squniform.1

spiht for linux this is used to decod and encode vedio i wich all enjoy

.TH SQUNIFORM 1 "QCCPACK" ""
.SH NAME
squniform \- make uniform scalar quantizer
.SH SYNOPSIS
.B squniform
.RB "[\|" \-max
.IR  max\_value "\|]"
.RB "[\|" \-min
.IR min\_value "\|]"
.RB "[\|" \-u 
.IR u "\|]"
.RB "[\|" \-A
.IR A "\|]"
.RB "[\|" \-nl
.IR num\_levels "\|]"
.RB "[\|" \-q
.IR stepsize "\|]"
.RB "[\|" \-d
.IR deadzone "\|]"
.I quantizer\_file
.SH OPTIONS
.TP
.BI \-max " max\_value"
Float. Maximum value of the range of the quantizer.  Default value = 255.
.TP
.BI \-min " min\_value"
Float. Minimum value of the range of the quantizer.  Default value = 0.
.TP
.BI \-u " u"
Float.  Apply a u-law compander to the uniform quantizer.
.TP
.BI \-A " A"
Float.  Apply a A-law compander to the uniform quantizer.
.TP
.BI \-nl " num\_levels"
Integer.  Number of quantizer intervals. Default = 255.
.TP
.BI \-q " stepsize"
Float. Stepsize of uniform quantizer.
.TP
.BI \-d " deadzone"
Float. Deadzone of quantizer.
.SH DESCRIPTION
.LP
.B squniform
designs scalar quantizers based on the uniform scalar quantizer.
.B squniform
supports simple uniform scalar quantization, uniform scalar quantization
with a dead zone about zero, and u-law and A-law companding.
.LP
A uniform scalar quantizer can be created in two ways.
The first way is to specify the scalar quantizer stepsize with
the 
.B \-q
option; this type of quantizer will be called hereafter the "simple"
uniform scalar quantizer.
Encoding using this simple quantizer (i.e., with
.BR sqencode (1))
is merely a division by the stepsize; i.e.,
.IR index =
.BR rint (
.IR value / stepsize ).
.LP
The second form of uniform quantizer supported by
.B squniform
is a "general" uniform scalar quantizer.
In this type of quantizer, the reproduction levels and boundaries
are explicitly given in the output file.
The range of the general quantizer is 
.I min\_value 
through
.I max\_value 
and the number of quantization levels is
.IR num\_levels .
.B squniform
constructs
.I num\_levels
equally-sized quantizer bins between
.I min\_value
and
.IR max\_value .
Note: the key difference between the simple and general uniform
scalar quantizers is
that the range of the simple quantizer is implied to
be infinite while the range of the general scalar quantizer is finite.
However, the first and last quantizer bins of the general quantizer are
considered to be "overload" regions.
Note: quantizing with the general uniform scalar quantizer (via, for
example,
.BR sqencode (1))
requires a nearest-neighbor search and is thus slower than using a
simple quantizer.
.LP
A dead-zone quantizer can be constructed by giving both the
.I stepsize
of the quantizer (via the
.B \-q
option) and the
.I deadzone
bin size (via the
.B \-d
option).
For a dead-zone quantizer, 
.I deadzone
is the size of the quantizer bin centered at zero; that is, all values
between
.I -deadzone
and 
.I deadzone
are quantized to zero.
Beyond this dead zone about zero, the rest of the quantizer is uniform, with
bins of size
.IR stepsize .
Note: the simple uniform scalar quantizer can be considered to be a
deadzone quantizer with
.IR deadzone = stepsize .
.LP
Companding may be applied to the general uniform scalar quantizer to produce
u-law and A-law scalar quantizers.
With the
.B \-u
or
.B \-A
options, logarithmic companders with u-law or A-law
characteristics, respectively, are applied to the general
quantizer before it is output (in effect making the quantizer nonuniform).
One of u-law or A-law, but not both, may be specified.
The value
.I u
must be nonnegative;
.I A
must be 1.0 or greater.
Options
.B \-u
and
.B \-A
may not be used in conjunction with
the
.B \-q
option.
.SH "SEE ALSO"
.BR sqlloyd (1),
.BR sqencode (1),
.BR QccPackSQ (3),
.BR QccPack (3)

A. Gersho and R. Gray, 
.IR "Vector Quantization and Signal Compression" .
Norwell, MA: Kluwer Academic Publishers, 1992, pp. 151-161.

.SH AUTHOR
Copyright (C) 1997-2009  James E. Fowler
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