1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
/*
* Copyright (C) 2007-2008 ARM Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/* ----------------------------------------------------------------
*
*
* File Name: omxVCM4P10_DecodeCoeffsToPairCAVLC.c
* OpenMAX DL: v1.0.2
* Revision: 9641
* Date: Thursday, February 7, 2008
*
*
*
*
* H.264 decode coefficients module
*
*/
#include "omxtypes.h"
#include "armOMX.h"
#include "omxVC.h"
#include "armCOMM.h"
#include "armVC.h"
/**
* Function: omxVCM4P10_DecodeCoeffsToPairCAVLC (6.3.4.1.2)
*
* Description:
* Performs CAVLC decoding and inverse zigzag scan for 4x4 block of
* Intra16x16DCLevel, Intra16x16ACLevel, LumaLevel, and ChromaACLevel. Inverse
* field scan is not supported. The decoded coefficients in the packed
* position-coefficient buffer are stored in reverse zig-zag order, i.e., the
* first buffer element contains the last non-zero postion-coefficient pair of
* the block. Within each position-coefficient pair, the position entry
* indicates the raster-scan position of the coefficient, while the
* coefficient entry contains the coefficient value.
*
* Input Arguments:
*
* ppBitStream -Double pointer to current byte in bit stream buffer
* pOffset - Pointer to current bit position in the byte pointed to by
* *ppBitStream; valid in the range [0,7].
* sMaxNumCoeff - Maximum the number of non-zero coefficients in current
* block
* sVLCSelect - VLC table selector, obtained from the number of non-zero
* coefficients contained in the above and left 4x4 blocks. It is
* equivalent to the variable nC described in H.264 standard table
* 9 5, except its value can t be less than zero.
*
* Output Arguments:
*
* ppBitStream - *ppBitStream is updated after each block is decoded.
* Buffer position (*ppPosCoefBuf) is updated upon return, unless
* there are only zero coefficients in the currently decoded block.
* In this case the caller is expected to bypass the
* transform/dequantization of the empty blocks.
* pOffset - *pOffset is updated after each block is decoded
* pNumCoeff - Pointer to the number of nonzero coefficients in this block
* ppPosCoefBuf - Double pointer to destination residual
* coefficient-position pair buffer
*
* Return Value:
* OMX_Sts_NoErr, if the function runs without error.
*
* OMX_Sts_BadArgErr - bad arguments: if one of the following cases occurs:
* - ppBitStream or pOffset is NULL.
* - ppPosCoefBuf or pNumCoeff is NULL.
* - sMaxNumCoeff is not equal to either 15 or 16.
* - sVLCSelect is less than 0.
*
* OMX_Sts_Err - if one of the following is true:
* - an illegal code is encountered in the bitstream
*
*/
OMXResult omxVCM4P10_DecodeCoeffsToPairCAVLC(
const OMX_U8** ppBitStream,
OMX_S32* pOffset,
OMX_U8* pNumCoeff,
OMX_U8**ppPosCoefbuf,
OMX_INT sVLCSelect,
OMX_INT sMaxNumCoeff
)
{
int nTable;
armRetArgErrIf(ppBitStream==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*ppBitStream==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(pOffset==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*pOffset<0 , OMX_Sts_BadArgErr);
armRetArgErrIf(*pOffset>7 , OMX_Sts_BadArgErr);
armRetArgErrIf(pNumCoeff==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(ppPosCoefbuf==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*ppPosCoefbuf==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(sVLCSelect<0 , OMX_Sts_BadArgErr);
armRetArgErrIf(sMaxNumCoeff<15 , OMX_Sts_BadArgErr);
armRetArgErrIf(sMaxNumCoeff>16 , OMX_Sts_BadArgErr);
/* Find VLC table number */
if (sVLCSelect<2)
{
nTable = 0;
}
else if (sVLCSelect<4)
{
nTable = 1;
}
else if (sVLCSelect<8)
{
nTable = 2;
}
else /* sVLCSelect >= 8 */
{
nTable = 3;
}
return armVCM4P10_DecodeCoeffsToPair(ppBitStream, pOffset, pNumCoeff,
ppPosCoefbuf, nTable, sMaxNumCoeff);
}
|
