vorbis_psy.h

00001 /* Copyright (C) 2005 Jean-Marc Valin, CSIRO, Christopher Montgomery
00002    File: vorbis_psy.h
00003 
00004    Redistribution and use in source and binary forms, with or without
00005    modification, are permitted provided that the following conditions
00006    are met:
00007    
00008    - Redistributions of source code must retain the above copyright
00009    notice, this list of conditions and the following disclaimer.
00010    
00011    - Redistributions in binary form must reproduce the above copyright
00012    notice, this list of conditions and the following disclaimer in the
00013    documentation and/or other materials provided with the distribution.
00014    
00015    - Neither the name of the Xiph.org Foundation nor the names of its
00016    contributors may be used to endorse or promote products derived from
00017    this software without specific prior written permission.
00018    
00019    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00020    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00021    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00022    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00023    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00024    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00025    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00026    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00027    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00028    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00029    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00030 */
00031 
00032 #ifndef VORBIS_PSY_H
00033 #define VORBIS_PSY_H
00034 
00035 #ifdef VORBIS_PSYCHO
00036 
00037 #include "smallft.h"
00038 #define P_BANDS 17      /* 62Hz to 16kHz */
00039 #define NOISE_COMPAND_LEVELS 40
00040 
00041 
00042 #define todB(x)   ((x)==0?-400.f:log((x)*(x))*4.34294480f)
00043 #define fromdB(x) (exp((x)*.11512925f))  
00044 
00045 /* The bark scale equations are approximations, since the original
00046    table was somewhat hand rolled.  The below are chosen to have the
00047    best possible fit to the rolled tables, thus their somewhat odd
00048    appearance (these are more accurate and over a longer range than
00049    the oft-quoted bark equations found in the texts I have).  The
00050    approximations are valid from 0 - 30kHz (nyquist) or so.
00051 
00052    all f in Hz, z in Bark */
00053 
00054 #define toBARK(n)   (13.1f*atan(.00074f*(n))+2.24f*atan((n)*(n)*1.85e-8f)+1e-4f*(n))
00055 #define fromBARK(z) (102.f*(z)-2.f*pow(z,2.f)+.4f*pow(z,3.f)+pow(1.46f,z)-1.f)
00056 
00057 /* Frequency to octave.  We arbitrarily declare 63.5 Hz to be octave
00058    0.0 */
00059 
00060 #define toOC(n)     (log(n)*1.442695f-5.965784f)
00061 #define fromOC(o)   (exp(((o)+5.965784f)*.693147f))
00062 
00063 
00064 typedef struct {
00065 
00066   float noisewindowlo;
00067   float noisewindowhi;
00068   int   noisewindowlomin;
00069   int   noisewindowhimin;
00070   int   noisewindowfixed;
00071   float noiseoff[P_BANDS];
00072   float noisecompand[NOISE_COMPAND_LEVELS];
00073 
00074 } VorbisPsyInfo;
00075 
00076 
00077 
00078 typedef struct {
00079   int n;
00080   int rate;
00081   struct drft_lookup lookup;
00082   VorbisPsyInfo *vi;
00083 
00084   float *window;
00085   float *noiseoffset;
00086   long  *bark;
00087 
00088 } VorbisPsy;
00089 
00090 
00091 VorbisPsy *vorbis_psy_init(int rate, int size);
00092 void vorbis_psy_destroy(VorbisPsy *psy);
00093 void compute_curve(VorbisPsy *psy, float *audio, float *curve);
00094 void curve_to_lpc(VorbisPsy *psy, float *curve, float *awk1, float *awk2, int ord);
00095 
00096 #endif
00097 #endif