public class StdDequantizer extends Dequantizer
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.
When reversible quantization is used, this class only converts between the sign-magnitude representation and the integer (or eventually fixed-point) output, since there is no true quantization.
The output data is fixed-point two's complement for 'int' output and floating-point for 'float' output. The type of output and the number number of fractional bits for 'int' output are defined at the constructor. Each component may have a different number of fractional bits.
The reconstruction levels used by the dequantizer are exactly what is received from the entropy decoder. It is assumed that the entropy decoder always returns codewords that are midways in the decoded intervals. In this way the dequantized values will always lie midways in the quantization intervals.
OPT_PREFIX, rb, src, utrbmressrc, tIdx| Constructor and Description |
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StdDequantizer(CBlkQuantDataSrcDec src,
int[] utrb,
DecoderSpecs decSpec)
Initializes the source of compressed data.
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| 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).
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int |
getFixedPoint(int c)
Returns the position of the fixed point in the output data for the
specified component.
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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).
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getCbULX, getCbULY, getNomRangeBits, getParameterInfo, getSynSubbandTree, nextTile, setTilegetCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getResULX, getResULY, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidthclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitgetCompImgHeight, getCompImgWidth, getCompSubsX, getCompSubsY, getImgHeight, getImgULX, getImgULY, getImgWidth, getNomTileHeight, getNomTileWidth, getNumComps, getNumTiles, getNumTiles, getResULX, getResULY, getTile, getTileCompHeight, getTileCompWidth, getTileHeight, getTileIdx, getTilePartULX, getTilePartULY, getTileWidthpublic StdDequantizer(CBlkQuantDataSrcDec src, int[] utrb, DecoderSpecs decSpec)
src - From where to obtain the quantized data.rb - The number of "range bits" (bitdepth) for each component
(must be the "range bits" of the un-transformed components). For a
definition of "range bits" see the getNomRangeBits() method.qts - The quantizer type specqsss - The dequantizer step sizes specIllegalArgumentException - Thrown if 'outdt' is neither
TYPE_FLOAT nor TYPE_INT, or if 'param' specify reversible quantization
and 'outdt' is not TYPE_INT or 'fp' has non-zero values, or if 'outdt'
is TYPE_FLOAT and 'fp' has non-zero values.Dequantizer.getNomRangeBits(int)public int getFixedPoint(int c)
Note: Fractional bits are no more supported by JJ2000.
c - The index of the component.public final DataBlk getCodeBlock(int c, int m, int n, SubbandSyn sb, DataBlk cblk)
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.
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.DataBlkpublic final DataBlk getInternCodeBlock(int c, int m, int n, SubbandSyn sb, DataBlk cblk)
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.
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.DataBlkCopyright © 2015–2022 SCIFIO. All rights reserved.