windows/samplerate.h

   1 /*
   2 ** Copyright (C) 2002-2008 Erik de Castro Lopo <erikd@mega-nerd.com>
   3 **
   4 ** This program is free software; you can redistribute it and/or modify
   5 ** it under the terms of the GNU General Public License as published by
   6 ** the Free Software Foundation; either version 2 of the License, or
   7 ** (at your option) any later version.
   8 **
   9 ** This program is distributed in the hope that it will be useful,
  10 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 ** GNU General Public License for more details.
  13 **
  14 ** You should have received a copy of the GNU General Public License
  15 ** along with this program; if not, write to the Free Software
  16 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  17 */
  18
  19 /*
  20 ** This code is part of Secret Rabibt Code aka libsamplerate. A commercial
  21 ** use license for this code is available, please see:
  22 **              http://www.mega-nerd.com/SRC/procedure.html
  23 */
  24
  25 /*
  26 ** API documentation is available here:
  27 **     http://www.mega-nerd.com/SRC/api.html
  28 */
  29
  30 #ifndef SAMPLERATE_H
  31 #define SAMPLERATE_H
  32
  33 #ifdef __cplusplus
  34 extern "C" {
  35 #endif  /* __cplusplus */
  36
  37
  38 /* Opaque data type SRC_STATE. */
  39 typedef struct SRC_STATE_tag SRC_STATE ;
  40
  41 /* SRC_DATA is used to pass data to src_simple() and src_process(). */
  42 typedef struct
  43 {       float   *data_in, *data_out ;
  44
  45         long    input_frames, output_frames ;
  46         long    input_frames_used, output_frames_gen ;
  47
  48         int             end_of_input ;
  49
  50         double  src_ratio ;
  51 } SRC_DATA ;
  52
  53 /* SRC_CB_DATA is used with callback based API. */
  54 typedef struct
  55 {       long    frames ;
  56         float   *data_in ;
  57 } SRC_CB_DATA ;
  58
  59 /*
  60 ** User supplied callback function type for use with src_callback_new()
  61 ** and src_callback_read(). First parameter is the same pointer that was
  62 ** passed into src_callback_new(). Second parameter is pointer to a
  63 ** pointer. The user supplied callback function must modify *data to
  64 ** point to the start of the user supplied float array. The user supplied
  65 ** function must return the number of frames that **data points to.
  66 */
  67
  68 typedef long (*src_callback_t) (void *cb_data, float **data) ;
  69
  70 /*
  71 **      Standard initialisation function : return an anonymous pointer to the
  72 **      internal state of the converter. Choose a converter from the enums below.
  73 **      Error returned in *error.
  74 */
  75
  76 SRC_STATE* src_new (int converter_type, int channels, int *error) ;
  77
  78 /*
  79 **      Initialisation for callback based API : return an anonymous pointer to the
  80 **      internal state of the converter. Choose a converter from the enums below.
  81 **      The cb_data pointer can point to any data or be set to NULL. Whatever the
  82 **      value, when processing, user supplied function "func" gets called with
  83 **      cb_data as first parameter.
  84 */
  85
  86 SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels,
  87                                 int *error, void* cb_data) ;
  88
  89 /*
  90 **      Cleanup all internal allocations.
  91 **      Always returns NULL.
  92 */
  93
  94 SRC_STATE* src_delete (SRC_STATE *state) ;
  95
  96 /*
  97 **      Standard processing function.
  98 **      Returns non zero on error.
  99 */
 100
 101 int src_process (SRC_STATE *state, SRC_DATA *data) ;
 102
 103 /*
 104 **      Callback based processing function. Read up to frames worth of data from
 105 **      the converter int *data and return frames read or -1 on error.
 106 */
 107 long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ;
 108
 109 /*
 110 **      Simple interface for performing a single conversion from input buffer to
 111 **      output buffer at a fixed conversion ratio.
 112 **      Simple interface does not require initialisation as it can only operate on
 113 **      a single buffer worth of audio.
 114 */
 115
 116 int src_simple (SRC_DATA *data, int converter_type, int channels) ;
 117
 118 /*
 119 ** This library contains a number of different sample rate converters,
 120 ** numbered 0 through N.
 121 **
 122 ** Return a string giving either a name or a more full description of each
 123 ** sample rate converter or NULL if no sample rate converter exists for
 124 ** the given value. The converters are sequentially numbered from 0 to N.
 125 */
 126
 127 const char *src_get_name (int converter_type) ;
 128 const char *src_get_description (int converter_type) ;
 129 const char *src_get_version (void) ;
 130
 131 /*
 132 **      Set a new SRC ratio. This allows step responses
 133 **      in the conversion ratio.
 134 **      Returns non zero on error.
 135 */
 136
 137 int src_set_ratio (SRC_STATE *state, double new_ratio) ;
 138
 139 /*
 140 **      Reset the internal SRC state.
 141 **      Does not modify the quality settings.
 142 **      Does not free any memory allocations.
 143 **      Returns non zero on error.
 144 */
 145
 146 int src_reset (SRC_STATE *state) ;
 147
 148 /*
 149 ** Return TRUE if ratio is a valid conversion ratio, FALSE
 150 ** otherwise.
 151 */
 152
 153 int src_is_valid_ratio (double ratio) ;
 154
 155 /*
 156 **      Return an error number.
 157 */
 158
 159 int src_error (SRC_STATE *state) ;
 160
 161 /*
 162 **      Convert the error number into a string.
 163 */
 164 const char* src_strerror (int error) ;
 165
 166 /*
 167 ** The following enums can be used to set the interpolator type
 168 ** using the function src_set_converter().
 169 */
 170
 171 enum
 172 {
 173         SRC_SINC_BEST_QUALITY           = 0,
 174         SRC_SINC_MEDIUM_QUALITY         = 1,
 175         SRC_SINC_FASTEST                        = 2,
 176         SRC_ZERO_ORDER_HOLD                     = 3,
 177         SRC_LINEAR                                      = 4,
 178 } ;
 179
 180 /*
 181 ** Extra helper functions for converting from short to float and
 182 ** back again.
 183 */
 184
 185 void src_short_to_float_array (const short *in, float *out, int len) ;
 186 void src_float_to_short_array (const float *in, short *out, int len) ;
 187
 188 void src_int_to_float_array (const int *in, float *out, int len) ;
 189 void src_float_to_int_array (const float *in, int *out, int len) ;
 190
 191
 192 #ifdef __cplusplus
 193 }               /* extern "C" */
 194 #endif  /* __cplusplus */
 195
 196 #endif  /* SAMPLERATE_H */
 197