omxVCM4P2_QuantIntra_I.c revision 0c1bc742181ded4930842b46e9507372f0b1b963 
1/**
2 *
3 * File Name:  omxVCM4P2_QuantIntra_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 intra Quantization
14 *
15 */
16
17#include "omxtypes.h"
18#include "armOMX.h"
19#include "omxVC.h"
20
21#include "armCOMM.h"
22/**
23 * Function:  omxVCM4P2_QuantIntra_I   (6.2.4.4.2)
24 *
25 * Description:
26 * Performs quantization on intra block coefficients. This function supports
27 * bits_per_pixel == 8.
28 *
29 * Input Arguments:
30 *
31 *   pSrcDst - pointer to the input intra block coefficients; must be aligned
32 *            on a 16-byte boundary.
33 *   QP - quantization parameter (quantizer_scale).
34 *   blockIndex - block index indicating the component type and position,
35 *            valid in the range 0 to 5, as defined in [ISO14496-2], subclause
36 *            6.1.3.8.
37 *   shortVideoHeader - binary flag indicating presence of
38 *            short_video_header; shortVideoHeader==1 selects linear intra DC
39 *            mode, and shortVideoHeader==0 selects non linear intra DC mode.
40 *
41 * Output Arguments:
42 *
43 *   pSrcDst - pointer to the output (quantized) interblock coefficients.
44 *            When shortVideoHeader==1, AC coefficients are saturated on the
45 *            interval [-127, 127], and DC coefficients are saturated on the
46 *            interval [1, 254].  When shortVideoHeader==0, AC coefficients
47 *            are saturated on the interval [-2047, 2047].
48 *
49 * Return Value:
50 *
51 *    OMX_Sts_NoErr - no error
52 *    OMX_Sts_BadArgErr - bad arguments:
53 *    -    pSrcDst is NULL.
54 *    -    blockIndex < 0 or blockIndex >= 10
55 *    -    QP <= 0 or QP >= 32.
56 *
57 */
58
59OMXResult omxVCM4P2_QuantIntra_I(
60     OMX_S16 * pSrcDst,
61     OMX_U8 QP,
62     OMX_INT blockIndex,
63	 OMX_INT shortVideoHeader
64 )
65{
66
67    /* Definitions and Initializations*/
68    /* Initialized to remove compilation error */
69    OMX_INT dcScaler = 0, coeffCount,fSign;
70    OMX_INT maxClpAC, minClpAC;
71
72    /* Argument error checks */
73    armRetArgErrIf(pSrcDst == NULL, OMX_Sts_BadArgErr);
74    armRetArgErrIf(((blockIndex < 0) || (blockIndex >= 10)), OMX_Sts_BadArgErr);
75    armRetArgErrIf(((QP <= 0) || (QP >= 32)), OMX_Sts_BadArgErr);
76   /* One argument check is delayed until we have ascertained that  */
77   /* pQMatrix is not NULL.                                         */
78
79
80    /* Set the Clip Range based on SVH on/off */
81    if(shortVideoHeader == 1)
82    {
83        maxClpAC = 127;
84        minClpAC = -127;
85        dcScaler = 8;
86        /* Dequant the DC value, this applies to both the methods */
87        pSrcDst[0] = armIntDivAwayFromZero (pSrcDst[0], dcScaler);
88
89        /* Clip between 1 and 254 */
90        pSrcDst[0] = (OMX_S16) armClip (1, 254, pSrcDst[0]);
91    }
92    else
93    {
94        maxClpAC = 2047;
95        minClpAC = -2047;
96        /* Calculate the DC scaler value */
97        if ((blockIndex  < 4) || (blockIndex  > 5))
98        {
99            if (QP >= 1 && QP <= 4)
100            {
101                dcScaler = 8;
102            }
103            else if (QP >= 5 && QP <= 8)
104            {
105                dcScaler = 2 * QP;
106            }
107            else if (QP >= 9 && QP <= 24)
108            {
109                dcScaler = QP + 8;
110            }
111            else
112            {
113                dcScaler = (2 * QP) - 16;
114            }
115        }
116        else if (blockIndex < 6)
117        {
118            if (QP >= 1 && QP <= 4)
119            {
120                dcScaler = 8;
121            }
122            else if (QP >= 5 && QP <= 24)
123            {
124                dcScaler = (QP + 13)/2;
125            }
126            else
127            {
128                dcScaler = QP - 6;
129            }
130        }
131
132        /* Dequant the DC value, this applies to both the methods */
133        pSrcDst[0] = armIntDivAwayFromZero (pSrcDst[0], dcScaler);
134    }
135
136    /* Second Inverse quantisation method */
137    for (coeffCount = 1; coeffCount < 64; coeffCount++)
138    {
139        fSign =  armSignCheck (pSrcDst[coeffCount]);
140        pSrcDst[coeffCount] = armAbs(pSrcDst[coeffCount])/(2 * QP);
141        pSrcDst[coeffCount] *= fSign;
142
143        /* Clip */
144        pSrcDst[coeffCount] =
145        (OMX_S16) armClip (minClpAC, maxClpAC, pSrcDst[coeffCount]);
146    }
147    return OMX_Sts_NoErr;
148
149}
150
151/* End of file */
152
153
154