omxvcm4p2_quantinvinter_i.c

来自「The OpenMAX DL (Development Layer) APIs 」· C语言 代码 · 共 97 行

/**
 * 
 * File Name:  omxVCM4P2_QuantInvInter_I.c
 * OpenMAX DL: v1.0.2
 * Revision:   10586
 * Date:       Wednesday, March 5, 2008
 * 
 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
 * 
 * 
 *
 * Description:
 * Contains modules for inter inverse Quantization
 * 
 */ 

#include "omxtypes.h"
#include "armOMX.h"
#include "omxVC.h"

#include "armCOMM.h"


/**
 * Function:  omxVCM4P2_QuantInvInter_I   (6.2.5.3.2)
 *
 * Description:
 * Performs the second inverse quantization mode on an intra/inter coded 
 * block. Supports bits_per_pixel = 8. The output coefficients are clipped to 
 * the range [-2048, 2047]. 
 *
 * Input Arguments:
 *   
 *   pSrcDst - pointer to the input (quantized) intra/inter block; must be 
 *            aligned on a 16-byte boundary. 
 *   QP - quantization parameter (quantizer_scale) 
 *   videoComp - video component type of the current block. Takes one of the 
 *            following flags: OMX_VC_LUMINANCE, OMX_VC_CHROMINANCE (intra 
 *            version only). 
 *   shortVideoHeader - binary flag indicating presence of short_video_header 
 *            (intra version only). 
 *
 * Output Arguments:
 *   
 *   pSrcDst - pointer to the output (dequantized) intra/inter block 
 *
 * Return Value:
 *    
 *    OMX_Sts_NoErr - no error 
 *    OMX_Sts_BadArgErr - bad arguments; one or more of the following is 
 *              true: 
 *    -    pSrcDst is NULL 
 *    -    QP <= 0 or QP >=31 
 *    -    videoComp is neither OMX_VC_LUMINANCE nor OMX_VC_CHROMINANCE. 
 *
 */

OMXResult omxVCM4P2_QuantInvInter_I(
     OMX_S16 * pSrcDst,
     OMX_INT QP
	 )
{

    OMX_INT coeffCount, Sign;
    
    /* Argument error checks */
    armRetArgErrIf(pSrcDst == NULL, OMX_Sts_BadArgErr);
    armRetArgErrIf(((QP <= 0) || (QP >= 32)), OMX_Sts_BadArgErr);

    /* Second Inverse quantisation method */
    for (coeffCount = 0; coeffCount < 64; coeffCount++)
    {
        /* check sign */
        Sign =  armSignCheck (pSrcDst[coeffCount]);
              
        /* Quantize the coeff */
        if (QP & 0x1)
        {
            pSrcDst[coeffCount] = (2* armAbs(pSrcDst[coeffCount]) + 1) * QP;
            pSrcDst[coeffCount] *= Sign;
        }
        else
        {
            pSrcDst[coeffCount] = (2* armAbs(pSrcDst[coeffCount]) + 1)
                                                                * QP - 1;
            pSrcDst[coeffCount] *= Sign;
        }
        /* Saturate */
        pSrcDst[coeffCount] = armClip (-2048, 2047, pSrcDst[coeffCount]);
    }
    return OMX_Sts_NoErr;
}

/* End of file */