1 /*****************************************************************************
2 * beat_detect.c: basic beat detection algorithm
3 *****************************************************************************
4 * Copyright (C) 2004 the VideoLAN team
7 * Authors: Cyril Deguet <asmax@videolan.org>
8 * code from projectM http://xmms-projectm.sourceforge.net
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
23 *****************************************************************************/
28 //Takes sound data from wherever and returns beat detection values
29 //Uses statistical Energy-Based methods. Very simple
31 //Some stuff was taken from Frederic Patin's beat-detection article, you'll find it online
35 #include "engine_vars.h"
37 double beat_buffer[32][80],beat_instant[32],beat_history[32];
38 double *beat_val,*beat_att,*beat_variance;
41 double vol_buffer[80],vol_instant,vol_history;
58 beat_val=(double *)malloc(32*sizeof(double));
59 beat_att=(double *)malloc(32*sizeof(double));
60 beat_variance=(double *)malloc(32*sizeof(double));
77 void getBeatVals(double *vdataL,double *vdataR, double *vol)
88 for ( y=linear*2;y<(linear+8+x)*2;y++)
90 beat_instant[x]+=((vdataL[y]*vdataL[y])+(vdataR[y]*vdataR[y]))*(1.0/(8+x));
91 vol_instant+=((vdataL[y]*vdataL[y])+(vdataR[y]*vdataR[y]))*(1.0/512.0);
96 beat_history[x]-=(beat_buffer[x][beat_buffer_pos])*.0125;
97 beat_buffer[x][beat_buffer_pos]=beat_instant[x];
98 beat_history[x]+=(beat_instant[x])*.0125;
100 beat_val[x]=(beat_instant[x])/(beat_history[x]);
102 beat_att[x]+=(beat_instant[x])/(beat_history[x]);
108 vol_history-=(vol_buffer[beat_buffer_pos])*.0125;
109 vol_buffer[beat_buffer_pos]=vol_instant;
110 vol_history+=(vol_instant)*.0125;
116 mid+=(beat_instant[x]);
117 temp2+=(beat_history[x]);
126 treb+=(beat_instant[x]);
127 temp2+=(beat_history[x]);
129 treb=treb/(1.5*temp2);
130 *vol=vol_instant/(1.5*vol_history);
132 bass=(beat_instant[0])/(1.5*beat_history[0]);
134 treb_att=.6 * treb_att + .4 * treb;
135 mid_att=.6 * mid_att + .4 * mid;
136 bass_att=.6 * bass_att + .4 * bass;
137 //printf("%f %f %f %f\n",bass,mid,treb,*vol);
138 // *vol=(beat_instant[3])/(beat_history[3]);
140 if( beat_buffer_pos>79)beat_buffer_pos=0;
143 void freeBeatDetect()