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/*
* $RCSfile: Dequantizer.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:18 $
* $State: Exp $
*
* Class: Dequantizer
*
* Description: The abstract class for all dequantizers.
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
*/
package jj2000.j2k.quantization.dequantizer;
import jj2000.j2k.decoder.DecoderSpecs;
import jj2000.j2k.image.CompTransfSpec;
import jj2000.j2k.image.invcomptransf.InvCompTransf;
import jj2000.j2k.wavelet.Subband;
import jj2000.j2k.wavelet.synthesis.CBlkWTDataSrcDec;
import jj2000.j2k.wavelet.synthesis.MultiResImgDataAdapter;
import jj2000.j2k.wavelet.synthesis.SubbandSyn;
import jj2000.j2k.wavelet.synthesis.SynWTFilterSpec;
/**
* This is the abstract class from which all dequantizers must inherit. This
* class has the concept of a current tile and all operations are performed on
* the current tile.
*
* 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 dequantizer. If
* that is not the case for a particular implementation then the methods
* should be overriden.
*
* Sign magnitude representation is used (instead of two's complement) for
* the input data. The most significant bit is used for the sign (0 if
* positive, 1 if negative). Then the magnitude of the quantized coefficient
* is stored in the next most significat bits. The most significant magnitude
* bit corresponds to the most significant bit-plane and so on.
*
* The output data is either in floating-point, or in fixed-point two's
* complement. In case of floating-point data the the value returned by
* getFixedPoint() must be 0. If the case of fixed-point data the number of
* fractional bits must be defined at the constructor of the implementing
* class and all operations must be performed accordingly. Each component may
* have a different number of fractional bits.
* */
public abstract class Dequantizer extends MultiResImgDataAdapter
implements CBlkWTDataSrcDec {
/** The prefix for dequantizer options: 'Q' */
public final static char OPT_PREFIX = 'Q';
/** The list of parameters that is accepted by the bit stream
* readers. They start with 'Q' */
private static final String [][] pinfo = null;
/** The entropy decoder from where to get the quantized data (the
* source). */
protected CBlkQuantDataSrcDec src;
/** The "range bits" for each transformed component */
protected int rb[] = null;
/** The "range bits" for each un-transformed component */
protected int utrb[] = null;
/** The inverse component transformation specifications */
private CompTransfSpec cts;
/** Reference to the wavelet filter specifications */
private SynWTFilterSpec wfs;
/**
* Initializes the source of compressed data.
*
* @param src From where to obtain the quantized data.
*
* @param rb The number of "range bits" for each component (must be the
* "range bits" of the un-transformed components. For a definition of
* "range bits" see the getNomRangeBits() method.
*
* @see #getNomRangeBits
* */
public Dequantizer(CBlkQuantDataSrcDec src,int utrb[],
DecoderSpecs decSpec) {
super(src);
if (utrb.length != src.getNumComps()) {
throw new IllegalArgumentException();
}
this.src = src;
this.utrb = utrb;
this.cts = decSpec.cts;
this.wfs = decSpec.wfs;
}
/**
* Returns the number of bits, referred to as the "range bits",
* corresponding to the nominal range of the data in the specified
* component.
*
* The returned value corresponds to the nominal dynamic range of the
* reconstructed image data, not of the wavelet coefficients
* themselves. This is because different subbands have different gains and
* thus different nominal ranges. To have an idea of the nominal range in
* each subband the subband analysis gain value from the subband tree
* structure, returned by the getSynSubbandTree() method, can be used. See
* the Subband class for more details.
*
* If this number is b then for unsigned data the nominal range
* is between 0 and 2^b-1, and for signed data it is between -2^(b-1) and
* 2^(b-1)-1.
*
* @param c The index of the component
*
* @return The number of bits corresponding to the nominal range of the
* data.
*
* @see Subband
* */
public int getNomRangeBits(int c) {
return rb[c];
}
/**
* Returns the subband tree, for the specified tile-component. This method
* returns the root element of the subband tree structure, see Subband and
* SubbandSyn. The tree comprises all the available resolution levels.
*
* The number of magnitude bits ('magBits' member variable) for each
* subband may have not been not initialized (it depends on the actual
* dequantizer and its implementation). However, they are not necessary
* for the subsequent steps in the decoder chain.
*
* @param t The index of the tile, from 0 to T-1.
*
* @param c The index of the component, from 0 to C-1.
*
* @return The root of the tree structure.
* */
public SubbandSyn getSynSubbandTree(int t,int c) {
return src.getSynSubbandTree(t,c);
}
/**
* Returns the horizontal code-block partition origin. Allowable values
* are 0 and 1, nothing else.
* */
public int getCbULX() {
return src.getCbULX();
}
/**
* Returns the vertical code-block partition origin. Allowable values are
* 0 and 1, nothing else.
* */
public int getCbULY() {
return src.getCbULY();
}
/**
* 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 and the third one is a long description of what
* the parameter is. 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.
*
* @return the options name, their synopsis and their explanation,
* or null if no options are supported.
* */
public static String[][] getParameterInfo() {
return pinfo;
}
/**
* Changes the current tile, given the new indexes. An
* IllegalArgumentException is thrown if the indexes do not
* correspond to a valid tile.
*
*
This default implementation changes the tile in the source
* and re-initializes properly component transformation variables..
*
* @param x The horizontal index of the tile.
*
* @param y The vertical index of the new tile.
* */
public void setTile(int x, int y) {
src.setTile(x,y);
tIdx = getTileIdx(); // index of the current tile
// initializations
int cttype = 0;
if( ((Integer)cts.getTileDef(tIdx)).intValue()==InvCompTransf.NONE )
cttype = InvCompTransf.NONE;
else {
int nc = src.getNumComps() > 3 ? 3 : src.getNumComps();
int rev = 0;
for(int c=0; cThis default implementation just advances to the next tile in the
* source and re-initializes properly component transformation variables.
* */
public void nextTile() {
src.nextTile();
tIdx = getTileIdx(); // index of the current tile
// initializations
int cttype = ((Integer)cts.getTileDef(tIdx)).intValue();
switch(cttype){
case InvCompTransf.NONE:
rb = utrb;
break;
case InvCompTransf.INV_RCT:
rb = InvCompTransf.
calcMixedBitDepths(utrb,InvCompTransf.INV_RCT,null);
break;
case InvCompTransf.INV_ICT:
rb = InvCompTransf.
calcMixedBitDepths(utrb,InvCompTransf.INV_ICT,null);
break;
default:
throw new IllegalArgumentException("Non JPEG 2000 part I "+
"component"+
" transformation for tile: "+
tIdx);
}
}
}