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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/***************************************************************************
* audioin.h
*
* Wed Sep 30 11:36:18 CEST 2009
* Copyright 2011 Bent Bisballe Nyeng
* deva@aasimon.org
****************************************************************************/
/*
* This file is part of libaudioin.
*
* libaudioin 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.
*
* libaudioin 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 libaudioin; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#ifndef __LIBAUDIOIN_AUDIOIN_H__
#define __LIBAUDIOIN_AUDIOIN_H__
#ifdef __cplusplus
extern "C" {
#endif
#define NO_ERROR 0
#define OUT_OF_MEMORY 101
#define MISSING_HANDLE 102
#define COULD_NOT_OPEN_DEVICE 203
#define COULD_NOT_SET_HW_PARAMS 204
#define COULD_NOT_INIT_PARAMS 205
#define COULD_NOT_SET_ACCESS_MODE 206
#define COULD_NOT_SET_FORMAT 207
#define COULD_NOT_SET_CHANNELS 208
#define COULD_NOT_SET_SAMPLE_RATE 209
#define COULD_NOT_SET_PERIOD_SIZE 210
#define BUFFER_TOO_SMALL 305
#define BUFFER_OVERRUN 306
#define READ_ERROR 307
#define SHORT_READ 308
#define MIXER_INIT_FAILED 400
#define MIXER_NOT_INITIALISED 401
#define INVALID_MIXER_LEVEL 402
#define INVALID_CHANNEL_NUMBER 403
#define COULD_NOT_SET_MIXER_LEVEL 404
struct ai_t;
/**
* Initalise the AudioIn 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 ai_t *ai_init(int *err, const char *device, const char *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 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 ai_read(int *err, struct ai_t *handle, void *pcm, unsigned int maxsize);
/**
* Adjust channel mixer levels.
* @param err An int pointer containing error value if function is unsuccessful.
* @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, ranging from 0.0 to 1.0 where 0.0 is
* mute and 1.0 is maximum gain.
* @return Returns -1 on error 0 otherwise.
*/
int ai_set_mixer_level(int *err, struct ai_t *handle, unsigned int channel,
float level);
/**
* 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 ai_get_samplerate(int *err, struct ai_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.
*/
void ai_close(int *err, struct ai_t *handle);
#ifdef __cplusplus
}
#endif
#endif/*__LIBAUDIOIN_AUDIOIN_H__*/
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