Rubber Band
An audio time-stretching and pitch-shifting library and utility program.
Copyright 2008 Chris Cannam. Distributed under the GNU General Public License.

Usage: rubberband [options] <infile.wav> <outfile.wav>

You must specify at least one of the following time and pitch ratio options.

-t<X>, --time <X> Stretch to X times original duration, or
-T<X>, --tempo <X> Change tempo by multiple X (same as --time 1/X), or
-T<X>, --tempo <X>:<Y> Change tempo from X to Y (same as --time X/Y), or
-D<X>, --duration <X> Stretch or squash to make output file X seconds long

-p<X>, --pitch <X> Raise pitch by X semitones, or
-f<X>, --frequency <X> Change frequency by multiple X

The following options provide a simple way to adjust the sound. See below
for more details.

-c<N>, --crisp <N> Crispness (N = 0,1,2,3,4,5); default 4 (see below)
-F, --formant Enable formant preservation when pitch shifting

The remaining options fine-tune the processing mode and stretch algorithm.
These are mostly included for test purposes; the default settings and standard
crispness parameter are intended to provide the best sounding set of options
for most situations. The default is to use none of these options.

-P, --precise Aim for minimal time distortion (implied by -R)
-R, --realtime Select realtime mode (implies -P --no-threads)
--no-threads No extra threads regardless of CPU and channel count
--threads Assume multi-CPU even if only one CPU is identified
--no-transients Disable phase resynchronisation at transients
--bl-transients Band-limit phase resync to extreme frequencies
--no-lamination Disable phase lamination
--window-long Use longer processing window (actual size may vary)
--window-short Use shorter processing window
--pitch-hq In RT mode, use a slower, higher quality pitch shift

-d<N>, --debug <N> Select debug level (N = 0,1,2,3); default 0, full 3
(N.B. debug level 3 includes audible ticks in output)
-q, --quiet Suppress progress output

-V, --version Show version number and exit
-h, --help Show this help

"Crispness" levels:
-c 0 equivalent to --no-transients --no-lamination --window-long
-c 1 equivalent to --no-transients --no-lamination
-c 2 equivalent to --no-transients
-c 3 equivalent to --bl-transients
-c 4 default processing options
-c 5 equivalent to --no-lamination --window-short (may be good for drums)