ref: 83a9482e8049c7eb96a305516fe5efca570b0a3a
dir: /src/samplerate.h/
/*
** Copyright (c) 2002-2016, Erik de Castro Lopo <erikd@mega-nerd.com>
** All rights reserved.
**
** This code is released under 2-clause BSD license. Please see the
** file at : https://github.com/erikd/libsamplerate/blob/master/COPYING
*/
/*
** API documentation is available here:
** http://www.mega-nerd.com/SRC/api.html
*/
#ifndef SAMPLERATE_H
#define SAMPLERATE_H
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/* Opaque data type SRC_STATE. */
typedef struct SRC_STATE_tag SRC_STATE ;
/* SRC_DATA is used to pass data to src_simple() and src_process(). */
typedef struct
{ const float *data_in ;
float *data_out ;
long input_frames, output_frames ;
long input_frames_used, output_frames_gen ;
int end_of_input ;
double src_ratio ;
} SRC_DATA ;
/*
** User supplied callback function type for use with src_callback_new()
** and src_callback_read(). First parameter is the same pointer that was
** passed into src_callback_new(). Second parameter is pointer to a
** pointer. The user supplied callback function must modify *data to
** point to the start of the user supplied float array. The user supplied
** function must return the number of frames that **data points to.
*/
typedef long (*src_callback_t) (void *cb_data, float **data) ;
/*
** Standard initialisation function : return an anonymous pointer to the
** internal state of the converter. Choose a converter from the enums below.
** Error returned in *error.
*/
SRC_STATE* src_new (int converter_type, int channels, int *error) ;
/*
** Initilisation for callback based API : return an anonymous pointer to the
** internal state of the converter. Choose a converter from the enums below.
** The cb_data pointer can point to any data or be set to NULL. Whatever the
** value, when processing, user supplied function "func" gets called with
** cb_data as first parameter.
*/
SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels,
int *error, void* cb_data) ;
/*
** Cleanup all internal allocations.
** Always returns NULL.
*/
SRC_STATE* src_delete (SRC_STATE *state) ;
/*
** Standard processing function.
** Returns non zero on error.
*/
int src_process (SRC_STATE *state, SRC_DATA *data) ;
/*
** Callback based processing function. Read up to frames worth of data from
** the converter int *data and return frames read or -1 on error.
*/
long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ;
/*
** Simple interface for performing a single conversion from input buffer to
** output buffer at a fixed conversion ratio.
** Simple interface does not require initialisation as it can only operate on
** a single buffer worth of audio.
*/
int src_simple (SRC_DATA *data, int converter_type, int channels) ;
/*
** This library contains a number of different sample rate converters,
** numbered 0 through N.
**
** Return a string giving either a name or a more full description of each
** sample rate converter or NULL if no sample rate converter exists for
** the given value. The converters are sequentially numbered from 0 to N.
*/
const char *src_get_name (int converter_type) ;
const char *src_get_description (int converter_type) ;
const char *src_get_version (void) ;
/*
** Set a new SRC ratio. This allows step responses
** in the conversion ratio.
** Returns non zero on error.
*/
int src_set_ratio (SRC_STATE *state, double new_ratio) ;
/*
** Get the current channel count.
** Returns negative on error, positive channel count otherwise
*/
int src_get_channels (SRC_STATE *state) ;
/*
** Reset the internal SRC state.
** Does not modify the quality settings.
** Does not free any memory allocations.
** Returns non zero on error.
*/
int src_reset (SRC_STATE *state) ;
/*
** Return TRUE if ratio is a valid conversion ratio, FALSE
** otherwise.
*/
int src_is_valid_ratio (double ratio) ;
/*
** Return an error number.
*/
int src_error (SRC_STATE *state) ;
/*
** Convert the error number into a string.
*/
const char* src_strerror (int error) ;
/*
** The following enums can be used to set the interpolator type
** using the function src_set_converter().
*/
enum
{
SRC_SINC_BEST_QUALITY = 0,
SRC_SINC_MEDIUM_QUALITY = 1,
SRC_SINC_FASTEST = 2,
SRC_ZERO_ORDER_HOLD = 3,
SRC_LINEAR = 4,
} ;
/*
** Extra helper functions for converting from short to float and
** back again.
*/
void src_short_to_float_array (const short *in, float *out, int len) ;
void src_float_to_short_array (const float *in, short *out, int len) ;
void src_int_to_float_array (const int *in, float *out, int len) ;
void src_float_to_int_array (const float *in, int *out, int len) ;
#ifdef __cplusplus
} /* extern "C" */
#endif /* __cplusplus */
#endif /* SAMPLERATE_H */