ref: ee04582dff89592efbd9b2051f061ffc7f63e8cc
dir: /src/samplerate.h/
/* ** Copyright (c) 2002-2016, Erik de Castro Lopo <[email protected]> ** All rights reserved. ** ** This code is released under 2-clause BSD license. Please see the ** file at : https://github.com/libsndfile/libsamplerate/blob/master/COPYING */ /* ** API documentation is available here: ** http://libsndfile.github.io/libsamplerate/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) ; /* ** Clone a handle : return an anonymous pointer to a new converter ** containing the same internal state as orig. Error returned in *error. */ SRC_STATE* src_clone (SRC_STATE* orig, 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 */