omxVCM4P2_DecodeBlockCoef_Inter.c revision 78e52bfac041d71ce53b5b13c2abf78af742b09d 
1/*
2 * Copyright (C) 2007-2008 ARM Limited
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 *
16 */
17/**
18 *
19 * File Name:  omxVCM4P2_DecodeBlockCoef_Inter.c
20 * OpenMAX DL: v1.0.2
21 * Revision:   12290
22 * Date:       Wednesday, April 9, 2008
23 *
24 *
25 *
26 *
27 * Description:
28 * Contains modules for inter reconstruction
29 *
30 */
31
32
33#include "omxtypes.h"
34#include "armOMX.h"
35#include "omxVC.h"
36
37#include "armCOMM.h"
38
39
40/**
41 * Function: omxVCM4P2_DecodeBlockCoef_Inter
42 *
43 * Description:
44 * Decodes the INTER block coefficients. Inverse quantization, inversely zigzag
45 * positioning and IDCT, with appropriate clipping on each step, are performed
46 * on the coefficients. The results (residuals) are placed in a contiguous array
47 * of 64 elements. For INTER block, the output buffer holds the residuals for
48 * further reconstruction.
49 *
50 * Remarks:
51 *
52 * Parameters:
53 * [in]	ppBitStream		pointer to the pointer to the current byte in
54 *								the bit stream buffer. There is no boundary
55 *								check for the bit stream buffer.
56 * [in]	pBitOffset		pointer to the bit position in the byte pointed
57 *								to by *ppBitStream. *pBitOffset is valid within
58 *								[0-7]
59 * [in]	QP				quantization parameter
60 * [in] shortVideoHeader    a flag indicating presence of short_video_header;
61 *                           shortVideoHeader==1 indicates using quantization method defined in short
62 *                           video header mode, and shortVideoHeader==0 indicates normail quantization method.
63 * [out] ppBitStream 	*ppBitStream is updated after the block is decoded, so that it points to the
64 *                      current byte in the bit stream buffer.
65 * [out] pBitOffset		*pBitOffset is updated so that it points to the current bit position in the
66 *                      byte pointed by *ppBitStream
67 * [out] pDst			pointer to the decoded residual buffer (a contiguous array of 64 elements of
68 *                      OMX_S16 data type). Must be 16-byte aligned.
69 *
70 * Return Value:
71 * OMX_Sts_NoErr - no error
72 * OMX_Sts_BadArgErr - bad arguments
73 *   - At least one of the following pointers is Null: ppBitStream, *ppBitStream, pBitOffset , pDst
74 *   - At least one of the below case:
75 *   - *pBitOffset exceeds [0,7], QP <= 0;
76 *	 - pDst not 16-byte aligned
77 * OMX_Sts_Err - status error
78 *
79 */
80OMXResult omxVCM4P2_DecodeBlockCoef_Inter(
81     const OMX_U8 ** ppBitStream,
82     OMX_INT * pBitOffset,
83     OMX_S16 * pDst,
84     OMX_INT QP,
85     OMX_INT shortVideoHeader
86)
87{
88    /* 64 elements are needed but to align it to 16 bytes need
89    15 more elements of padding */
90    OMX_S16 tempBuf[79];
91    OMX_S16 *pTempBuf1;
92    OMXResult errorCode;
93    /* Aligning the local buffers */
94    pTempBuf1 = armAlignTo16Bytes(tempBuf);
95
96
97    /* VLD and zigzag */
98    errorCode = omxVCM4P2_DecodeVLCZigzag_Inter(ppBitStream, pBitOffset,
99                                        pTempBuf1,shortVideoHeader);
100    armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode);
101
102    /* Dequantization */
103    errorCode = omxVCM4P2_QuantInvInter_I(
104     pTempBuf1,
105     QP);
106    armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode);
107
108    /* Inverse transform */
109    errorCode = omxVCM4P2_IDCT8x8blk(pTempBuf1, pDst);
110    armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode);
111
112    return OMX_Sts_NoErr;
113}
114
115/* End of file */
116
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118