jj2000.j2k.entropy.encoder

Class EntropyCoder

java.lang.Object

jj2000.j2k.image.ImgDataAdapter

jj2000.j2k.entropy.encoder.EntropyCoder

All Implemented Interfaces:

CodedCBlkDataSrcEnc, StdEntropyCoderOptions, ImgData, ForwWTDataProps

Direct Known Subclasses:

StdEntropyCoder

public abstract class EntropyCoder
extends ImgDataAdapter
implements CodedCBlkDataSrcEnc, StdEntropyCoderOptions

This abstract class provides the general interface for block-based entropy encoders. The input to the entropy coder is the quantized wavelet coefficients, or codewords, represented in sign magnitude. The output is a compressed code-block with rate-distortion information.

The source of data for objects of this class are 'CBlkQuantDataSrcEnc' objects.

For more details on the sign magnitude representation used see the Quantizer class.

This class provides default implemenations for most of the methods (wherever it makes sense), under the assumption that the image and component dimensions, and the tiles, are not modifed by the entropy coder. If that is not the case for a particular implementation then the methods should be overriden.

See Also:

Quantizer, CBlkQuantDataSrcEnc

Field Summary

Fields

Modifier and Type	Field and Description
static char	OPT_PREFIX The prefix for entropy coder options: 'C'
private static String[][]	pinfo The list of parameters that is accepted for entropy coding.
protected CBlkQuantDataSrcEnc	src The source of quantized wavelet coefficients

Fields inherited from class jj2000.j2k.image.ImgDataAdapter

imgdatasrc, tIdx

Fields inherited from interface jj2000.j2k.entropy.StdEntropyCoderOptions

FIRST_BYPASS_PASS_IDX, MAX_CB_AREA, MAX_CB_DIM, MIN_CB_DIM, NUM_EMPTY_PASSES_IN_MS_BP, NUM_NON_BYPASS_MS_BP, NUM_PASSES, OPT_BYPASS, OPT_PRED_TERM, OPT_RESET_MQ, OPT_SEG_SYMBOLS, OPT_TERM_PASS, OPT_VERT_STR_CAUSAL, STRIPE_HEIGHT

Constructor Summary

Constructors

Constructor and Description
EntropyCoder(CBlkQuantDataSrcEnc src) Initializes the source of quantized wavelet coefficients.

Method Summary

Modifier and Type	Method and Description
static EntropyCoder	createInstance(CBlkQuantDataSrcEnc src, J2KImageWriteParamJava wp, CBlkSizeSpec cblks, PrecinctSizeSpec pss, StringSpec bms, StringSpec mqrs, StringSpec rts, StringSpec css, StringSpec sss, StringSpec lcs, StringSpec tts) Creates a EntropyCoder object for the appropriate entropy coding parameters in the parameter list 'pl', and having 'src' as the source of quantized data.
SubbandAn	getAnSubbandTree(int t, int c) Returns a reference to the root of subband tree structure representing the subband decomposition for the specified tile-component.
abstract int	getCBlkHeight(int t, int c) Returns the code-block height for the specified tile and component.
abstract int	getCBlkWidth(int t, int c) Returns the code-block width for the specified tile and component.
int	getCbULX() Returns the horizontal offset of the code-block partition.
int	getCbULY() Returns the vertical offset of the code-block partition.
static String[][]	getParameterInfo() Returns the parameters that are used in this class and implementing classes.
boolean	isReversible(int t, int c) Returns the reversibility of the tile-component data that is provided by the object.

Methods inherited from class jj2000.j2k.image.ImgDataAdapter

getCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getCompULX, getCompULY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomRangeBits, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidth, nextTile, setTile

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface jj2000.j2k.entropy.encoder.CodedCBlkDataSrcEnc

getNextCodeBlock, getPPX, getPPY, precinctPartitionUsed

Methods inherited from interface jj2000.j2k.image.ImgData

getCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getCompULX, getCompULY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomRangeBits, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidth, nextTile, setTile

Field Detail

OPT_PREFIX

public static final char OPT_PREFIX

The prefix for entropy coder options: 'C'

See Also:

Constant Field Values

pinfo

private static final String[][] pinfo

The list of parameters that is accepted for entropy coding. Options for entropy coding start with 'C'.

src

protected CBlkQuantDataSrcEnc src

The source of quantized wavelet coefficients

Constructor Detail

EntropyCoder

public EntropyCoder(CBlkQuantDataSrcEnc src)

Initializes the source of quantized wavelet coefficients.

Parameters:

src - The source of quantized wavelet coefficients.

Method Detail

getCBlkWidth

public abstract int getCBlkWidth(int t,
                                 int c)

Returns the code-block width for the specified tile and component.

Parameters:

t - The tile index

c - the component index

Returns:

The code-block width for the specified tile and component

getCBlkHeight

public abstract int getCBlkHeight(int t,
                                  int c)

Returns the code-block height for the specified tile and component.

Parameters:

t - The tile index

c - the component index

Returns:

The code-block height for the specified tile and component

isReversible

public boolean isReversible(int t,
                            int c)

Returns the reversibility of the tile-component data that is provided by the object. Data is reversible when it is suitable for lossless and lossy-to-lossless compression.

Since entropy coders themselves are always reversible, it returns the reversibility of the data that comes from the 'CBlkQuantDataSrcEnc' source object (i.e. ROIScaler).

Specified by:

isReversible in interface ForwWTDataProps

Parameters:

t - Tile index

c - Component index

Returns:

true is the data is reversible, false if not.

See Also:

ROIScaler

getAnSubbandTree

public SubbandAn getAnSubbandTree(int t,
                                  int c)

Returns a reference to the root of subband tree structure representing the subband decomposition for the specified tile-component.

Specified by:

getAnSubbandTree in interface ForwWTDataProps

Parameters:

t - The index of the tile.

c - The index of the component.

Returns:

The root of the subband tree structure, see Subband.

See Also:

SubbandAn, Subband

getCbULX

public int getCbULX()

Returns the horizontal offset of the code-block partition. Allowable values are 0 and 1, nothing else.

Specified by:

getCbULX in interface ForwWTDataProps

getCbULY

public int getCbULY()

Returns the vertical offset of the code-block partition. Allowable values are 0 and 1, nothing else.

Specified by:

getCbULY in interface ForwWTDataProps

getParameterInfo

public static String[][] getParameterInfo()

Returns the parameters that are used in this class and implementing classes. It returns a 2D String array. Each of the 1D arrays is for a different option, and they have 3 elements. The first element is the option name, the second one is the synopsis, the third one is a long description of what the parameter is and the fourth is its default value. The synopsis or description may be 'null', in which case it is assumed that there is no synopsis or description of the option, respectively. Null may be returned if no options are supported.

Returns:

the options name, their synopsis and their explanation, or null if no options are supported.

createInstance

public static EntropyCoder createInstance(CBlkQuantDataSrcEnc src,
                                          J2KImageWriteParamJava wp,
                                          CBlkSizeSpec cblks,
                                          PrecinctSizeSpec pss,
                                          StringSpec bms,
                                          StringSpec mqrs,
                                          StringSpec rts,
                                          StringSpec css,
                                          StringSpec sss,
                                          StringSpec lcs,
                                          StringSpec tts)

Creates a EntropyCoder object for the appropriate entropy coding parameters in the parameter list 'pl', and having 'src' as the source of quantized data.

Parameters:

src - The source of data to be entropy coded

wp - The parameter list (or options).

cblks - Code-block size specifications

pss - Precinct partition specifications

bms - By-pass mode specifications

mqrs - MQ-reset specifications

rts - Regular termination specifications

css - Causal stripes specifications

sss - Error resolution segment symbol use specifications

lcs - Length computation specifications

tts - Termination type specifications

Throws:

IllegalArgumentException - If an error occurs while parsing the options in 'pl'