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/************************************************************************
*
* quant.c, part of tmn (TMN encoder)
*
* Copyright (C) 1997 University of BC, Canada
*
* Contacts:
* Michael Gallant <mikeg@ee.ubc.ca>
* Guy Cote <guyc@ee.ubc.ca>
* Berna Erol <bernae@ee.ubc.ca>
*
* UBC Image Processing Laboratory http://www.ee.ubc.ca/image
* 2356 Main Mall tel.: +1 604 822 4051
* Vancouver BC Canada V6T1Z4 fax.: +1 604 822 5949
*
* Copyright (C) 1995, 1996 Telenor R&D, Norway
*
* Contacts:
* Robert Danielsen <Robert.Danielsen@nta.no>
*
* Telenor Research and Development http://www.nta.no/brukere/DVC/
* P.O.Box 83 tel.: +47 63 84 84 00
* N-2007 Kjeller, Norway fax.: +47 63 81 00 76
*
************************************************************************/
/* Disclaimer of Warranty
*
* These software programs are available to the user without any license fee
* or royalty on an "as is" basis. The University of British Columbia
* disclaims any and all warranties, whether express, implied, or
* statuary, including any implied warranties or merchantability or of
* fitness for a particular purpose. In no event shall the
* copyright-holder be liable for any incidental, punitive, or
* consequential damages of any kind whatsoever arising from the use of
* these programs.
*
* This disclaimer of warranty extends to the user of these programs and
* user's customers, employees, agents, transferees, successors, and
* assigns.
*
* The University of British Columbia does not represent or warrant that the
* programs furnished hereunder are free of infringement of any
* third-party patents.
*
* Commercial implementations of H.263, including shareware, are subject to
* royalty fees to patent holders. Many of these patents are general
* enough such that they are unavoidable regardless of implementation
* design.
*
*/
#include"sim.h"
static int MQ_chroma_QP_table[32] = {0,1,2,3,4,5,6,6,7,8,9,9,10,10,11,11,12,12,12,13,13,13,14,14,14,14,14,15,15,15,15,15};
/**********************************************************************
*
* Name: Quant_blk
* Description: quantizer
*
* Input: pointers to coeff and qcoeff
*
* Returns:
* Side effects:
*
* Date: 940111 Author: <klillevo@mailbox.jf.intel.com>
*
***********************************************************************/
void Quant_blk (int *coeff, int *qcoeff, int QP, int Mode, int block)
{
int i;
int level;
/*Modify the chroma quantizer if modified quantization mode is in use*/
if (modified_quantization && (block == 4 || block == 5))
{
QP=MQ_chroma_QP_table[QP];
}
if (QP)
{
if (Mode == MODE_INTRA || Mode == MODE_INTRA_Q)
{ /* Intra */
/* advanced intra coding quantization */
if (advanced_intra_coding)
{
for (i = 0; i < 64; i++)
{
qcoeff[block*64 + i] = (coeff[block*64 + i] + sign(coeff[block*64 + i]) * QP/2) / (2 * QP);
}
} else
{
qcoeff[block*64] = mmax (1, mmin (254, (coeff[block*64]+4) / 8));
for (i = 1; i < 64; i++)
{
level = (abs (coeff[block*64 + i])) / (2 * QP);
/* if QP is larger than 8, don't use extended quantization */
if (!modified_quantization || QP >= 8)
{
/* clipping to [-127,+127] */
qcoeff[block*64 + i] = mmin (127, mmax (-127, sign (coeff[block*64 + i]) * level));
} else
{
/* no clipping, quantized coefficients */
qcoeff[block*64 + i] = sign (coeff[block*64 + i]) * level;
}
}
}
}
else
{ /* non Intra */
for (i = 0; i < 64; i++)
{
level = (abs (coeff[block*64 + i]) - QP / 2) / (2 * QP);
/* if QP is larger than 8, don't use extended quantization */
if (!modified_quantization || QP >= 8)
{
/* clipping to [-127,+127] */
qcoeff[block*64 + i] = mmin (127, mmax (-127, sign (coeff[block*64 + i]) * level));
} else
{
/* no clipping, quantized coefficients */
qcoeff[block*64 + i] = sign (coeff[block*64 + i]) * level;
}
}
}
}
else
{
/* No quantizing. Used only for testing. Bitstream will not be
* decodable whether clipping is performed or not */
for (i = 0; i < 64; i++)
{
qcoeff[block*64 + i] = coeff[block*64 + i];
}
}
return;
}
/**********************************************************************
*
* Name: Dequant
* Description: dequantizer
*
* Input: pointers to coeff and qcoeff
*
* Returns:
* Side effects:
*
* Date: 940111 Author: Karl.Lillevold@nta.no
*
***********************************************************************/
void Dequant (int *qcoeff,int *rcoeff, int QP, int Mode, int block)
{
int i;
/* Modify the chorama quantizer if modified quantization mode is in use */
if (modified_quantization && (block == 4 || block == 5))
{
QP=MQ_chroma_QP_table[QP];
}
if (QP)
{
for (i = 0; i < 64; i++)
{
if (qcoeff[block * 64 + i])
{
if ((advanced_intra_coding) && (Mode == MODE_INTRA || Mode == MODE_INTRA_Q))
{
/* Advanced intra coding dequantization */
rcoeff[block * 64 + i] = (QP * (2 * qcoeff[block * 64 + i]));
} else
{
if ((QP % 2) == 1)
rcoeff[block * 64 + i] = QP * (2 * abs (qcoeff[block * 64 + i]) + 1);
else
rcoeff[block * 64 + i] = QP * (2 * abs (qcoeff[block * 64 + i]) + 1) - 1;
rcoeff[block * 64 + i] = sign (qcoeff[block * 64 + i]) * rcoeff[block * 64 + i];
}
} else
rcoeff[block * 64 + i] = 0;
}
if ((Mode == MODE_INTRA || Mode == MODE_INTRA_Q) && !advanced_intra_coding)
{
/* Intra (except when advanced intra coding is used) */
rcoeff[block * 64] = qcoeff[block * 64] * 8;
}
} else
{
/* No quantizing at all */
for (i = 0; i < 64; i++)
{
rcoeff[block * 64 + i] = qcoeff[block * 64 + i];
}
}
return;
}
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