armVCM4P2_FillVLCBuffer.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:  armVCM4P2_FillVLCBuffer.c
20 * OpenMAX DL: v1.0.2
21 * Revision:   9641
22 * Date:       Thursday, February 7, 2008
23 *
24 *
25 *
26 *
27 * Description:
28 * Contains module for putting VLC bits
29 *
30 */
31
32#include "omxtypes.h"
33#include "armOMX.h"
34
35#include "armVC.h"
36#include "armCOMM.h"
37#include "armCOMM_Bitstream.h"
38
39/**
40 * Function: armVCM4P2_FillVLCBuffer
41 *
42 * Description:
43 * Performs calculating the VLC bits depending on the escape type and insert
44 * the same in the bitstream
45 *
46 * Remarks:
47 *
48 * Parameters:
49 * [in]	 ppBitStream		pointer to the pointer to the current byte in
50 *	                        the bit stream
51 * [in]	 pBitOffset         pointer to the bit position in the byte pointed
52 *                          by *ppBitStream. Valid within 0 to 7
53 * [in]  run                Run value (count of zeros) to be encoded
54 * [in]  level              Level value (non-zero value) to be encoded
55 * [in]  runPlus            Calculated as runPlus = run - (RMAX + 1)
56 * [in]  levelPlus          Calculated as
57 *                          levelPlus = sign(level)*[abs(level) - LMAX]
58 * [in]  fMode              Flag indicating the escape modes
59 * [in]  last               status of the last flag
60 * [in]  maxRunForMultipleEntries
61 *                          The run value after which level will be equal to 1:
62 *                          (considering last and inter/intra status)
63 * [in]  pRunIndexTable     Run Index table defined in
64 *                          armVCM4P2_Huff_Tables_VLC.h
65 * [in]  pVlcTable          VLC table defined in armVCM4P2_Huff_Tables_VLC.h
66 * [out] ppBitStream		*ppBitStream is updated after the block is encoded
67 *                          so that it points to the current byte in the bit
68 *                          stream buffer.
69 * [out] pBitOffset         *pBitOffset is updated so that it points to the
70 *                          current bit position in the byte pointed by
71 *                          *ppBitStream.
72 *
73 * Return Value:
74 * Standard OMXResult result. See enumeration for possible result codes.
75 *
76 */
77
78OMXResult armVCM4P2_FillVLCBuffer (
79              OMX_U8 **ppBitStream,
80              OMX_INT * pBitOffset,
81              OMX_U32 run,
82              OMX_S16 level,
83			  OMX_U32 runPlus,
84              OMX_S16 levelPlus,
85              OMX_U8  fMode,
86			  OMX_U8  last,
87              OMX_U8  maxRunForMultipleEntries,
88              const OMX_U8  *pRunIndexTable,
89              const ARM_VLC32 *pVlcTable
90)
91{
92    OMX_INT tempIndex;
93	OMX_U32 tempRun = run, sign = 0;
94    OMX_S16 tempLevel = level;
95
96    /* Escape sequence addition */
97    if (fMode == 1)
98    {
99        armPackBits(ppBitStream, pBitOffset, 3, 7);
100        armPackBits(ppBitStream, pBitOffset, 0, 1);
101		tempLevel = levelPlus;
102
103    }
104    else if(fMode == 2)
105    {
106        armPackBits(ppBitStream, pBitOffset, 3, 7);
107        armPackBits(ppBitStream, pBitOffset, 2, 2);
108		tempRun = runPlus;
109    }
110    else if (fMode == 3)
111    {
112        armPackBits(ppBitStream, pBitOffset, 3, 7);
113        armPackBits(ppBitStream, pBitOffset, 3, 2);
114    }
115    else if (fMode == 4)
116    {
117        armPackBits(ppBitStream, pBitOffset, 3, 7);
118        armPackBits(ppBitStream, pBitOffset, (OMX_U32)last, 1);
119		armPackBits(ppBitStream, pBitOffset, tempRun, 6);
120		if((tempLevel != 0) && (tempLevel != -128))
121		{
122		    armPackBits(ppBitStream, pBitOffset,
123			   (OMX_U32) tempLevel, 8);
124		}
125		return OMX_Sts_NoErr;
126    }
127
128    if (tempLevel < 0)
129    {
130        sign = 1;
131        tempLevel = armAbs(tempLevel);
132    }
133    /* Putting VLC bits in the stream */
134	if (fMode < 3)
135	{
136		if (tempRun > maxRunForMultipleEntries)
137		{
138			tempIndex = pRunIndexTable [maxRunForMultipleEntries + 1] +
139						(tempRun - maxRunForMultipleEntries - 1);
140		}
141		else
142		{
143			tempIndex = pRunIndexTable [tempRun] + (tempLevel -1);
144		}
145
146		armPackVLC32 (ppBitStream, pBitOffset,
147					  pVlcTable [tempIndex]);
148		armPackBits(ppBitStream, pBitOffset, (OMX_U32)sign, 1);
149	}
150    else
151	{
152		if (sign)
153		{
154			tempLevel = -tempLevel;
155		}
156		tempRun  = run;
157		armPackBits(ppBitStream, pBitOffset, (OMX_U32)last, 1);
158		armPackBits(ppBitStream, pBitOffset, tempRun, 6);
159		armPackBits(ppBitStream, pBitOffset, 1, 1);
160		armPackBits(ppBitStream, pBitOffset,
161			   (OMX_U32) tempLevel, 12);
162		armPackBits(ppBitStream, pBitOffset, 1, 1);
163	}
164    return OMX_Sts_NoErr;
165}
166
167/*End of File*/
168
169