qccchannelentropy.3

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

.TH QCCCHANNELENTROPY 3 "QCCPACK" ""
.SH NAME
QccChannelEntropy
\- calculate entropy of symbols of channel
.SH SYNOPSIS
.B #include "libQccPack.h"
.sp
.BI "double QccChannelEntropy(const QccChannel *" channel ", int " order );
.SH DESCRIPTION
.B QccChannelEntropy()
calculates the first- or second-order entropy of the
current block of symbols,
.IR channel -> channel_symbols .
The order, 1 for first-order or 2 for second-order, is given by
.IR order .
.LP
If order 1 is specified, the first-order entropy (sometimes called
the zero-order entropy) is calculated as 
.IR H(X(t)) ,
where 
.I X(t)
is the random process represented by the channel symbols,
.IR channel -> channel_symbols .
If order 2 is specified, the second-order conditional entropy,
.IR H(X(t) " | " X(t-1)) ,
is calculated;
this is the average entropy of the current symbol conditioned on the
preceding symbol and is an estimate of the entropy rate
of a first-order Markov source.
Of course,
.I X(t)
is assumed to be stationary and ergodic.
.LP
For the first-order entropy calculation,
.B QccChannelEntropy()
calulates the probability of occurrence of each symbol in the
current block of symbols.
For the second-order entropy calculation,
a probability matrix is calculated to give the probability of
each symbol conditioned on the previous symbol.
.B QccENTConditionalEntropy (3)
is used to perform the entropy calculation in each case.
.SH "RETURN VALUE"
On successful completion, the value of the entropy (a nonnegative number)
is returned.  On error, -1.0 is returned.
.SH "SEE ALSO"
.BR QccENTConditionalEntropy (3),
.BR QccPackENT (3),
.BR QccChannel (3),
.BR QccPack (3)

T. M. Cover and J. T. Thomas, 
.IR "Elements of Information Theory" .
New York: John Wiley & Sons, Inc., 1991.

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

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