www.pudn.com > audioProcessingtoolbox.rar > frame2smdf.m

function out=frame2smdf(frame, maxShift, method, plotOpt) 
% frame2smdf: SMDF (sum of magnitude difference function) of a given frame (primarily for pitch tracking) 
%	Usage: out=frame2smdf(frame, maxShift, method, plotOpt); 
%		maxShift: no. of shift operations, which is equal to the length of the output vector 
%		method: 1 for using the whole frame for shifting 
%			2 for using the whole frame for shifting, but normalize the sum by it's overlap area 
%			3 for using frame(1:frameSize-maxShift) for shifting 
%			4 for using frame(1:maxShift) for shifting 
%		plotOpt: 0 for no plot, 1 for plotting the frame and SMDF output 
%		out: the returned SMDF vector 
% 
%	See also FRAME2ACF. 
 
%	Roger Jang 20020404, 20041013, 20060313 
 
if nargin<1, selfdemo; return; end 
if nargin<2, maxShift=length(frame); end 
if nargin<3, method=1; end 
if nargin<4, plotOpt=0; end 
 
frameSize=length(frame); 
out=zeros(maxShift, 1); 
switch method 
	case 1		% moving base = whole frame 
		for i=2:maxShift 
			out(i) = sum(abs(frame(1:frameSize-i+1)-frame(i:frameSize))); 
		end 
	case 2		% moving base = whole frame, but normalized by the overlap area 
		for i=2:maxShift 
			out(i) = sum(abs(frame(1:frameSize-i+1)-frame(i:frameSize))); 
			out(i) = out(i)/(frameSize-i+1);		% ¨DĄ­§ˇ 
		end 
	case 3		% moving base = frame(1:frameSize-maxShift) 
		for i=2:maxShift 
			out(i) = sum(abs(frame(1:frameSize-maxShift)-frame(i:frameSize-maxShift+i-1))); 
		end 
	case 4		% moving base = frame(1:maxShift), assuming maxShift<=frameSize/2 
		for i=2:maxShift 
			out(i) = sum(abs(frame(1:maxShift)-frame(i:maxShift+i-1))); 
		end 
	otherwise 
		error('Unknown method!'); 
end 
 
if plotOpt 
	subplot(2,1,1); 
	plot(frame, '.-'); 
	set(gca, 'xlim', [-inf inf]); 
	title('Input frame'); 
	subplot(2,1,2); 
	plot(out, '.-'); 
	set(gca, 'xlim', [-inf inf]); 
	title(sprintf('SMDF vector (method = %d)', method)); 
end 
 
% ====== Self demo 
function selfdemo 
waveFile='greenOil.wav'; 
[y, fs, nbits]=wavReadInt(waveFile); 
framedY=buffer2(y, 256, 0); 
frame=framedY(:, 250); 
subplot(4,1,1); 
plot(frame, '.-'); 
title('Input frame'); axis tight 
subplot(4,1,2); 
method=1; out=feval(mfilename, frame, 256, method); 
plot(out, '.-'); title('method=1'); axis tight 
subplot(4,1,3); 
method=2; out=feval(mfilename, frame, 256, method); 
plot(out, '.-'); title('method=2'); axis tight 
subplot(4,1,4); 
method=3; out=feval(mfilename, frame, 128, method); 
plot(out, '.-'); title('method=3'); axis tight