NAME¶
zita-retune - resample an audio file in order to change its pitch
SYNOPSIS¶
zita-retune <options> <input file> <output
file>.
DESCRIPTION¶
zita-retune 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 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.
- --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.
SEE ALSO¶
Some examples of dithering are available here:
http://www.kokkinizita.net/linuxaudio/dithering.html
AUTHOR¶
zita-retune was written by Fons Adriaensen <fons@kokkinizita.net>.
This manual page was written by Jaromír Mikeš
<mira.mikes@seznam.cz> for the Debian project (but may be used by
others).