This abstract class provides the general interface for quantizers. The input of a quantizer is the output of a wavelet transform. The output of the quantizer is the set of quantized wavelet coefficients represented in sign-magnitude notation (see below).

       <p>This class provides default implementation for most of the methods
       (wherever it makes sense), under the assumption that the image, component
       dimensions, and the tiles, are not modifed by the quantizer. If it is not
       the case for a particular implementation, then the methods should be
       overriden.</p><p>Sign magnitude representation is used (instead of two's complement) for
       the output 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 M most significat bits. The rest of the bits (least
       significant bits) can contain a fractional value of the quantized
       coefficient. This fractional value is not to be coded by the entropy
       coder. However, it can be used to compute rate-distortion measures with
       greater precision.</p><p>The value of M is determined for each subband as the sum of the number
       of guard bits G and the nominal range of quantized wavelet coefficients in
       the corresponding subband (Rq), minus 1:</p><p>M = G + Rq -1</p><p>The value of G should be the same for all subbands. The value of Rq
       depends on the quantization step size, the nominal range of the component
       before the wavelet transform and the analysis gain of the subband (see
       Subband).</p><p>The blocks of data that are requested should not cross subband
       boundaries.</p><p>NOTE: At the moment only quantizers that implement the
       'CBlkQuantDataSrcEnc' interface are supported.</p>

This class implements scalar quantization of integer or floating-point valued source data. The source data is the wavelet transformed image data and the output is the quantized wavelet coefficients represented in sign-magnitude (see below).

       <p>Sign magnitude representation is used (instead of two's complement) for
       the output 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 M most significat bits. The rest of the bits (least
       significant bits) can contain a fractional value of the quantized
       coefficient. This fractional value is not to be coded by the entropy
       coder. However, it can be used to compute rate-distortion measures with
       greater precision.</p><p>The value of M is determined for each subband as the sum of the number
       of guard bits G and the nominal range of quantized wavelet coefficients in
       the corresponding subband (Rq), minus 1:</p><p>M = G + Rq -1</p><p>The value of G should be the same for all subbands. The value of Rq
       depends on the quantization step size, the nominal range of the component
       before the wavelet transform and the analysis gain of the subband (see
       Subband).</p><p>The blocks of data that are requested should not cross subband
       boundaries.</p>

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.

       <p>This class is the source of data for the entropy coder. See the
       'EntropyCoder' class.</p><p>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'.</p><p>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.</p>