apps/codecs/libspeex/vorbis_psy.h

   1 /* Copyright (C) 2005 Jean-Marc Valin, CSIRO, Christopher Montgomery
   2    File: vorbis_psy.h
   3
   4    Redistribution and use in source and binary forms, with or without
   5    modification, are permitted provided that the following conditions
   6    are met:
   7
   8    - Redistributions of source code must retain the above copyright
   9    notice, this list of conditions and the following disclaimer.
  10
  11    - Redistributions in binary form must reproduce the above copyright
  12    notice, this list of conditions and the following disclaimer in the
  13    documentation and/or other materials provided with the distribution.
  14
  15    - Neither the name of the Xiph.org Foundation nor the names of its
  16    contributors may be used to endorse or promote products derived from
  17    this software without specific prior written permission.
  18
  19    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
  23    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  24    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  25    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  26    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  27    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  28    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  29    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30 */
  31
  32 #ifndef VORBIS_PSY_H
  33 #define VORBIS_PSY_H
  34
  35 #ifdef VORBIS_PSYCHO
  36
  37 #include "smallft.h"
  38 #define P_BANDS 17      /* 62Hz to 16kHz */
  39 #define NOISE_COMPAND_LEVELS 40
  40
  41
  42 #define todB(x)   ((x)>1e-13?log((x)*(x))*4.34294480f:-30)
  43 #define fromdB(x) (exp((x)*.11512925f))
  44
  45 /* The bark scale equations are approximations, since the original
  46    table was somewhat hand rolled.  The below are chosen to have the
  47    best possible fit to the rolled tables, thus their somewhat odd
  48    appearance (these are more accurate and over a longer range than
  49    the oft-quoted bark equations found in the texts I have).  The
  50    approximations are valid from 0 - 30kHz (nyquist) or so.
  51
  52    all f in Hz, z in Bark */
  53
  54 #define toBARK(n)   (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n))
  55 #define fromBARK(z) (102.f*(z)-2.f*pow(z,2.f)+.4f*pow(z,3.f)+pow(1.46f,z)-1.f)
  56
  57 /* Frequency to octave.  We arbitrarily declare 63.5 Hz to be octave
  58    0.0 */
  59
  60 #define toOC(n)     (log(n)*1.442695f-5.965784f)
  61 #define fromOC(o)   (exp(((o)+5.965784f)*.693147f))
  62
  63
  64 typedef struct {
  65
  66   float noisewindowlo;
  67   float noisewindowhi;
  68   int   noisewindowlomin;
  69   int   noisewindowhimin;
  70   int   noisewindowfixed;
  71   float noiseoff[P_BANDS];
  72   float noisecompand[NOISE_COMPAND_LEVELS];
  73
  74 } VorbisPsyInfo;
  75
  76
  77
  78 typedef struct {
  79   int n;
  80   int rate;
  81   struct drft_lookup lookup;
  82   VorbisPsyInfo *vi;
  83
  84   float *window;
  85   float *noiseoffset;
  86   long  *bark;
  87
  88 } VorbisPsy;
  89
  90
  91 VorbisPsy *vorbis_psy_init(int rate, int size);
  92 void vorbis_psy_destroy(VorbisPsy *psy);
  93 void compute_curve(VorbisPsy *psy, float *audio, float *curve);
  94 void curve_to_lpc(VorbisPsy *psy, float *curve, float *awk1, float *awk2, int ord);
  95
  96 #endif
  97 #endif