001: /*
002: * $RCSfile: CBlkQuantDataSrcDec.java,v $
003: * $Revision: 1.1 $
004: * $Date: 2005/02/11 05:02:18 $
005: * $State: Exp $
006: *
007: * Class: CBlkQuantDataSrcDec
008: *
009: * Description: Interface that defines a source of
010: * quantized wavelet data to be transferred in a
011: * code-block by code-block basis (decoder side).
012: *
013: *
014: *
015: * COPYRIGHT:
016: *
017: * This software module was originally developed by Raphaël Grosbois and
018: * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
019: * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
020: * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
021: * Centre France S.A) in the course of development of the JPEG2000
022: * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
023: * software module is an implementation of a part of the JPEG 2000
024: * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
025: * Systems AB and Canon Research Centre France S.A (collectively JJ2000
026: * Partners) agree not to assert against ISO/IEC and users of the JPEG
027: * 2000 Standard (Users) any of their rights under the copyright, not
028: * including other intellectual property rights, for this software module
029: * with respect to the usage by ISO/IEC and Users of this software module
030: * or modifications thereof for use in hardware or software products
031: * claiming conformance to the JPEG 2000 Standard. Those intending to use
032: * this software module in hardware or software products are advised that
033: * their use may infringe existing patents. The original developers of
034: * this software module, JJ2000 Partners and ISO/IEC assume no liability
035: * for use of this software module or modifications thereof. No license
036: * or right to this software module is granted for non JPEG 2000 Standard
037: * conforming products. JJ2000 Partners have full right to use this
038: * software module for his/her own purpose, assign or donate this
039: * software module to any third party and to inhibit third parties from
040: * using this software module for non JPEG 2000 Standard conforming
041: * products. This copyright notice must be included in all copies or
042: * derivative works of this software module.
043: *
044: * Copyright (c) 1999/2000 JJ2000 Partners.
045: * */
046: package jj2000.j2k.quantization.dequantizer;
047:
048: import jj2000.j2k.wavelet.synthesis.*;
049: import jj2000.j2k.entropy.decoder.*;
050: import jj2000.j2k.image.*;
051:
052: /**
053: * This interface defines a source of quantized wavelet coefficients and
054: * methods to transfer them in a code-block by code-block basis, fro the
055: * decoder side. In each call to 'getCodeBlock()' or 'getInternCodeBlock()' a
056: * new code-block is returned.
057: *
058: * <P>This class is the source of data for the dequantizer. See the
059: * 'Dequantizer' class.
060: *
061: * <P>Code-block data is returned in sign-magnitude representation, instead of
062: * the normal two's complement one. Only integral types are used. The sign
063: * magnitude representation is more adequate for entropy coding. In sign
064: * magnitude representation, the most significant bit is used for the sign (0
065: * if positive, 1 if negative) and the magnitude of the coefficient is stored
066: * in the next M most significant bits. The rest of the bits (least
067: * significant bits) can contain a fractional value of the quantized
068: * coefficient. The number 'M' of magnitude bits is communicated in the
069: * 'magbits' member variable of the 'CBlkWTData'.
070: *
071: * @see InvWTData
072: * @see CBlkWTDataSrcDec
073: * @see Dequantizer
074: * @see EntropyDecoder
075: * */
076: public interface CBlkQuantDataSrcDec extends InvWTData {
077:
078: /**
079: * Returns the specified code-block in the current tile for the specified
080: * component, as a copy (see below).
081: *
082: * <p>The returned code-block may be progressive, which is indicated by
083: * the 'progressive' variable of the returned 'DataBlk' object. If a
084: * code-block is progressive it means that in a later request to this
085: * method for the same code-block it is possible to retrieve data which is
086: * a better approximation, since meanwhile more data to decode for the
087: * code-block could have been received. If the code-block is not
088: * progressive then later calls to this method for the same code-block
089: * will return the exact same data values.</p>
090: *
091: * <p>The data returned by this method is always a copy of the internal
092: * data of this object, if any, and it can be modified "in place" without
093: * any problems after being returned. The 'offset' of the returned data is
094: * 0, and the 'scanw' is the same as the code-block width. See the
095: * 'DataBlk' class.</p>
096: *
097: * <p>The 'ulx' and 'uly' members of the returned 'DataBlk' object contain
098: * the coordinates of the top-left corner of the block, with respect to
099: * the tile, not the subband.</p>
100: *
101: * @param c The component for which to return the next code-block.
102: *
103: * @param m The vertical index of the code-block to return, in the
104: * specified subband.
105: *
106: * @param n The horizontal index of the code-block to return, in the
107: * specified subband.
108: *
109: * @param sb The subband in which the code-block to return is.
110: *
111: * @param cblk If non-null this object will be used to return the new
112: * code-block. If null a new one will be allocated and returned. If the
113: * "data" array of the object is non-null it will be reused, if possible,
114: * to return the data.
115: *
116: * @return The next code-block in the current tile for component 'n', or
117: * null if all code-blocks for the current tile have been returned.
118: *
119: * @see DataBlk
120: * */
121: public DataBlk getCodeBlock(int c, int m, int n, SubbandSyn sb,
122: DataBlk cblk);
123:
124: /**
125: * Returns the specified code-block in the current tile for the specified
126: * component (as a reference or copy).
127: *
128: * <p>The returned code-block may be progressive, which is indicated by
129: * the 'progressive' variable of the returned 'DataBlk' object. If a
130: * code-block is progressive it means that in a later request to this
131: * method for the same code-block it is possible to retrieve data which is
132: * a better approximation, since meanwhile more data to decode for the
133: * code-block could have been received. If the code-block is not
134: * progressive then later calls to this method for the same code-block
135: * will return the exact same data values.</p>
136: *
137: * <p>The data returned by this method can be the data in the internal
138: * buffer of this object, if any, and thus can not be modified by the
139: * caller. The 'offset' and 'scanw' of the returned data can be
140: * arbitrary. See the 'DataBlk' class.</p>
141: *
142: * <p>The 'ulx' and 'uly' members of the returned 'DataBlk' object contain
143: * the coordinates of the top-left corner of the block, with respect to
144: * the tile, not the subband.</p>
145: *
146: * @param c The component for which to return the next code-block.
147: *
148: * @param m The vertical index of the code-block to return, in the
149: * specified subband.
150: *
151: * @param n The horizontal index of the code-block to return, in the
152: * specified subband.
153: *
154: * @param sb The subband in which the code-block to return is.
155: *
156: * @param cblk If non-null this object will be used to return the new
157: * code-block. If null a new one will be allocated and returned. If the
158: * "data" array of the object is non-null it will be reused, if possible,
159: * to return the data.
160: *
161: * @return The next code-block in the current tile for component 'n', or
162: * null if all code-blocks for the current tile have been returned.
163: *
164: * @see DataBlk
165: * */
166: public DataBlk getInternCodeBlock(int c, int m, int n,
167: SubbandSyn sb, DataBlk cblk);
168: }
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