Jack2 1.9.6
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00001 /* 00002 ** Copyright (C) 2002-2008 Erik de Castro Lopo <erikd@mega-nerd.com> 00003 ** 00004 ** This program is free software; you can redistribute it and/or modify 00005 ** it under the terms of the GNU General Public License as published by 00006 ** the Free Software Foundation; either version 2 of the License, or 00007 ** (at your option) any later version. 00008 ** 00009 ** This program is distributed in the hope that it will be useful, 00010 ** but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00012 ** GNU General Public License for more details. 00013 ** 00014 ** You should have received a copy of the GNU General Public License 00015 ** along with this program; if not, write to the Free Software 00016 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. 00017 */ 00018 00019 /* 00020 ** This code is part of Secret Rabibt Code aka libsamplerate. A commercial 00021 ** use license for this code is available, please see: 00022 ** http://www.mega-nerd.com/SRC/procedure.html 00023 */ 00024 00025 /* 00026 ** API documentation is available here: 00027 ** http://www.mega-nerd.com/SRC/api.html 00028 */ 00029 00030 #ifndef SAMPLERATE_H 00031 #define SAMPLERATE_H 00032 00033 #ifdef __cplusplus 00034 extern "C" { 00035 #endif /* __cplusplus */ 00036 00037 00038 /* Opaque data type SRC_STATE. */ 00039 typedef struct SRC_STATE_tag SRC_STATE ; 00040 00041 /* SRC_DATA is used to pass data to src_simple() and src_process(). */ 00042 typedef struct 00043 { float *data_in, *data_out ; 00044 00045 long input_frames, output_frames ; 00046 long input_frames_used, output_frames_gen ; 00047 00048 int end_of_input ; 00049 00050 double src_ratio ; 00051 } SRC_DATA ; 00052 00053 /* SRC_CB_DATA is used with callback based API. */ 00054 typedef struct 00055 { long frames ; 00056 float *data_in ; 00057 } SRC_CB_DATA ; 00058 00059 /* 00060 ** User supplied callback function type for use with src_callback_new() 00061 ** and src_callback_read(). First parameter is the same pointer that was 00062 ** passed into src_callback_new(). Second parameter is pointer to a 00063 ** pointer. The user supplied callback function must modify *data to 00064 ** point to the start of the user supplied float array. The user supplied 00065 ** function must return the number of frames that **data points to. 00066 */ 00067 00068 typedef long (*src_callback_t) (void *cb_data, float **data) ; 00069 00070 /* 00071 ** Standard initialisation function : return an anonymous pointer to the 00072 ** internal state of the converter. Choose a converter from the enums below. 00073 ** Error returned in *error. 00074 */ 00075 00076 SRC_STATE* src_new (int converter_type, int channels, int *error) ; 00077 00078 /* 00079 ** Initilisation for callback based API : return an anonymous pointer to the 00080 ** internal state of the converter. Choose a converter from the enums below. 00081 ** The cb_data pointer can point to any data or be set to NULL. Whatever the 00082 ** value, when processing, user supplied function "func" gets called with 00083 ** cb_data as first parameter. 00084 */ 00085 00086 SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels, 00087 int *error, void* cb_data) ; 00088 00089 /* 00090 ** Cleanup all internal allocations. 00091 ** Always returns NULL. 00092 */ 00093 00094 SRC_STATE* src_delete (SRC_STATE *state) ; 00095 00096 /* 00097 ** Standard processing function. 00098 ** Returns non zero on error. 00099 */ 00100 00101 int src_process (SRC_STATE *state, SRC_DATA *data) ; 00102 00103 /* 00104 ** Callback based processing function. Read up to frames worth of data from 00105 ** the converter int *data and return frames read or -1 on error. 00106 */ 00107 long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ; 00108 00109 /* 00110 ** Simple interface for performing a single conversion from input buffer to 00111 ** output buffer at a fixed conversion ratio. 00112 ** Simple interface does not require initialisation as it can only operate on 00113 ** a single buffer worth of audio. 00114 */ 00115 00116 int src_simple (SRC_DATA *data, int converter_type, int channels) ; 00117 00118 /* 00119 ** This library contains a number of different sample rate converters, 00120 ** numbered 0 through N. 00121 ** 00122 ** Return a string giving either a name or a more full description of each 00123 ** sample rate converter or NULL if no sample rate converter exists for 00124 ** the given value. The converters are sequentially numbered from 0 to N. 00125 */ 00126 00127 const char *src_get_name (int converter_type) ; 00128 const char *src_get_description (int converter_type) ; 00129 const char *src_get_version (void) ; 00130 00131 /* 00132 ** Set a new SRC ratio. This allows step responses 00133 ** in the conversion ratio. 00134 ** Returns non zero on error. 00135 */ 00136 00137 int src_set_ratio (SRC_STATE *state, double new_ratio) ; 00138 00139 /* 00140 ** Reset the internal SRC state. 00141 ** Does not modify the quality settings. 00142 ** Does not free any memory allocations. 00143 ** Returns non zero on error. 00144 */ 00145 00146 int src_reset (SRC_STATE *state) ; 00147 00148 /* 00149 ** Return TRUE if ratio is a valid conversion ratio, FALSE 00150 ** otherwise. 00151 */ 00152 00153 int src_is_valid_ratio (double ratio) ; 00154 00155 /* 00156 ** Return an error number. 00157 */ 00158 00159 int src_error (SRC_STATE *state) ; 00160 00161 /* 00162 ** Convert the error number into a string. 00163 */ 00164 const char* src_strerror (int error) ; 00165 00166 /* 00167 ** The following enums can be used to set the interpolator type 00168 ** using the function src_set_converter(). 00169 */ 00170 00171 enum 00172 { 00173 SRC_SINC_BEST_QUALITY = 0, 00174 SRC_SINC_MEDIUM_QUALITY = 1, 00175 SRC_SINC_FASTEST = 2, 00176 SRC_ZERO_ORDER_HOLD = 3, 00177 SRC_LINEAR = 4, 00178 } ; 00179 00180 /* 00181 ** Extra helper functions for converting from short to float and 00182 ** back again. 00183 */ 00184 00185 void src_short_to_float_array (const short *in, float *out, int len) ; 00186 void src_float_to_short_array (const float *in, short *out, int len) ; 00187 00188 void src_int_to_float_array (const int *in, float *out, int len) ; 00189 void src_float_to_int_array (const float *in, int *out, int len) ; 00190 00191 00192 #ifdef __cplusplus 00193 } /* extern "C" */ 00194 #endif /* __cplusplus */ 00195 00196 #endif /* SAMPLERATE_H */ 00197