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
33 #include "engine_vars.h"
35 double beat_buffer[32][80],beat_instant[32],beat_history[32];
36 double *beat_val,*beat_att,*beat_variance;
39 double vol_buffer[80],vol_instant,vol_history;
56 beat_val=(double *)malloc(32*sizeof(double));
57 beat_att=(double *)malloc(32*sizeof(double));
58 beat_variance=(double *)malloc(32*sizeof(double));
75 void getBeatVals(double *vdataL,double *vdataR, double *vol)
86 for ( y=linear*2;y<(linear+8+x)*2;y++)
88 beat_instant[x]+=((vdataL[y]*vdataL[y])+(vdataR[y]*vdataR[y]))*(1.0/(8+x));
89 vol_instant+=((vdataL[y]*vdataL[y])+(vdataR[y]*vdataR[y]))*(1.0/512.0);
94 beat_history[x]-=(beat_buffer[x][beat_buffer_pos])*.0125;
95 beat_buffer[x][beat_buffer_pos]=beat_instant[x];
96 beat_history[x]+=(beat_instant[x])*.0125;
98 beat_val[x]=(beat_instant[x])/(beat_history[x]);
100 beat_att[x]+=(beat_instant[x])/(beat_history[x]);
106 vol_history-=(vol_buffer[beat_buffer_pos])*.0125;
107 vol_buffer[beat_buffer_pos]=vol_instant;
108 vol_history+=(vol_instant)*.0125;
114 mid+=(beat_instant[x]);
115 temp2+=(beat_history[x]);
124 treb+=(beat_instant[x]);
125 temp2+=(beat_history[x]);
127 treb=treb/(1.5*temp2);
128 *vol=vol_instant/(1.5*vol_history);
130 bass=(beat_instant[0])/(1.5*beat_history[0]);
132 treb_att=.6 * treb_att + .4 * treb;
133 mid_att=.6 * mid_att + .4 * mid;
134 bass_att=.6 * bass_att + .4 * bass;
135 //printf("%f %f %f %f\n",bass,mid,treb,*vol);
136 // *vol=(beat_instant[3])/(beat_history[3]);
138 if( beat_buffer_pos>79)beat_buffer_pos=0;
141 void freeBeatDetect()