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 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.

       --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)