sqlloyd.1

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

.TH SQLLOYD 1 "QCCPACK" ""
.SH NAME
sqlloyd \- design Lloyd optimal mean-square scalar quantizer for Gaussian and 
Laplacian densities
.SH SYNOPSIS
.B sqlloyd
.RB "[\|" \-max
.IR  max\_value "\|]"
.RB "[\|" \-min
.IR min\_value "\|]"
.RB "[\|" \-nl
.IR num\_levels "\|]"
.RB "[\|" \-v
.IR variance "\|]"
.RB "[\|" \-l "\|]"
.RB "[\|" \-t
.IR stop\_threshold "\|]"
.RB "[\|" \-i
.IR integration\_intervals "\|]"
.I quantizer\_file
.SH OPTIONS
.TP
.BI \-max " max\_value"
Float. Maximum value of the range of the quantizer.  Default value = 10.
.TP
.BI \-min " min\_value"
Float. Minimum value of the range of the quantizer.  Default value = -10.
.TP
.BI \-nl " num\_levels"
Integer.  Number of quantizer intervals. Default = 255.
.TP
.BI \-v " variance"
Float.  Variance of the Gaussian or Laplacian density.  Default = 1.0.
.TP
.B \-l
Use Laplacian density.  The default is to use a Gaussian density.
.TP
.BI \-t " stop\_threshold"
Float.  Stop the design process when the average distortion (MSE) 
changes by less than 
.I stop\_threshold
from one iteration to the next; that is, stop if
(D(i-1) - D(i))/D(i) <
.IR threshold ,
where D(i) is the average distortion (MSE) for the ith iteration.
.TP
.BI \-i " integration\_intervals"
Float.  Specifies the number of intervals to use in the numeric integration
used tp calculate partition probabilities and centroids.
.SH DESCRIPTION
.LP
.B sqlloyd
designs a scalar quantizer to minimize the mean-square error (MSE)
for the given probability density and number of quantizer levels.
The designed quantizer is output to
.IR quantizer\_file .
The range of the quantizer is 
.I min\_value 
through
.IR max\_value .
The number of quantization levels is
.IR num\_levels .
.LP
If the
.B \-l
option is specified, a Laplacian density is used.  Otherwise, a Gaussian
density is used.  In either case, 
.I variance
is the variance of the density to be used.
The mean of the density is assumed to be
.RI ( max\_value + min\_value ")/2."
.LP
The Lloyd algorithm involves finding the first moment of each partition
and the probability of each partition.  Numerical integration using
Simpon's Rule is used in each of these calculations.  The value
of
.I integration\_intervals
gives the number of intervals to use in Simpson's Rule.
The more intervals used, the more accurate will be the the integration, but
using more levels increases the computation time.  100 to 1000 intervals
is probably sufficient for most applications.
.LP
The design process stops when the average distortion of the quantizer changes
by less than
.I stop\_threshold
between iterations.  Small values yield better quantizers yet longer
computation time.  Values in the range 0.001 to 0.000001 are probably 
sufficient for most applications.
.SH "SEE ALSO"
.BR sqlloyd (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. 187-194.

A. K. Jain,
.IR "Fundamentals of Digital Image Processing" .
Englewood Cliffs, NJ: Prentice Hall, 1989, pp. 101-112.

.SH AUTHOR
Copyright (C) 1997-2009  James E. Fowler
.\"  The programs herein are free software; you can redistribute them and/or
.\"  modify them under the terms of the GNU General Public License
.\"  as published by the Free Software Foundation; either version 2
.\"  of the License, or (at your option) any later version.
.\"  
.\"  These programs are distributed in the hope that they will be useful,
.\"  but WITHOUT ANY WARRANTY; without even the implied warranty of
.\"  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\"  GNU General Public License for more details.
.\"  
.\"  You should have received a copy of the GNU General Public License
.\"  along with these programs; if not, write to the Free Software
.\"  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.