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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set et sw=2 ts=2: */
/***************************************************************************
* audioio.h
*
* Thu Sep 25 15:55:14 CEST 2014
* Copyright 2014 Bent Bisballe Nyeng
* deva@aasimon.org
****************************************************************************/
/*
* This file is part of LibAudioIO.
*
* LibAudioIO is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* LibAudioIO 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with LibAudioIO; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __LIBAUDIOIO_AUDIOIO_H__
#define __LIBAUDIOIO_AUDIOIO_H__
#ifdef __cplusplus
extern "C" {
#endif
#define NO_ERROR 0
#define OUT_OF_MEMORY -101
#define MISSING_HANDLE -102
#define MISSING_MIXER_HANDLE -102
#define MISSING_PCM_HANDLE -104
#define MIXER_INIT_FAILED -105
#define NO_SUCH_CHANNEL -106
#define SAMPLE_READ_ERROR -107
#define SAMPLE_WRITE_ERROR -108
#define MIXER_ERROR -109
#define COULD_NOT_OPEN_DEVICE -110
#define INVALID_MIXER_LEVEL -111
struct aio_t;
/**
* Initalise the AudioIO library and connect to a soundcard and a mixer.
* @param err An int pointer containing error value if function is unsuccessful.
* @param device A string containing the device name to connect to. A list
* possible devices can be seen with the 'aplay -L' command. The device
* "default" are usually the one needed.
* @param mixer A string containing the mixer interface to connect to. A list
* of possible interfaces can be seen with the 'amixer scontrols' command.
* Usually the interface "Capture" is the one needed.
* @param samplerate An unsigned integer containing the desired samplerate in
* Hertz.
* @param channels An unsigned integer containing the desired number of
* channels. The channel samples will be interleaved in the data stream whe
* ai_read is called.
* @return A pointer to the newly created handle or NULL on failure.
*/
struct aio_t *aio_init(int *err,
const char *playback_device,
const char *playback_mixer,
const char *capture_device,
const char *capture_mixer,
unsigned int samplerate,
unsigned int channels);
/**
* Read samples from the soundcard.
* @param err An int pointer containing error value if function is unsuccessful.
* @param handle A pointer to the handle to be used.
* @param pcm Buffer cotaining which will be filled with samples.
* @param maxsize The maximum number of bytes (not samples) to read.
* @return Returns the number of bytes (not samples) read or -1 on error.
* NOTE: to get the number of samples read, devide the return value with the
* sample width (2 bytes / 16 bits) and the number of interleaved channels
* (usually 1 or 2).
*/
int aio_read(struct aio_t *handle, char *pcm, unsigned int maxsize);
/**
* Write samples to the soundcard.
* @param err An int pointer containing error value if function is unsuccessful.
* @param handle A pointer to the handle to be used.
* @param size The maximum number of bytes (not samples) to be written.
* @return Returns the number of bytes (not samples) written or -1 on error.
* NOTE: to get the number of samples read, devide the return value with the
* sample width (2 bytes / 16 bits) and the number of interleaved channels
* (usually 1 or 2).
*/
int aio_write(struct aio_t *handle, const char *pcm, unsigned int size);
/**
* Adjust playback channel mixer levels.
* @param handle A pointer to the handle to be used.
* @param channel The channel number to set mixer level of. 0 or 1 should be
* used for the two channels of a stereo interface.
* @param level The mixer level to set in dB
* @return Returns error code.
*/
int aio_set_playback_mixer_level(struct aio_t *handle, unsigned int channel,
float level);
/**
* Get playback channel mixer levels.
* @param handle A pointer to the handle to be used.
* @param channel The channel number to get mixer level of. 0 or 1 should be
* used for the two channels of a stereo interface.
* @param level A pointer to a float which after a successful call will contain
* the channel amplification level in dB.
* @return Returns error code.
*/
int aio_get_playback_mixer_level(struct aio_t *handle, unsigned int channel,
float *level);
/**
* Get playback channel amplification range in dB.
* @param handle A pointer to the handle to be used.
* @param min A pointer to a float in which the min value will be returned.
* @param max A pointer to a float in which the max value will be returned.
* @return Returns error code.
*/
int aio_get_playback_mixer_level_range(struct aio_t *handle,
float *min, float *max);
/**
* Adjust capture channel mixer levels.
* @param handle A pointer to the handle to be used.
* @param channel The channel number to set mixer level of. 0 or 1 should be
* used for the two channels of a stereo interface.
* @param level The mixer level to set in dB
* @return Returns error code.
*/
int aio_set_capture_mixer_level(struct aio_t *handle, unsigned int channel,
float level);
/**
* Get channel mixer levels.
* @param handle A pointer to the handle to be used.
* @param channel The channel number to get mixer level of. 0 or 1 should be
* used for the two channels of a stereo interface.
* @param level A pointer to a float which after a successful call will contain
* the channel amplification level in dB.
* @return Returns error code.
*/
int aio_get_capture_mixer_level(struct aio_t *handle, unsigned int channel,
float *level);
/**
* Get capture channel amplification range in dB.
* @param handle A pointer to the handle to be used.
* @param min A pointer to a float in which the min value will be returned.
* @param max A pointer to a float in which the max value will be returned.
* @return Returns error code.
*/
int aio_get_capture_mixer_level_range(struct aio_t *handle,
float *min, float *max);
/**
* Get actual samplerate.
* The samplerate set in ai_init may or may not match a possible samplerate for
* the audio hardware and therefore the ALSA library might decide to use another
* samplerate than the one specified.
* This function can be called to obtain the actual samplerate that the hardware
* has been configured to use.
* @param err An int pointer containing error value if function is unsuccessful.
* @param handle A pointer to the handle to be used.
* @return The samplerate as an integer or -1 on error.
*/
int aio_get_samplerate(struct aio_t *handle);
int aio_get_buffer_size(struct aio_t *handle);
/**
* Close and free the handle.
* @param err An int pointer containing error value if function is unsuccessful.
* @param handle A pointer to the handle to be closed.
*/
int aio_close(struct aio_t *handle);
#ifdef __cplusplus
}
#endif
#endif/*__LIBAUDIOIO_AUDIOIO_H__*/
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