matthiasm@8: function [timesig,three_energy,four_energy] = findmeter_mm(acf,period,thresh);
matthiasm@8: 
matthiasm@8: % a simple enegy test with current period value, where energy is evaluated
matthiasm@8: % at small regions at double and four times the period, to be compared with
matthiasm@8: % energy at 3 and 6 times the beat period, to decide if the time signature
matthiasm@8: % of the current frame is duple or triple.
matthiasm@8: 
matthiasm@8: if nargin<3
matthiasm@8: 	thresh = 0;
matthiasm@8: %default state
matthiasm@8: end
matthiasm@8: 
matthiasm@8: 
matthiasm@8: acf = acf/sum(acf);
matthiasm@8: 
matthiasm@8: period = round(period);
matthiasm@8: 
matthiasm@8: sw= 2;
matthiasm@8: 
matthiasm@8: 
matthiasm@8: %  % new approach - LESS GOOD than the old approach
matthiasm@8: %  
matthiasm@8: %  numperiods = floor(length(acf)/period);
matthiasm@8: %  num4multiples = floor(numperiods/4);
matthiasm@8: %  %  % just check we haven't gone over the end of the acf
matthiasm@8: %  num4multiples = num4multiples- double((period*num4multiples*4+sw) > length(acf));
matthiasm@8: %  
matthiasm@8: %  % initialize;
matthiasm@8: %  three_energy = 0;
matthiasm@8: %  four_energy = 0;
matthiasm@8: %  
matthiasm@8: %  for i=1:length(num4multiples)
matthiasm@8: %  
matthiasm@8: %  	three_energy = three_energy + sum(acf(3*i*period-sw:1:3*i*period+sw));
matthiasm@8: %  	four_energy = four_energy + sum(acf(4*i*period-sw:1:4*i*period+sw));
matthiasm@8: %  
matthiasm@8: %  end
matthiasm@8: 
matthiasm@8: 
matthiasm@8: % old approach... 
matthiasm@8: 
matthiasm@8: if(length(acf)<6*period+sw)
matthiasm@8:     
matthiasm@8: 
matthiasm@8:     three_energy = sum(acf(3*period-sw:1:3*period+sw));
matthiasm@8: 
matthiasm@8:     four_energy = sum(acf(4*period-sw:1:4*period+sw));
matthiasm@8: 
matthiasm@8: else
matthiasm@8: 
matthiasm@8:     three_energy = sum(acf(3*period-sw:1:3*period+sw)) + sum(acf(6*period-sw:1:6*period+sw));
matthiasm@8: 
matthiasm@8:     four_energy = sum(acf(4*period-sw:1:4*period+sw)) + sum(acf(2*period-sw:1:2*period+sw));
matthiasm@8: 
matthiasm@8: end
matthiasm@8: 
matthiasm@8: 
matthiasm@8: if ( (four_energy - three_energy) >= thresh )
matthiasm@8:     timesig = 4;
matthiasm@8: else
matthiasm@8:     timesig = 3;
matthiasm@8: end