ucar.jpeg.jj2000.j2k.quantization.dequantizer

Interface CBlkQuantDataSrcDec

All Superinterfaces:

InvWTData, MultiResImgData

All Known Implementing Classes:

EntropyDecoder, ROIDeScaler, StdEntropyDecoder

public interface CBlkQuantDataSrcDec
extends InvWTData

This interface defines a source of quantized wavelet coefficients and methods to transfer them in a code-block by code-block basis, fro the decoder side. In each call to 'getCodeBlock()' or 'getInternCodeBlock()' a new code-block is returned.

This class is the source of data for the dequantizer. See the 'Dequantizer' 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'.

See Also:

InvWTData, CBlkWTDataSrcDec, Dequantizer, EntropyDecoder

Method Summary

Methods

Modifier and Type	Method and Description
DataBlk	getCodeBlock(int c, int m, int n, SubbandSyn sb, DataBlk cblk) Returns the specified code-block in the current tile for the specified component, as a copy (see below).
DataBlk	getInternCodeBlock(int c, int m, int n, SubbandSyn sb, DataBlk cblk) Returns the specified code-block in the current tile for the specified component (as a reference or copy).

Methods inherited from interface ucar.jpeg.jj2000.j2k.wavelet.synthesis.InvWTData

getCbULX, getCbULY, getSynSubbandTree

Methods inherited from interface ucar.jpeg.jj2000.j2k.wavelet.synthesis.MultiResImgData

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

Method Detail

getCodeBlock

DataBlk getCodeBlock(int c,
                   int m,
                   int n,
                   SubbandSyn sb,
                   DataBlk cblk)

Returns the specified code-block in the current tile for the specified component, as a copy (see below).

The returned code-block may be progressive, which is indicated by the 'progressive' variable of the returned 'DataBlk' object. If a code-block is progressive it means that in a later request to this method for the same code-block it is possible to retrieve data which is a better approximation, since meanwhile more data to decode for the code-block could have been received. If the code-block is not progressive then later calls to this method for the same code-block will return the exact same data values.

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 'DataBlk' class.

The 'ulx' and 'uly' members of the returned 'DataBlk' 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.

m - The vertical index of the code-block to return, in the specified subband.

n - The horizontal index of the code-block to return, in the specified subband.

sb - The subband in which the code-block to return is.

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:

DataBlk

getInternCodeBlock

DataBlk getInternCodeBlock(int c,
                         int m,
                         int n,
                         SubbandSyn sb,
                         DataBlk cblk)

Returns the specified code-block in the current tile for the specified component (as a reference or copy).

The returned code-block may be progressive, which is indicated by the 'progressive' variable of the returned 'DataBlk' object. If a code-block is progressive it means that in a later request to this method for the same code-block it is possible to retrieve data which is a better approximation, since meanwhile more data to decode for the code-block could have been received. If the code-block is not progressive then later calls to this method for the same code-block will return the exact same data values.

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 'DataBlk' class.

The 'ulx' and 'uly' members of the returned 'DataBlk' 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.

m - The vertical index of the code-block to return, in the specified subband.

n - The horizontal index of the code-block to return, in the specified subband.

sb - The subband in which the code-block to return is.

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:

DataBlk