Home | History | Annotate | Download | only in src 
      1 /**
      2  *
      3  * File Name:  omxVCM4P2_QuantInter_I.c
      4  * OpenMAX DL: v1.0.2
      5  * Revision:   9641
      6  * Date:       Thursday, February 7, 2008
      7  *
      8  * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
      9  *
     10  *
     11  *
     12  * Description:
     13  * Contains modules for inter Quantization
     14  *
     15  */
     16 
     17 #include "omxtypes.h"
     18 #include "armOMX.h"
     19 #include "omxVC.h"
     20 
     21 #include "armCOMM.h"
     22 
     23 /**
     24  * Function:  omxVCM4P2_QuantInter_I   (6.2.4.4.3)
     25  *
     26  * Description:
     27  * Performs quantization on an inter coefficient block; supports
     28  * bits_per_pixel == 8.
     29  *
     30  * Input Arguments:
     31  *
     32  *   pSrcDst - pointer to the input inter block coefficients; must be aligned
     33  *            on a 16-byte boundary.
     34  *   QP - quantization parameter (quantizer_scale)
     35  *   shortVideoHeader - binary flag indicating presence of short_video_header;
     36  *            shortVideoHeader==1 selects linear intra DC mode, and
     37  *            shortVideoHeader==0 selects non linear intra DC mode.
     38  *
     39  * Output Arguments:
     40  *
     41  *   pSrcDst - pointer to the output (quantized) interblock coefficients.
     42  *            When shortVideoHeader==1, AC coefficients are saturated on the
     43  *            interval [-127, 127], and DC coefficients are saturated on the
     44  *            interval [1, 254].  When shortVideoHeader==0, AC coefficients
     45  *            are saturated on the interval [-2047, 2047].
     46  *
     47  * Return Value:
     48  *
     49  *    OMX_Sts_NoErr - no error
     50  *    OMX_Sts_BadArgErr - bad arguments:
     51  *    -    pSrcDst is NULL.
     52  *    -    QP <= 0 or QP >= 32.
     53  *
     54  */
     55 
     56 OMXResult omxVCM4P2_QuantInter_I(
     57      OMX_S16 * pSrcDst,
     58      OMX_U8 QP,
     59 	 OMX_INT shortVideoHeader
     60 )
     61 {
     62 
     63     /* Definitions and Initializations*/
     64     OMX_INT coeffCount;
     65     OMX_INT fSign;
     66     OMX_INT maxClpAC = 0, minClpAC = 0;
     67     OMX_INT maxClpDC = 0, minClpDC = 0;
     68 
     69     /* Argument error checks */
     70     armRetArgErrIf(pSrcDst == NULL, OMX_Sts_BadArgErr);
     71     armRetArgErrIf(((QP <= 0) || (QP >= 32)), OMX_Sts_BadArgErr);
     72    /* One argument check is delayed until we have ascertained that  */
     73    /* pQMatrix is not NULL.                                         */
     74 
     75     /* Set the Clip Range based on SVH on/off */
     76     if(shortVideoHeader == 1)
     77     {
     78        maxClpDC = 254;
     79        minClpDC = 1;
     80        maxClpAC = 127;
     81        minClpAC = -127;
     82     }
     83     else
     84     {
     85         maxClpDC = 2047;
     86         minClpDC = -2047;
     87         maxClpAC = 2047;
     88         minClpAC = -2047;
     89     }
     90 
     91     /* Second Inverse quantisation method */
     92     for (coeffCount = 0; coeffCount < 64; coeffCount++)
     93     {
     94         fSign =  armSignCheck (pSrcDst[coeffCount]);
     95         pSrcDst[coeffCount] = (armAbs(pSrcDst[coeffCount])
     96                               - (QP/2))/(2 * QP);
     97         pSrcDst[coeffCount] *= fSign;
     98 
     99         /* Clip */
    100         if (coeffCount == 0)
    101         {
    102            pSrcDst[coeffCount] =
    103            (OMX_S16) armClip (minClpDC, maxClpDC, pSrcDst[coeffCount]);
    104         }
    105         else
    106         {
    107            pSrcDst[coeffCount] =
    108            (OMX_S16) armClip (minClpAC, maxClpAC, pSrcDst[coeffCount]);
    109         }
    110     }
    111     return OMX_Sts_NoErr;
    112 
    113 }
    114 
    115 /* End of file */
    116 
    117 
    118