Dirac - A Video Codec

Created by the British Broadcasting Corporation.

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dirac::ArithCodec< T > Class Template Reference

Abstract binary arithmetic coding class. More...

#include <arith_codec.h>

Inheritance diagram for dirac::ArithCodec< T >:

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Collaboration diagram for dirac::ArithCodec< T >:

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List of all members.

Public Member Functions

• ArithCodec (ByteIO *p_byteio, size_t number_of_contexts)

  Constructor for encoding.
  

• virtual ~ArithCodec ()

  Destructor.
  

• int Compress (T &in_data)

  Compresses the input and returns the number of bits written.
  

• void Decompress (T &out_data, const int num_bytes)

  Decompresses the bitstream and writes into the output.
  

Protected Member Functions

• virtual void DoWorkCode (T &in_data)=0

  Does the work of actually coding the data.
  

• virtual void DoWorkDecode (T &out_data)=0

  virtual decode-only functions ////////////////////////////
  

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Detailed Description

template<class T>
class dirac::ArithCodec< T >

This is an abtract binary arithmetic encoding class, used as the base for concrete classes that encode motion vectors and subband residues.

Parameters:

T

a container (most probably, or array) type

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Constructor & Destructor Documentation

template<class T>

dirac::ArithCodec< T >::ArithCodec	(	ByteIO *	p_byteio,
		size_t	number_of_contexts
	)			[inline]

Creates an ArithCodec object to decode input based on a set of parameters.

Parameters:

	p_byteio	input/output for encoded bits
	number_of_contexts	the number of contexts used

template<class T>

virtual dirac::ArithCodec< T >::~ArithCodec

(

)

[inline, virtual]

Destructor is virtual as this class is abstract.

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Member Function Documentation

template<class T>

int dirac::ArithCodec< T >::Compress

(

T &

in_data

)

[inline]

Compress takes a type T object (a container or array) and compresses it using the abstract function DoWorkCode() which is overridden in subclasses. It returns the number of bits written.

Parameters:

in_data

the input to be compressed. Non-const, since the compression may be lossy.

template<class T>

void dirac::ArithCodec< T >::Decompress	(	T &	out_data,
		const int	num_bytes
	)			[inline]

Decompresses the bitstream, up to the number of bytes specified and writes into the output subclasses.

Parameters:

	out_data	the output into which the decompressed data is written.
	num_bytes	the number of bytes to be read from the bitstream.

template<class T>

virtual void dirac::ArithCodec< T >::DoWorkCode

(

T &

in_data

)

[protected, pure virtual]

Implemented in dirac::GenericBandCodec< dirac::ArithCodec< dirac::CoeffArray > >.

template<class T>

virtual void dirac::ArithCodec< T >::DoWorkDecode

(

T &

out_data

)

[protected, pure virtual]

Implemented in dirac::GenericBandCodec< dirac::ArithCodec< dirac::CoeffArray > >.

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The documentation for this class was generated from the following file:

• arith_codec.h

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© 2004 British Broadcasting Corporation. Dirac code licensed under the Mozilla Public License (MPL) Version 1.1.
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