omxVCM4P2_DecodeVLCZigzag_Inter.c revision 0c1bc742181ded4930842b46e9507372f0b1b963 
1/**
2 *
3 * File Name:  omxVCM4P2_DecodeVLCZigzag_Inter.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 zigzag scanning and VLC decoding
14 * for inter block.
15 *
16 */
17
18#include "omxtypes.h"
19#include "armOMX.h"
20#include "omxVC.h"
21
22#include "armVC.h"
23#include "armCOMM_Bitstream.h"
24#include "armCOMM.h"
25#include "armVCM4P2_Huff_Tables_VLC.h"
26#include "armVCM4P2_ZigZag_Tables.h"
27
28
29
30/**
31 * Function:  omxVCM4P2_DecodeVLCZigzag_Inter   (6.2.5.2.3)
32 *
33 * Description:
34 * Performs VLC decoding and inverse zigzag scan for one inter-coded block.
35 *
36 * Input Arguments:
37 *
38 *   ppBitStream - double pointer to the current byte in the stream buffer
39 *   pBitOffset - pointer to the next available bit in the current stream
40 *            byte referenced by *ppBitStream. The parameter *pBitOffset is
41 *            valid within the range [0-7].
42 *   shortVideoHeader - binary flag indicating presence of
43 *            short_video_header; escape modes 0-3 are used if
44 *            shortVideoHeader==0, and escape mode 4 is used when
45 *            shortVideoHeader==1.
46 *
47 * Output Arguments:
48 *
49 *   ppBitStream - *ppBitStream is updated after the block is decoded such
50 *            that it points to the current byte in the stream buffer
51 *   pBitOffset - *pBitOffset is updated after decoding such that it points
52 *            to the next available bit in the stream byte referenced by
53 *            *ppBitStream
54 *   pDst - pointer to the coefficient buffer of current block; must be
55 *            4-byte aligned.
56 *
57 * Return Value:
58 *
59 *    OMX_Sts_BadArgErr - bad arguments:
60 *    -    At least one of the following pointers is NULL:
61 *         ppBitStream, *ppBitStream, pBitOffset, pDst
62 *    -    pDst is not 4-byte aligned
63 *    -   *pBitOffset exceeds [0,7]
64 *    OMX_Sts_Err - status error, if:
65 *    -    At least one mark bit is equal to zero
66 *    -    Encountered an illegal stream code that cannot be found in the VLC table
67 *    -    Encountered an illegal code in the VLC FLC table
68 *    -    The number of coefficients is greater than 64
69 *
70 */
71
72OMXResult omxVCM4P2_DecodeVLCZigzag_Inter(
73     const OMX_U8 ** ppBitStream,
74     OMX_INT * pBitOffset,
75     OMX_S16 * pDst,
76     OMX_INT shortVideoHeader
77)
78{
79    OMX_U8  last,start = 0;
80    const OMX_U8  *pZigzagTable = armVCM4P2_aClassicalZigzagScan;
81    OMXResult errorCode;
82
83    /* Argument error checks */
84    armRetArgErrIf(ppBitStream == NULL, OMX_Sts_BadArgErr);
85    armRetArgErrIf(*ppBitStream == NULL, OMX_Sts_BadArgErr);
86    armRetArgErrIf(pBitOffset == NULL, OMX_Sts_BadArgErr);
87    armRetArgErrIf(pDst == NULL, OMX_Sts_BadArgErr);
88    armRetArgErrIf(!armIs4ByteAligned(pDst), OMX_Sts_BadArgErr);
89
90    errorCode = armVCM4P2_GetVLCBits (
91              ppBitStream,
92              pBitOffset,
93			  pDst,
94			  shortVideoHeader,
95              start,
96			  &last,
97			  11,
98			  42,
99			   2,
100			   5,
101              armVCM4P2_InterL0RunIdx,
102              armVCM4P2_InterVlcL0,
103			  armVCM4P2_InterL1RunIdx,
104              armVCM4P2_InterVlcL1,
105              armVCM4P2_InterL0LMAX,
106              armVCM4P2_InterL1LMAX,
107              armVCM4P2_InterL0RMAX,
108              armVCM4P2_InterL1RMAX,
109              pZigzagTable );
110    armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode);
111
112    if (last == 0)
113    {
114        return OMX_Sts_Err;
115    }
116    return OMX_Sts_NoErr;
117}
118
119/* End of file */
120
121