsigned 8 Bit PCM */
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PA_SAMPLE_ALAW, /**< 8 Bit a-Law */
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PA_SAMPLE_ULAW, /**< 8 Bit mu-Law */
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PA_SAMPLE_S16LE, /**< Signed 16 Bit PCM, little endian (PC) */
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PA_SAMPLE_S16BE, /**< Signed 16 Bit PCM, big endian */
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PA_SAMPLE_FLOAT32LE, /**< 32 Bit IEEE floating point, little endian, range -1 to 1 */
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PA_SAMPLE_FLOAT32BE, /**< 32 Bit IEEE floating point, big endian, range -1 to 1 */
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PA_SAMPLE_S32LE, /**< Signed 32 Bit PCM, little endian (PC) */
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PA_SAMPLE_S32BE, /**< Signed 32 Bit PCM, big endian (PC) */
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PA_SAMPLE_MAX, /**< Upper limit of valid sample types */
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PA_SAMPLE_INVALID = -1 /**< An invalid value */
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} pa_sample_format_t;
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#ifdef WORDS_BIGENDIAN
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/** Signed 16 Bit PCM, native endian */
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#define PA_SAMPLE_S16NE PA_SAMPLE_S16BE
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/** 32 Bit IEEE floating point, native endian */
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#define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32BE
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/** Signed 32 Bit PCM, native endian */
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#define PA_SAMPLE_S32NE PA_SAMPLE_S32BE
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/** Signed 16 Bit PCM reverse endian */
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#define PA_SAMPLE_S16RE PA_SAMPLE_S16LE
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/** 32 Bit IEEE floating point, reverse endian */
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#define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32LE
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/** Signed 32 Bit PCM reverse endian */
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#define PA_SAMPLE_S32RE PA_SAMPLE_S32LE
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#else
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/** Signed 16 Bit PCM, native endian */
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#define PA_SAMPLE_S16NE PA_SAMPLE_S16LE
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/** 32 Bit IEEE floating point, native endian */
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#define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32LE
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/** Signed 32 Bit PCM, native endian */
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#define PA_SAMPLE_S32NE PA_SAMPLE_S32LE
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/** Signed 16 Bit PCM reverse endian */
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#define PA_SAMPLE_S16RE PA_SAMPLE_S16BE
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/** 32 Bit IEEE floating point, reverse endian */
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#define PA_SAMPLE_FLOAT32RE PA_SAMPLE_FLOAT32BE
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/** Signed 32 Bit PCM reverse endian */
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#define PA_SAMPLE_S32RE PA_SAMPLE_S32BE
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#endif
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/** A Shortcut for PA_SAMPLE_FLOAT32NE */
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#define PA_SAMPLE_FLOAT32 PA_SAMPLE_FLOAT32NE
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/** A sample format and attribute specification */
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typedef struct pa_sample_spec {
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pa_sample_format_t format; /**< The sample format */
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uint32_t rate; /**< The sample rate. (e.g. 44100) */
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uint8_t channels; /**< Audio channels. (1 for mono, 2 for stereo, ...) */
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} pa_sample_spec;
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/** Type for usec specifications (unsigned). May be either 32 or 64 bit, depending on the architecture */
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typedef uint64_t pa_usec_t;
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/** Return the amount of bytes playback of a second of audio with the specified sample type takes */
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size_t pa_bytes_per_second(const pa_sample_spec *spec) PA_GCC_PURE;
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/** Return the size of a frame with the specific sample type */
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size_t pa_frame_size(const pa_sample_spec *spec) PA_GCC_PURE;
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/** Return the size of a sample with the specific sample type */
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size_t pa_sample_size(const pa_sample_spec *spec) PA_GCC_PURE;
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/** Calculate the time the specified bytes take to play with the specified sample type */
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pa_usec_t pa_bytes_to_usec(uint64_t length, const pa_sample_spec *spec) PA_GCC_PURE;
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/** Calculates the number of bytes that are required for the specified time. \since 0.9 */
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size_t pa_usec_to_bytes(pa_usec_t t, const pa_sample_spec *spec) PA_GCC_PURE;
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/** Return non-zero when the sample type specification is valid */
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int pa_sample_spec_valid(const pa_sample_spec *spec) PA_GCC_PURE;
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/** Return non-zero when the two sample type specifications match */
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int pa_sample_spec_equal(const pa_sample_spec*a, const pa_sample_spec*b) PA_GCC_PURE;
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/** Return a descriptive string for the specified sample format. \since 0.8 */
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const char *pa_sample_format_to_string(pa_sample_format_t f) PA_GCC_PURE;
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/** Parse a sample format text. Inverse of pa_sample_format_to_string() */
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pa_sample_format_t pa_parse_sample_format(const char *format) PA_GCC_PURE;
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/** Maximum required string length for pa_sample_spec_snprint() */
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#define PA_SAMPLE_SPEC_SNPRINT_MAX 32
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/** Pretty print a sample type specification to a string */
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char* pa_sample_spec_snprint(char *s, size_t l, const pa_sample_spec *spec);
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/** Pretty print a byte size value. (i.e. "2.5 MiB") */
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char* pa_bytes_snprint(char *s, size_t l, unsigned v);
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PA_C_DECL_END
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#endif
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