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: armCOMM_Bitstream.h 20 * OpenMAX DL: v1.0.2 21 * Revision: 12290 22 * Date: Wednesday, April 9, 2008 23 * 24 * 25 * 26 * 27 * File: armCOMM_Bitstream.h 28 * Brief: Declares common API's/Data types used across the OpenMax Encoders/Decoders. 29 * 30 */ 31 32 #ifndef _armCodec_H_ 33 #define _armCodec_H_ 34 35 #include "omxtypes.h" 36 37 typedef struct { 38 OMX_U8 codeLen; 39 OMX_U32 codeWord; 40 } ARM_VLC32; 41 42 /* The above should be renamed as "ARM_VLC32" */ 43 44 /** 45 * Function: armLookAheadBits() 46 * 47 * Description: 48 * Get the next N bits from the bitstream without advancing the bitstream pointer 49 * 50 * Parameters: 51 * [in] **ppBitStream 52 * [in] *pOffset 53 * [in] N=1...32 54 * 55 * Returns Value 56 */ 57 58 OMX_U32 armLookAheadBits(const OMX_U8 **ppBitStream, OMX_INT *pOffset, OMX_INT N); 59 60 /** 61 * Function: armGetBits() 62 * 63 * Description: 64 * Read N bits from the bitstream 65 * 66 * Parameters: 67 * [in] *ppBitStream 68 * [in] *pOffset 69 * [in] N=1..32 70 * 71 * [out] *ppBitStream 72 * [out] *pOffset 73 * Returns Value 74 */ 75 76 OMX_U32 armGetBits(const OMX_U8 **ppBitStream, OMX_INT *pOffset, OMX_INT N); 77 78 /** 79 * Function: armByteAlign() 80 * 81 * Description: 82 * Align the pointer *ppBitStream to the next byte boundary 83 * 84 * Parameters: 85 * [in] *ppBitStream 86 * [in] *pOffset 87 * 88 * [out] *ppBitStream 89 * [out] *pOffset 90 * 91 **/ 92 93 OMXVoid armByteAlign(const OMX_U8 **ppBitStream,OMX_INT *pOffset); 94 95 /** 96 * Function: armSkipBits() 97 * 98 * Description: 99 * Skip N bits from the value at *ppBitStream 100 * 101 * Parameters: 102 * [in] *ppBitStream 103 * [in] *pOffset 104 * [in] N 105 * 106 * [out] *ppBitStream 107 * [out] *pOffset 108 * 109 **/ 110 111 OMXVoid armSkipBits(const OMX_U8 **ppBitStream,OMX_INT *pOffset,OMX_INT N); 112 113 /*************************************** 114 * Variable bit length Decode 115 ***************************************/ 116 117 /** 118 * Function: armUnPackVLC32() 119 * 120 * Description: 121 * Variable length decode of variable length symbol (max size 32 bits) read from 122 * the bit stream pointed by *ppBitStream at *pOffset by using the table 123 * pointed by pCodeBook 124 * 125 * Parameters: 126 * [in] **ppBitStream 127 * [in] *pOffset 128 * [in] pCodeBook 129 * 130 * [out] **ppBitStream 131 * [out] *pOffset 132 * 133 * Returns : Code Book Index if successfull. 134 * : "ARM_NO_CODEBOOK_INDEX = 0xFFFF" if search fails. 135 **/ 136 137 #define ARM_NO_CODEBOOK_INDEX (OMX_U16)(0xFFFF) 138 139 OMX_U16 armUnPackVLC32( 140 const OMX_U8 **ppBitStream, 141 OMX_INT *pOffset, 142 const ARM_VLC32 *pCodeBook 143 ); 144 145 /*************************************** 146 * Fixed bit length Encode 147 ***************************************/ 148 149 /** 150 * Function: armPackBits 151 * 152 * Description: 153 * Pack a VLC code word into the bitstream 154 * 155 * Remarks: 156 * 157 * Parameters: 158 * [in] ppBitStream pointer to the pointer to the current byte 159 * in the bit stream. 160 * [in] pOffset pointer to the bit position in the byte 161 * pointed by *ppBitStream. Valid within 0 162 * to 7. 163 * [in] codeWord Code word that need to be inserted in to the 164 * bitstream 165 * [in] codeLength Length of the code word valid range 1...32 166 * 167 * [out] ppBitStream *ppBitStream is updated after the block is encoded, 168 * so that it points to the current byte in the bit 169 * stream buffer. 170 * [out] pBitOffset *pBitOffset is updated so that it points to the 171 * current bit position in the byte pointed by 172 * *ppBitStream. 173 * 174 * Return Value: 175 * Standard OMX_RESULT result. See enumeration for possible result codes. 176 * 177 */ 178 179 OMXResult armPackBits ( 180 OMX_U8 **ppBitStream, 181 OMX_INT *pOffset, 182 OMX_U32 codeWord, 183 OMX_INT codeLength 184 ); 185 186 /*************************************** 187 * Variable bit length Encode 188 ***************************************/ 189 190 /** 191 * Function: armPackVLC32 192 * 193 * Description: 194 * Pack a VLC code word into the bitstream 195 * 196 * Remarks: 197 * 198 * Parameters: 199 * [in] ppBitStream pointer to the pointer to the current byte 200 * in the bit stream. 201 * [in] pBitOffset pointer to the bit position in the byte 202 * pointed by *ppBitStream. Valid within 0 203 * to 7. 204 * [in] code VLC code word that need to be inserted in to the 205 * bitstream 206 * 207 * [out] ppBitStream *ppBitStream is updated after the block is encoded, 208 * so that it points to the current byte in the bit 209 * stream buffer. 210 * [out] pBitOffset *pBitOffset is updated so that it points to the 211 * current bit position in the byte pointed by 212 * *ppBitStream. 213 * 214 * Return Value: 215 * Standard OMX_RESULT result. See enumeration for possible result codes. 216 * 217 */ 218 219 OMXResult armPackVLC32 ( 220 OMX_U8 **ppBitStream, 221 OMX_INT *pBitOffset, 222 ARM_VLC32 code 223 ); 224 225 #endif /*_armCodec_H_*/ 226 227 /*End of File*/ 228
