NAME

       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 given directly or expressed in cents, without
       changing  the  nominal  sample  rate.   The result is to change the musical pitch and length of the file.
       Input can be any audio file readable by the libsndfile library.  The output  file  type  is  either  WAV,
       WAVEX, CAF, AIFF or FLAC.

OPTIONS

       --help Display a short help text.

       --ratio pitch ratio
              The accepted range is 0.5 to 2.0. The useful range in practice will be smaller.

       --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.

       --aiff Produce an AIFF file.

       --flac Produce a FLAC 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)

version 0.0.1                                       Sept 2012                                         zretune(1)