qccimgimagecomponentlbt.3

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

.TH QCCIMGIMAGECOMPONENTLBT 3 "QCCPACK" ""
.SH NAME
QccIMGImageComponentLBT, QccIMGImageComponentInverseLBT
\- lapped biorthogonal transform and inverse for an image component
.SH SYNOPSIS
.B #include "libQccPack.h"
.sp
.BI "int QccIMGImageComponentLBT(const QccIMGImageComponent *" image1 ", QccIMGImageComponent *" image2 ", int " overlap_sample ", int " block_size ", double " smooth_factor );
.br
.BI "int QccIMGImageComponentInverseLBT(const QccIMGImageComponent *" image1 ", QccIMGImageComponent *" image2 ", int " overlap_sample ", int " block_size ", double " smooth_factor );
.SH DESCRIPTION
.B QccIMGImageComponentLBT()
calculates the lapped biorthogonal transform (LBT) of
.IR input1 .
The result is returned in
.IR image2 ,
which must be allocated prior to calling
.BR QccIMGImageComponentLBT() .
Both 
.I image1
and
.I image2
have the same number of rows and columns.
.LP
.B QccIMGImageComponentInverseLBT()
calculates the inverse LBT of
.IR image1 ,
returning its results in
.IR image2 .
.LP
For both
.BR QccIMGImageComponentLBT() 
and
.BR QccIMGImageComponentInverseLBT() ,
.IR overlap_sample
and
.IR smooth_factor
are parameters to the prefilter and postfilter of the LBT
(see "ALGORITHM" below), while
.IR block_size
is the size of the blocks used for the DCT.
.SH "RETURN VALUE"
Both
.B QccIMGImageComponentLBT()
and
.B QccIMGImageComponentInverseLBT()
return 0 on success, 1 on error.
.SH ALGORITHM
The lapped biorthogonal transform (LBT) implemented by these routines
was proposed by Tran
.IR "et al".
In essence, the forward transform consists of a smoothing prefilter followed
by a block-based DCT.
The inverse is then a block-based inverse DCT followed by a corresponding
postfilter.
The prefilter is intended to reduce intra-block and
inter-block correlation of the block-based DCT coefficients.
.LP
The parameters to the prefilter and postfilter operations are
.IR overlap_sample ,
which is the number of samples of overlap between DCT blocks in the
prefilter and postfiler, and
.IR smooth_factor ,
which is the smoothing constant for the prefilter and postfilter.
Although performance can varying for these parameters, sugegsted values
are
.IR overlap_sample " = " block_size "/2"
and
.IR smooth_factor " = 1.333333.
.SH "SEE ALSO"
.BR QccIMGImageComponentDCT (3),
.BR QccPackIMG (3),
.BR QccPack (3)

T. D. Tran, J. Liang, and C. Tu, "Lapped transform via time-domain
pre- and post-filtering,"
.IR "IEEE Transactions on Signal Processing" ,
vol. 51, no. 6, pp. 1557-1571, June 2003.

C. Tu and T. D. Tran, "Context-based entropy coding of
block transform coefficients for image compression,"
.IR "IEEE Transactions on Image Processing" ,
vol. 11, no. 11, pp. 1271-1283, November 2002.


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