Mauch MIREX 2010

function [timesig,three_energy,four_energy] = findmeter_mm(acf,period,thresh);

% a simple enegy test with current period value, where energy is evaluated

% at small regions at double and four times the period, to be compared with

% energy at 3 and 6 times the beat period, to decide if the time signature

% of the current frame is duple or triple.

if nargin<3

	thresh = 0;

%default state

end

acf = acf/sum(acf);

period = round(period);

sw= 2;

%  % new approach - LESS GOOD than the old approach

%  

%  numperiods = floor(length(acf)/period);

%  num4multiples = floor(numperiods/4);

%  %  % just check we haven't gone over the end of the acf

%  num4multiples = num4multiples- double((period*num4multiples*4+sw) > length(acf));

%  

%  % initialize;

%  three_energy = 0;

%  four_energy = 0;

%  

%  for i=1:length(num4multiples)

%  

%  	three_energy = three_energy + sum(acf(3*i*period-sw:1:3*i*period+sw));

%  	four_energy = four_energy + sum(acf(4*i*period-sw:1:4*i*period+sw));

%  

%  end

% old approach... 

if(length(acf)<6*period+sw)

    three_energy = sum(acf(3*period-sw:1:3*period+sw));

    four_energy = sum(acf(4*period-sw:1:4*period+sw));

else

    three_energy = sum(acf(3*period-sw:1:3*period+sw)) + sum(acf(6*period-sw:1:6*period+sw));

    four_energy = sum(acf(4*period-sw:1:4*period+sw)) + sum(acf(2*period-sw:1:2*period+sw));

end

if ( (four_energy - three_energy) >= thresh )

    timesig = 4;

else

    timesig = 3;

end