zretune man page

zretune — resample an audio file in order to change its pitch

Synopsis

zretune [options] input-file output-file

Description

zretune resamples an audio file by a the inverse of a ratio expressed in cents, without changing the nominal sample rate. The result is to change the musical pitch and lenght of the file. Input can be any audio file readable by the libsndfile library. The output file type is either WAV or CAF.

Options

--help

Display a short help text.

--cent pitch change in cents

The number of cents by which the pitch is changed. The accepted range is +/- 1200 cents, the useful range in practice will be  something like +/- 100 cents.

Output file type

--wav

Produce a WAV file, or for more than 2 channels, a WAVEX file. This is the default.  

--amb

Produce a WAVEX file with the Ambisonic GUID. Such files should have the .amb filename extension.

--caf

Produce a Core Audio file.

Output sample format

--16bit

Output sample format is signed 16-bit. This option also enables the use of dithering, described below.

--24bit

Output sample format is 24-bit. This is the default.

--float

Output sample format is 32-bit floating point.

Dithering

--rec

Add white dithering noise with a rectangular distribution. This is the best option if the output data is going to processed again, but in that case it would be advisable to use 24-bit or float.

--tri

Add filtered noise with a triangular distribution. Compared to the rectangular dither this reduces the noise density in the lower frequency range.

--lips

This uses the optimal error feedback filter described by  Stanley Lipschitz. This is recommended is the output is the final distribution format, e.g. for a CD.

Timing

--pad

Insert zero valued input samples at the start and end so that the output includes the full symmetric filter response even for the first and last samples.

Exit Status

Zero in case there are no errors, non-zero otherwise.

Author

Fons Adriaensen (fons (at) linuxaudio.org)

Info

Sect 2012 version 0.0.1 USER COMMANDS