.TH zresample 1  "May 2010" "version 0.0.1" "USER COMMANDS"
.SH NAME
zresample \- resample and change sample format of audio files
.SH SYNOPSIS
.B zresample
[options] input-file output-file
.SH DESCRIPTION
.B zresample
copies an audio file, changing the sample rate and/or the
sample format. For 16-bit output it can also dither the
audio signal. Input can be any audio file readable by the
libsndfile library. The output file type is either WAV, WAVEX,
CAF, AIFF or FLAC.
.SH OPTIONS
.TP
.B --help
Display a short help text.
.TP
.B --rate sample-rate
Set the output sample rate.
.B Zresample
uses the zita-resampler library which means that not all 
combinations of input/output sample rate will be accepted.
The resample ratio must be a reducable to a fraction
.B a/b
with both
.B a
and
.B b
less than or equal to 1000. 
.TP
.B --gain gain
Gain in dB, default zero.
.SS Output file type
.TP
.B --wav
Produce a WAV file, or for more than 2 channels, a WAVEX file.
This is the default.  
.TP
.B --amb
Produce a WAVEX file with the Ambisonic GUID. Such files should
have the
.B .amb
filename extension.
.TP
.B --caf
Produce a Core Audio file.
.TP
.B --aiff
Produce an AIFF file.
.TP
.B --flac
Produce a FLAC file.
.SS Output sample format
.TP
.B --16bit
Output sample format is signed 16-bit. This option also
enables the use of dithering, described below.
.TP
.B --24bit
Output sample format is 24-bit. This is the default.
.TP
.B --float
Output sample format is 32-bit floating point.
.SS Dithering
.TP
.B --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.
.TP
.B --tri
Add filtered noise with a triangular distribution. Compared to the
rectangular dither this reduces the noise density in the lower
frequency range.
.TP
.B --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.
.SS Timing
.TP
.B --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. 
.SH EXIT STATUS
Zero in case there are no errors, non-zero otherwise.
.SH AUTHOR
Fons Adriaensen (fons (at) linuxaudio.org)