Dirac - A Video Codec

Created by the British Broadcasting Corporation.


Public Member Functions | Private Member Functions | Private Attributes
dirac::IntraDCBandCodec Class Reference

A class specially for coding the DC subband of Intra frames. More...

#include <band_codec.h>

Inheritance diagram for dirac::IntraDCBandCodec:
Inheritance graph
[legend]
Collaboration diagram for dirac::IntraDCBandCodec:
Collaboration graph
[legend]

List of all members.

Public Member Functions

 IntraDCBandCodec (SubbandByteIO *subband_byteio, size_t number_of_contexts, const SubbandList &band_list)
 Constructor.
- Public Member Functions inherited from dirac::GenericIntraDCBandCodec< ArithCodec< CoeffArray > >
 GenericIntraDCBandCodec (SubbandByteIO *subband_byteio, size_t number_of_contexts, const SubbandList &band_list)
 Constructor.
- Public Member Functions inherited from dirac::GenericBandCodec< ArithCodec< CoeffArray > >
 GenericBandCodec (SubbandByteIO *subband_byteio, size_t number_of_contexts, const SubbandList &band_list, int band_num, const bool is_intra)
 Constructor.
- Public Member Functions inherited from dirac::ArithCodec< CoeffArray >
 ArithCodec (ByteIO *p_byteio, size_t number_of_contexts)
 Constructor for encoding.
virtual ~ArithCodec ()
 Destructor.
int Compress (CoeffArray &in_data)
 Compresses the input and returns the number of bits written.
void Decompress (CoeffArray &out_data, const int num_bytes)
 Decompresses the bitstream and writes into the output.
- Public Member Functions inherited from dirac::ArithCodecBase
 ArithCodecBase (ByteIO *p_byteio, size_t number_of_contexts)
 Constructor.
virtual ~ArithCodecBase ()
 Destructor.

Private Member Functions

void DoWorkCode (CoeffArray &in_data)
 Initialize extra data required for error-feedback DC quantization.
void DoWorkDecode (CoeffArray &out_data)
 Ditto.
void CodeCoeff (CoeffArray &in_data, const int xpos, const int ypos)
 Encode a single coefficient using error-feedback DC quantization.
void DecodeCoeff (CoeffArray &out_data, const int xpos, const int ypos)
 Decode a single coefficient using error-feedback DC quantization.
 IntraDCBandCodec (const IntraDCBandCodec &cpy)
 Private, bodyless copy constructor: class should not be copied.
IntraDCBandCodecoperator= (const IntraDCBandCodec &rhs)
 Private, bodyless copy operator=: class should not be assigned.

Private Attributes

CoeffArray m_dc_pred_res

Additional Inherited Members

- Protected Member Functions inherited from dirac::GenericIntraDCBandCodec< ArithCodec< CoeffArray > >
void ClearBlock (const CodeBlock &code_block, CoeffArray &coeff_data)
 When coding a skipped block, propegate the predicted values for future non skipped blocks.
CoeffType GetPrediction (const CoeffArray &data, const int xpos, const int ypos) const
 Prediction of a DC value from its previously coded neighbours.
void DecodeCoeffBlock (const CodeBlock &code_block, CoeffArray &out_data)
 Decode codeblock of coefficients and perform DC prediction.
- Protected Member Functions inherited from dirac::GenericBandCodec< ArithCodec< CoeffArray > >
void CodeVal (CoeffArray &in_data, const int xpos, const int ypos, const CoeffType val)
 Code an individual quantised value and perform inverse-quantisation.
void DecodeVal (CoeffArray &out_data, const int xpos, const int ypos)
 Decode an individual quantised value and perform inverse-quantisation.
void CodeQuantIndexOffset (const int offset)
 Encode the offset for a code block quantiser.
int DecodeQuantIndexOffset ()
 Decode the offset for a code block quantiser.
void SetToVal (const CodeBlock &code_block, CoeffArray &coeff_data, const CoeffType val)
 Set a code block area to a given value.
virtual void CodeCoeffBlock (const CodeBlock &code_block, CoeffArray &in_data)
int ChooseFollowContext (const int bin_number) const
 A function for choosing the context for "follow bits".
int ChooseInfoContext () const
 A function for choosing the context for "information bits".
int ChooseSignContext (const CoeffArray &data, const int xpos, const int ypos) const
 A function for choosing the context for sign bits.

Detailed Description

A class specially for coding the DC subband of Intra frames, using intra-band prediction of coefficients. It uses the abstract ArithCodec class


Constructor & Destructor Documentation

dirac::IntraDCBandCodec::IntraDCBandCodec ( SubbandByteIO subband_byteio,
size_t  number_of_contexts,
const SubbandList band_list 
)
inline

Creates a IntraDCBandCodec object to encode subband data, based on parameters

Parameters:
subband_byteioinput/output for the encoded bits
number_of_contextsthe number of contexts used in the encoding process
band_listthe set of all the subbands
dirac::IntraDCBandCodec::IntraDCBandCodec ( const IntraDCBandCodec cpy)
private

Member Function Documentation

void dirac::IntraDCBandCodec::CodeCoeff ( CoeffArray in_data,
const int  xpos,
const int  ypos 
)
privatevirtual
void dirac::IntraDCBandCodec::DecodeCoeff ( CoeffArray out_data,
const int  xpos,
const int  ypos 
)
privatevirtual
void dirac::IntraDCBandCodec::DoWorkCode ( CoeffArray in_data)
privatevirtual
void dirac::IntraDCBandCodec::DoWorkDecode ( CoeffArray out_data)
privatevirtual
IntraDCBandCodec& dirac::IntraDCBandCodec::operator= ( const IntraDCBandCodec rhs)
private

Member Data Documentation

CoeffArray dirac::IntraDCBandCodec::m_dc_pred_res
private

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

© 2004 British Broadcasting Corporation. Dirac code licensed under the Mozilla Public License (MPL) Version 1.1.
HTML documentation generated by Dimitri van Heesch's excellent Doxygen tool.