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     double a0_lo;
  55     double b1_lo;
  56
  57     /* Highboost IIR filter coefficients */
  58     double a0_hi;
  59     double a1_hi;
  60     double b1_hi;
  61
  62     /* Global gain against overloading */
  63     float gain;
  64
  65     /* Buffer of last filtered sample.
  66      * [0] - first channel, [1] - second channel
  67      */
  68     struct t_last_sample {
  69         double asis[2];
  70         double lo[2];
  71         double hi[2];
  72     } last_sample;
  73 };
  74
  75 /* Clear buffers and set new coefficients with new crossfeed level value.
  76  * level - crossfeed level of *LEVEL values.
  77  */
  78 void bs2b_set_level(struct bs2b *bs2b, int level);
  79
  80 /* Return current crossfeed level value */
  81 int bs2b_get_level(struct bs2b *bs2b);
  82
  83 /* Clear buffers and set new coefficients with new sample rate value.
  84  * srate - sample rate by Hz.
  85  */
  86 void bs2b_set_srate(struct bs2b *bs2b, int srate);
  87
  88 /* Return current sample rate value */
  89 int bs2b_get_srate(struct bs2b *bs2b);
  90
  91 /* Clear buffer */
  92 void bs2b_clear(struct bs2b *bs2b);
  93
  94 /* Crossfeeds one stereo sample that are pointed by sample.
  95  * [0] - first channel, [1] - second channel.
  96  * Returns crossfided samle by sample pointer.
  97  */
  98
  99 /* sample poits to floats */
 100 void bs2b_cross_feed(struct bs2b *bs2b, float *sample);
 101
 102 #ifdef __cplusplus
 103 }    /* extern "C" */
 104 #endif /* __cplusplus */
 105
 106 #endif /* BS2B_H */