% 2009-01-20-tsm.diary
% Time-scale modification examples
% see http://www.ee.columbia.edu/~dpwe/e6820/matlab/ for the functions used.
% 2008-01-24 dpwe@ee.columbia.edu

% Load example soundfile
[d,sr]=wavread('mpgr1_sx419-8k.wav');
soundsc(d,sr)

% Simply 'slow it down'
soundsc(resample(d,3,2),sr)

% Check usage options for time-domain time-scale modification
help solafs

% Make a longer version
dsl = solafs(d',.67,400,200,100);
soundsc(dsl,sr)

% Compare to SOLAFS with a narrow constraint on window adjustment
dsl2 = solafs(d',.67,400,200,5);
soundsc(dsl2,sr)

% Check usage of STFT-based TSM
help pvoc

% Stretch the spectrogram, correct the phase
dpv = pvoc(d,0.67,256);
soundsc(dpv,sr)

% What if we do this on a wideband spectrogram (short window)?
dpv2 = pvoc(d,0.67, 64);
soundsc(dpv2,sr)
% It lowers the pitch, but not like slowing down...
soundsc(resample(d,3,2),sr)