ucar.jpeg.jj2000.j2k.quantization.quantizer

Interface CBlkQuantDataSrcEnc

All Superinterfaces:

ForwWTDataProps, ImgData

All Known Implementing Classes:

Quantizer, ROIScaler, StdQuantizer

public interface CBlkQuantDataSrcEnc
extends ForwWTDataProps

This interface defines a source of quantized wavelet coefficients and methods to transfer them in a code-block by code-block basis. In each call to 'getNextCodeBlock()' or 'getNextInternCodeBlock()' a new code-block is returned. The code-blocks are returned in no specific order.

This class is the source of data for the entropy coder. See the 'EntropyCoder' class.

Code-block data is returned in sign-magnitude representation, instead of the normal two's complement one. Only integral types are used. The sign magnitude representation is more adequate for entropy coding. In sign magnitude representation, the most significant bit is used for the sign (0 if positive, 1 if negative) and the magnitude of the coefficient is stored in the next M most significant bits. The rest of the bits (least significant bits) can contain a fractional value of the quantized coefficient. The number 'M' of magnitude bits is communicated in the 'magbits' member variable of the 'CBlkWTData'.

Note that no more of one object may request data, otherwise one object would get some of the data and another one another part, in no defined manner.

See Also:

ForwWTDataProps, CBlkWTDataSrc, Quantizer, EntropyCoder

Method Summary

Modifier and Type	Method and Description
CBlkWTData	getNextCodeBlock(int c, CBlkWTData cblk) Returns the next code-block in the current tile for the specified component, as a copy (see below).
CBlkWTData	getNextInternCodeBlock(int c, CBlkWTData cblk) Returns the next code-block in the current tile for the specified component.

Methods inherited from interface ucar.jpeg.jj2000.j2k.wavelet.analysis.ForwWTDataProps

getAnSubbandTree, getCbULX, getCbULY, isReversible

Methods inherited from interface ucar.jpeg.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

Method Detail

getNextCodeBlock

CBlkWTData getNextCodeBlock(int c,
                            CBlkWTData cblk)

Returns the next code-block in the current tile for the specified component, as a copy (see below). The order in which code-blocks are returned is not specified. However each code-block is returned only once and all code-blocks will be returned if the method is called 'N' times, where 'N' is the number of code-blocks in the tile. After all the code-blocks have been returned for the current tile calls to this method will return 'null'.

When changing the current tile (through 'setTile()' or 'nextTile()') this method will always return the first code-block, as if this method was never called before for the new current tile.

The data returned by this method is always a copy of the internal data of this object, if any, and it can be modified "in place" without any problems after being returned. The 'offset' of the returned data is 0, and the 'scanw' is the same as the code-block width. See the 'CBlkWTData' class.

The 'ulx' and 'uly' members of the returned 'CBlkWTData' object contain the coordinates of the top-left corner of the block, with respect to the tile, not the subband.

Parameters:

c - The component for which to return the next code-block.

cblk - If non-null this object will be used to return the new code-block. If null a new one will be allocated and returned. If the "data" array of the object is non-null it will be reused, if possible, to return the data.

Returns:

The next code-block in the current tile for component 'c', or null if all code-blocks for the current tile have been returned.

See Also:

CBlkWTData

getNextInternCodeBlock

CBlkWTData getNextInternCodeBlock(int c,
                                  CBlkWTData cblk)

Returns the next code-block in the current tile for the specified component. The order in which code-blocks are returned is not specified. However each code-block is returned only once and all code-blocks will be returned if the method is called 'N' times, where 'N' is the number of code-blocks in the tile. After all the code-blocks have been returned for the current tile calls to this method will return 'null'.

When changing the current tile (through 'setTile()' or 'nextTile()') this method will always return the first code-block, as if this method was never called before for the new current tile.

The data returned by this method can be the data in the internal buffer of this object, if any, and thus can not be modified by the caller. The 'offset' and 'scanw' of the returned data can be arbitrary. See the 'CBlkWTData' class.

The 'ulx' and 'uly' members of the returned 'CBlkWTData' object contain the coordinates of the top-left corner of the block, with respect to the tile, not the subband.

Parameters:

c - The component for which to return the next code-block.

cblk - If non-null this object will be used to return the new code-block. If null a new one will be allocated and returned. If the "data" array of the object is non-null it will be reused, if possible, to return the data.

Returns:

The next code-block in the current tile for component 'n', or null if all code-blocks for the current tile have been returned.

See Also:

CBlkWTData