This document describes the libdsp library for development purposes. It's a very 
convenient library which works both with OSS and ALSA APIs, written for the 
VoiceAuth project.


Sound card manipulation:
------------------------
#include <libdsp/sound.h>

dsp_t open_dsp(char *device, int *format, int flags);

int close_dsp(dsp_t fd);

audio_data_t * read_dsp(int use_select, int read_timeout, 
                        float silence_level, float threshold, 
                        int format, dsp_t fd);

int write_dsp(int use_select, int select_timeout, audio_data_t *data, 
              int format, dsp_t fd);



Mixer manipulation:
-------------------
#include <libdsp/sound.h>

mixer_t open_mixer(char *device, int flags);

void close_mixer(mixer_t fd);

int set_mixer_recdev(int channel, mixer_t fd);

int set_mixer_volume(int channel, int igain, mixer_t fd);



Signal processing helpers:
--------------------------
#include <libdsp/sound.h>

int get_silence_level(int use_select, int format, dsp_t fd);

audio_data_t * remove_silence(audio_data_t *dsp_data, int silence_level, float threshold);



Audio stream helpers:
---------------------
#include <libdsp/sound.h>

audio_data_t * new_audio_data(int len);

void free_audio_data(audio_data_t *data);

audio_data_t * resize_float_stream(audio_data_t *speech, int new_len);



Data and config information:
----------------------------
#include <libdsp/sound.h>

char * audio_format_str (int);
int get_audio_driver();
//void get_audio_config(int *audio_format, int *channels, int *sampling_rate);
//char *translate_audio_format(int audio_format);