qccenthuffmanencodechannel.3

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

.TH QCCENTHUFFMANENCODECHANNEL 3 "QCCPACK" ""
.SH NAME
QccENTHuffmanEncodeChannel, QccENTHuffmanDecodeChannel \- 
Huffman encoding and decoding of channels
.SH SYNOPSIS
.B #include "libQccPack.h"
.sp
.BI "int QccENTHuffmanEncodeChannel(const QccChannel *" channel ", QccBitBuffer *" output_buffer ", QccENTHuffmanTable *" table );
.br
.BI "int QccENTHuffmanDecodeChannel(QccBitBuffer *" input_buffer ", const QccChannel *" channel ", const QccENTHuffmanTable *" table );
.SH DESCRIPTION
.BR QccENTHuffmanEncodeChannel()
performs Huffman coding of the symbol stream in
.IR channel ,
outputting the binary codewords to
.IR output_buffer .
.I channel
should not contain any null symbols
(see 
.BR QccChannel (3));
use
.BR QccChannelRemoveNullSymbols (3)
to remove null symbols if needed.
.BR QccENTHuffmanEncodeChannel() 
designs a Huffman code table, via a call to
.BR QccENTHuffmanDesign (3),
specifically for the symbols in
.I channel
by estimating symbol probabilities from the number of times each
symbol occurs in 
.IR channel .
.BR QccENTHuffmanEncode (3)
is then called to produce the binary coding of the
.I channel
symbols with the newly designed Huffman code table.
Finally,
the Huffman table used is returned as
.IR huffman_table 
.RI table -> table_type
=
.BR QCCENTHUFFMAN_ENCODETABLE ).
.LP
.BR QccENTHuffmanDecodeChannel()
performs Huffman decoding of the bits in the bitstream
.IR input_buffer ,
producing a output stream of channel symbols that are stored in
.I channel .
.I channel
must be allocated prior to calling
.BR QccENTHuffmanDecodeChannel ();
.BR QccChannelGetBlockSize (3)
is called to find out how many channel symbols are to be decoded from
.IR input_buffer .
.BR QccENTHuffmanDecodeChannel ()
calls
.BR QccENTHuffmanDecode (3)
to actually do the Huffman decoding.
.SH "NOTES"
Multiple successive calls to
.BR QccENTHuffmanEncodeChannel()
are possible; in this case, the individual bitstreams produced by each
encoding appear concatenated in the final output bitstream.
.BR QccBitBufferFlush (3)
must be called after the
.I final
call to
.BR QccENTHuffmanEncodeChannel()
(but not after any of the preceeding calls to
.BR QccENTHuffmanEncodeChannel() )
to ensure that the last few bits of the
concatenated bitstream are actually written
to the output file.
Multiple calls to
.BR QccENTHuffmanDecodeChannel()
can be used to decode the concatenated bitstream produced in this fashion,
or a single call will work too.
.SH "RETURN VALUE"
These routines return 0 on success, and 1 on failure.
.SH "SEE ALSO"
.BR QccENTHuffmanEncode (3),
.BR QccENTHuffmanDecode (3),
.BR QccENTHuffmanDesign (3),
.BR QccENTHuffmanTable (3),
.BR QccChannel (3),
.BR QccPackENT (3),
.BR QccPack (3)
.LP
D. A. Huffman, "A Method for the Construction of Minimum-Redundancy Codes,"
.IR "Proceedings of the IRE" ,
vol. 40, pp. 1098-1101, September 1952.
.SH AUTHOR
Copyright (C) 1997-2009  James E. Fowler
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