pulseaudio/polyp/sample.h

#ifndef foosamplehfoo
#define foosamplehfoo

/* $Id$ */

/***
  This file is part of polypaudio.
 
  polypaudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published
  by the Free Software Foundation; either version 2 of the License,
  or (at your option) any later version.
 
  polypaudio is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with polypaudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#include <inttypes.h>
#include <sys/types.h>
#include <math.h>

#include "cdecl.h"

/** \file
 * Constants and routines for sample type handling */

PA_C_DECL_BEGIN

/** Sample format */
enum pa_sample_format {
    PA_SAMPLE_U8,              /**< Unsigned 8 Bit PCM */
    PA_SAMPLE_ALAW,            /**< 8 Bit a-Law */
    PA_SAMPLE_ULAW,            /**< 8 Bit mu-Law */
    PA_SAMPLE_S16LE,           /**< Signed 16 Bit PCM, little endian (PC) */
    PA_SAMPLE_S16BE,           /**< Signed 16 Bit PCM, big endian */
    PA_SAMPLE_FLOAT32LE,       /**< 32 Bit IEEE floating point, little endian, range -1..1 */
    PA_SAMPLE_FLOAT32BE,       /**< 32 Bit IEEE floating point, big endian, range -1..1 */
    PA_SAMPLE_MAX              /**< Upper limit of valid sample types */
};

#ifdef WORDS_BIGENDIAN
/** Signed 16 Bit PCM, native endian */
#define PA_SAMPLE_S16NE PA_SAMPLE_S16BE
/** 32 Bit IEEE floating point, native endian */
#define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32BE
#else
/** Signed 16 Bit PCM, native endian */
#define PA_SAMPLE_S16NE PA_SAMPLE_S16LE
/** 32 Bit IEEE floating point, native endian */
#define PA_SAMPLE_FLOAT32NE PA_SAMPLE_FLOAT32LE
#endif

/** A Shortcut for PA_SAMPLE_FLOAT32NE */
#define PA_SAMPLE_FLOAT32 PA_SAMPLE_FLOAT32NE

/** A sample format and attribute specification */
struct pa_sample_spec {
    enum pa_sample_format format;  /**< The sample format */
    uint32_t rate;                 /**< The sample rate. (e.g. 44100) */
    uint8_t channels;              /**< Audio channels. (1 for mono, 2 for stereo, ...) */
};

/** Type for usec specifications */
typedef uint32_t pa_usec_t;

/** Return the amount of bytes playback of a second of audio with the speicified sample type takes */
size_t pa_bytes_per_second(const struct pa_sample_spec *spec);

/** Return the size of a frame with the specific sample type */
size_t pa_frame_size(const struct pa_sample_spec *spec);

/** Calculate the time the specified bytes take to play with the specified sample type */
pa_usec_t pa_bytes_to_usec(size_t length, const struct pa_sample_spec *spec);

/** Return non-zero when the sample type specification is valid */
int pa_sample_spec_valid(const struct pa_sample_spec *spec);

/** Return non-zero when the two sample type specifications match */
int pa_sample_spec_equal(const struct pa_sample_spec*a, const struct pa_sample_spec*b);

/** Maximum required string length for pa_sample_spec_snprint() */
#define PA_SAMPLE_SNPRINT_MAX_LENGTH 32

/** Pretty print a sample type specification to a string */
void pa_sample_spec_snprint(char *s, size_t l, const struct pa_sample_spec *spec);

/** Volume specification: 0: silence; < 256: diminished volume; 256: normal volume; > 256 amplified volume */
typedef uint32_t pa_volume_t;

/** Normal volume (100%) */
#define PA_VOLUME_NORM (0x100)

/** Muted volume (0%) */
#define PA_VOLUME_MUTED (0)

/** Multiply two volumes specifications, return the result. This uses PA_VOLUME_NORM as neutral element of multiplication. */
pa_volume_t pa_volume_multiply(pa_volume_t a, pa_volume_t b);

/** Convert volume from decibel to linear level. \since 0.4 */
pa_volume_t pa_volume_from_dB(double f);

/** Convert volume from linear level to decibel.  \since 0.4 */
double pa_volume_to_dB(pa_volume_t v);

#ifdef INFINITY
#define PA_DECIBEL_MININFTY (-INFINITY)
#else
/** This value is used as minus infinity when using pa_volume_{to,from}_dB(). \since 0.4 */
#define PA_DECIBEL_MININFTY (-200)
#endif

/** Pretty print a byte size value. (i.e. "2.5 MB") */
void pa_bytes_snprint(char *s, size_t l, off_t v);

PA_C_DECL_END

#endif