www.pudn.com > audioProcessingtoolbox.rar > epdByVol2.m
function [endPoint, volume, zcr, soundSegment] = epdByVol2(y, fs, nbits, plotOpt, epdParam)
% endPointDetect: End point detection based on volume only, where all sound segments are identified.
% Usage: [endPoint, volume, zcr, soundSegment] = endPointDetect03(y, fs, nbits, plotOpt, epdParam)
% Roger Jang, 20041118
if nargin<1, selfdemo; return; end
if nargin<2, fs=8000; end
if nargin<3, nbits=8; end
if nargin<4, plotOpt=0; end
if nargin<5,
epdParam.frameSize = round(fs*480/16000); % fs=16000 ===> frameSize=480;
epdParam.overlap = round(epdParam.frameSize/3*2);
epdParam.zcrRatio = 0.25;
epdParam.volRatio1=10;
epdParam.volRatio2=20;
end
frameSize=epdParam.frameSize;
overlap=epdParam.overlap;
zcrRatio=epdParam.zcrRatio;
if max(y)-min(y)<=2
error('The range of the given y vector is too small! Perhaps it should be converted to integer format...');
end
% ====== Zero adjusted
%y = y-round(mean(y));
% ====== Take frames
framedY = buffer2(y, frameSize, overlap);
frameNum = size(framedY, 2); % Number of frames
frameTime = frame2sampleIndex(1:frameNum, frameSize, overlap)/fs;
% ====== Compute volume/zcr
volume=frame2volume(framedY);
[minVol, index]=min(volume);
shiftAmount=2*max(abs(framedY(:,index))); % 以最小音量之音框中的訊號最大絕對值的兩倍為平移量來進行ZCR
shiiftAmount=max(shiftAmount, 2);
zcr=frame2zcr(framedY, 1, shiftAmount);
% ====== Compute volume/zcr thresholds
volTh1=epdParam.volRatio1*minVol;
volTh2=epdParam.volRatio2*minVol;
maxVol=max(volume);
if volTh2>max(volume)/2 % 避免雜訊太大，導致 volTh2 大於音量最大值的錯誤情況
fprintf('volTh2 too big!\n');
volTh1=maxVol/5;
volTh2=2*volTh1;
end
if maxVol>128*volTh2 % 避免雜訊太小
volTh1=maxVol/128;
volTh2=2*volTh1;
end
zcrTh = max(zcr)*zcrRatio;
% ====== Identify voiced part that's larger than volTh2
voicedIndex = volume>=volTh2;
soundSegment=findSegment(voicedIndex);
% ====== Delete short sound clips
%index = [];
%for i=1:length(soundSegment),
% if (soundSegment(i).end-soundSegment(i).begin)<4
% index = [index, i];
% end
%end
%soundSegment(index) = [];
% ====== Expand end points to volume level1 (lower level)
for i=1:length(soundSegment),
head = soundSegment(i).begin;
while (head-1)>=1 & volume(head-1)>=volTh1,
head=head-1;
end
soundSegment(i).begin = head;
tail = soundSegment(i).end;
while (tail+1)<=length(volume) & volume(tail+1)>=volTh1,
tail=tail+1;
end
soundSegment(i).end = tail;
end
% ====== Delete repeated sound segments
index = [];
for i=1:length(soundSegment)-1,
if soundSegment(i).begin==soundSegment(i+1).begin & soundSegment(i).end==soundSegment(i+1).end,
index=[index, i];
end
end
soundSegment(index) = [];
% ====== Transform sample-point-based index
if length(soundSegment) ~=0,
for i=1:length(soundSegment),
soundSegment(i).beginSample = frame2sampleIndex(soundSegment(i).begin, frameSize, overlap);
soundSegment(i).endSample = min(length(y), frame2sampleIndex(soundSegment(i).end, frameSize, overlap));
soundSegment(i).beginFrame = soundSegment(i).begin;
soundSegment(i).endFrame = soundSegment(i).end;
end
endPoint=[soundSegment(1).beginSample, soundSegment(end).endSample]; % 取頭尾
else
endPoint = [];
end
soundSegment=rmfield(soundSegment, 'begin');
soundSegment=rmfield(soundSegment, 'end');
if plotOpt,
axes1H=subplot(4,1,1);
time=(1:length(y))/fs;
plot(time, y);
axis([min(time), max(time), -2^nbits/2, 2^nbits/2]);
ylabel('Amplitude');
title('Waveform');
% Plot end points
yBound=[-2^nbits/2, 2^nbits/2];
for i=1:length(soundSegment),
line(frame2sampleIndex(soundSegment(i).beginFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'm');
line(frame2sampleIndex( soundSegment(i).endFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'g');
end
axes2H=subplot(4,1,2);
frameTime = frame2sampleIndex(1:frameNum, frameSize, overlap)/fs;
plot(frameTime, volume, '.-');
line([min(frameTime), max(frameTime)], volTh1*[1 1], 'color', 'c');
line([min(frameTime), max(frameTime)], volTh2*[1 1], 'color', 'c');
axis tight
ylabel('Volume');
title('Volume');
% Plot end points
yBound = [min(volume) max(volume)];
for i=1:length(soundSegment),
line(frame2sampleIndex(soundSegment(i).beginFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'm');
line(frame2sampleIndex( soundSegment(i).endFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'g');
end
axes3H=subplot(4,1,3);
plot(frameTime, zcr, '.-');
line([min(frameTime), max(frameTime)], zcrTh*[1 1], 'color', 'c');
axis([min(frameTime), max(frameTime), 0, max(zcr)]);
ylabel('ZCR');
title('Zero crossing rate');
% Plot end points
yBound = [0 max(zcr)];
for i=1:length(soundSegment),
line(frame2sampleIndex(soundSegment(i).beginFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'm');
line(frame2sampleIndex( soundSegment(i).endFrame, frameSize, overlap)/fs*[1,1], yBound, 'color', 'g');
end
axes4H=subplot(4,1,4);
voicedIndex=endPoint(1):endPoint(2);
voicedTime=time(voicedIndex);
voicedY=y(voicedIndex);
voicedH=plot(voicedTime, voicedY);
axis([time(endPoint(1)), time(endPoint(2)), -2^nbits/2, 2^nbits/2]);
ylabel('Amplitude');
title('Voiced waveform');
U.y=y; U.fs=fs; U.nbits=nbits;
U.axes1H=axes1H; U.axes2H=axes2H; U.axes3H=axes3H; U.axes4H=axes4H;
U.voicedIndex=voicedIndex; U.voicedH=voicedH;
U.voicedY=voicedY; U.voicedTime=voicedTime;
set(gcf, 'userData', U);
uicontrol('string', 'Play all', 'callback', 'U=get(gcf, ''userData''); sound(U.y/(2^U.nbits/2), U.fs);');
uicontrol('string', 'Play voiced', 'callback', 'U=get(gcf, ''userData''); sound(U.voicedY/(2^U.nbits/2), U.fs);', 'position', [100, 20, 60, 20]);
% Play the segmented sound
% head = soundSegment(1).beginFrame*(frameSize-overlap);
% tail = min(length(y), soundSegment(end).end*(frameSize-overlap));
% thisY = y(head:tail);
% fprintf('His return to hear the cutted sound %g:', i);
% pause;
% fprintf('\n');
% wavplay(thisY, fs, 'sync');
% fprintf('\n');
end
% ====== Self demo
function selfdemo
waveFile='清華大學資訊系.wav';
waveFile='yankee doodle_不詳_0.wav';
waveFile='vowelMandarin.wav';
plotOpt = 1;
[y, fs, nbits] = wavReadInt(waveFile);
endPoint = feval(mfilename, y, fs, nbits, plotOpt);