MFFM Time Scale Modification for Audio Files

Happy user support page :
http://sourceforge.net/donate/index.php?group_id=40316

Copyright 2001 Matt Flax <flatmax at ieee d0t org>

This application stretches and compresses audio without altering the frequency
character of the audio. For reasonable factors, this application will scale
audio without altering signal levels or introducing artifacts (in the ideal
implementation).

The v4.x stream of this project is now targeting embedded operation. The
memory footprint is approaching about 2.5 k Bytes to 7.5 k bytes for a mono
stream of audio and about 5 k bytes to 15 k Bytes for stereo streams. At this
stage the DFT based approach adopted in version 3.x is stable and has excellent
sound quiality even for very fast and very slow time scalings. The code has
been completely re-worked and this has sped up operation to a large degree.

As of Version 3.0, this implementation of WSOLA is now approximatly six times
faster then real time (800MHz CPU with coprocessor).
Operational time on a 24 second stereo sample with a factor of 1.0 :
Linux takes 6 seconds. It is completely stable.
Microsoft takes approximatly the same ammout of time. (Using Cygwin GNU*NIX
translation)

Requirements :

* This program can read alot of file types because of the wrapper to libsndfile :
http://sourceforge.net/projects/mffmlibsndfilew/

* This program requires an installed version of MFFM multimedia time code
handling classes. Try :
http://mffmtimecode.sourceforge.net/

For fast operation (> v 3.* only), you will also require MFFM FFTw C++ wrapper.
Try:
http://mffmfftwrapper.sourceforge.net/

Audio files are read and written using LibSndFile v1 :
http://www.zip.com.au/~erikd/libsndfile/

Finally you require a C++ compiler, try :
http://gcc.gnu.org/install/binaries.html
http://www.cygwin.com (Microsoft users)

MS Windows BINARY users wiil require the file 'cygwin1.dll'. If it is not
shipped with this zip package then please try to find it at Cygwin:
http://www.cygwin.com

My other projects :
http://sourceforge.net/search/?type_of_search=soft&words=mffm

This project's Home Page :
http://mffmtimescale.sourceforge.net

MFFM Time Scale Modification for Audio is 2 things :
a] A compilable program WSOLATest.C which allow you to time stretch and compress
   mono audio files. Audio files are restricted to be mono 16 bit frame sized.
b] A set of 2 header files which are the implementation of [1].

For simple use ....
Type 'make' and compile the program WSOLATest

Run WSOLA like so :
WSOLA inputFile outputFile factor
factor = 0.5 for halving the duration of an audio file
factor = 2.0 for doubling the duration of an audio file
factor = 1.0 for an identical file.

[1]"An overlap-add technique based on waveform similarity (WSOLA)
	for high quality time-scale modification of speech",
	Verhelst, W.; Roelands, M.
	Acoustics, Speech, and Signal Processing, 1993. ICASSP-93.,
	1993 IEEE International Conference on On page(s): 554 - 557 vol.2
	27-30 April 1993 Minneapolis, MN, USA 1993
	Volume: 2
	ISBN: 0-7803-0946-4
	Number of Pages: 5 vol. (652+735+606+559+681)
	References Cited: 4
	INSPEC Accession Number: 4771035
	Abstract:
	A concept of waveform similarity for tackling the problem of 
	time-scale modification of speech is proposed. It is worked 
	out in the context of short-time Fourier transform representations. 
	The resulting WSOLA (waveform-similarity-based synchronized 
	overlap-add) algorithm produces high-quality speech output, 
	is algorithmically and computationally efficient and robust, and 
	allows for online processing with arbitrary time-scaling factors 
	that may be specified in a time-varying fashion and can be chosen 
	over a wide continuous range of values.