OpenAL32/Include/bs2b.h

   1 /*-
   2  * Copyright (c) 2005 Boris Mikhaylov
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  18  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
  19  * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  20  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  21  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #ifndef BS2B_H
  25 #define BS2B_H
  26
  27 /* Number of crossfeed levels */
  28 #define BS2B_CLEVELS           3
  29
  30 /* Normal crossfeed levels */
  31 #define BS2B_HIGH_CLEVEL       3
  32 #define BS2B_MIDDLE_CLEVEL     2
  33 #define BS2B_LOW_CLEVEL        1
  34
  35 /* Easy crossfeed levels */
  36 #define BS2B_HIGH_ECLEVEL      BS2B_HIGH_CLEVEL    + BS2B_CLEVELS
  37 #define BS2B_MIDDLE_ECLEVEL    BS2B_MIDDLE_CLEVEL  + BS2B_CLEVELS
  38 #define BS2B_LOW_ECLEVEL       BS2B_LOW_CLEVEL     + BS2B_CLEVELS
  39
  40 /* Default crossfeed levels */
  41 #define BS2B_DEFAULT_CLEVEL    BS2B_HIGH_ECLEVEL
  42 /* Default sample rate (Hz) */
  43 #define BS2B_DEFAULT_SRATE     44100
  44
  45 #ifdef __cplusplus
  46 extern "C" {
  47 #endif /* __cplusplus */
  48
  49 struct bs2b {
  50     int level;  /* Crossfeed level */
  51     int srate;   /* Sample rate (Hz) */
  52
  53     /* Lowpass IIR filter coefficients */
  54     float a0_lo;
  55     float b1_lo;
  56
  57     /* Highboost IIR filter coefficients */
  58     float a0_hi;
  59     float a1_hi;
  60     float b1_hi;
  61
  62     /* Buffer of last filtered sample.
  63      * [0] - first channel, [1] - second channel
  64      */
  65     struct t_last_sample {
  66         float asis;
  67         float lo;
  68         float hi;
  69     } last_sample[2];
  70 };
  71
  72 /* Clear buffers and set new coefficients with new crossfeed level and sample
  73  * rate values.
  74  * level - crossfeed level of *LEVEL values.
  75  * srate - sample rate by Hz.
  76  */
  77 void bs2b_set_params(struct bs2b *bs2b, int level, int srate);
  78
  79 /* Return current crossfeed level value */
  80 int bs2b_get_level(struct bs2b *bs2b);
  81
  82 /* Return current sample rate value */
  83 int bs2b_get_srate(struct bs2b *bs2b);
  84
  85 /* Clear buffer */
  86 void bs2b_clear(struct bs2b *bs2b);
  87
  88 void bs2b_cross_feed(struct bs2b *bs2b, float *restrict Left, float *restrict Right, int SamplesToDo);
  89
  90 #ifdef __cplusplus
  91 }    /* extern "C" */
  92 #endif /* __cplusplus */
  93
  94 #endif /* BS2B_H */