1 /** 2 * 3 * File Name: armCOMM_Bitstream.h 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 * File: armCOMM_Bitstream.h 13 * Brief: Declares common API's/Data types used across the OpenMax Encoders/Decoders. 14 * 15 */ 16 17 #ifndef _armCodec_H_ 18 #define _armCodec_H_ 19 20 #include "omxtypes.h" 21 22 typedef struct { 23 OMX_U8 codeLen; 24 OMX_U32 codeWord; 25 } ARM_VLC32; 26 27 /* The above should be renamed as "ARM_VLC32" */ 28 29 /** 30 * Function: armLookAheadBits() 31 * 32 * Description: 33 * Get the next N bits from the bitstream without advancing the bitstream pointer 34 * 35 * Parameters: 36 * [in] **ppBitStream 37 * [in] *pOffset 38 * [in] N=1...32 39 * 40 * Returns Value 41 */ 42 43 OMX_U32 armLookAheadBits(const OMX_U8 **ppBitStream, OMX_INT *pOffset, OMX_INT N); 44 45 /** 46 * Function: armGetBits() 47 * 48 * Description: 49 * Read N bits from the bitstream 50 * 51 * Parameters: 52 * [in] *ppBitStream 53 * [in] *pOffset 54 * [in] N=1..32 55 * 56 * [out] *ppBitStream 57 * [out] *pOffset 58 * Returns Value 59 */ 60 61 OMX_U32 armGetBits(const OMX_U8 **ppBitStream, OMX_INT *pOffset, OMX_INT N); 62 63 /** 64 * Function: armByteAlign() 65 * 66 * Description: 67 * Align the pointer *ppBitStream to the next byte boundary 68 * 69 * Parameters: 70 * [in] *ppBitStream 71 * [in] *pOffset 72 * 73 * [out] *ppBitStream 74 * [out] *pOffset 75 * 76 **/ 77 78 OMXVoid armByteAlign(const OMX_U8 **ppBitStream,OMX_INT *pOffset); 79 80 /** 81 * Function: armSkipBits() 82 * 83 * Description: 84 * Skip N bits from the value at *ppBitStream 85 * 86 * Parameters: 87 * [in] *ppBitStream 88 * [in] *pOffset 89 * [in] N 90 * 91 * [out] *ppBitStream 92 * [out] *pOffset 93 * 94 **/ 95 96 OMXVoid armSkipBits(const OMX_U8 **ppBitStream,OMX_INT *pOffset,OMX_INT N); 97 98 /*************************************** 99 * Variable bit length Decode 100 ***************************************/ 101 102 /** 103 * Function: armUnPackVLC32() 104 * 105 * Description: 106 * Variable length decode of variable length symbol (max size 32 bits) read from 107 * the bit stream pointed by *ppBitStream at *pOffset by using the table 108 * pointed by pCodeBook 109 * 110 * Parameters: 111 * [in] **ppBitStream 112 * [in] *pOffset 113 * [in] pCodeBook 114 * 115 * [out] **ppBitStream 116 * [out] *pOffset 117 * 118 * Returns : Code Book Index if successfull. 119 * : "ARM_NO_CODEBOOK_INDEX = 0xFFFF" if search fails. 120 **/ 121 122 #define ARM_NO_CODEBOOK_INDEX (OMX_U16)(0xFFFF) 123 124 OMX_U16 armUnPackVLC32( 125 const OMX_U8 **ppBitStream, 126 OMX_INT *pOffset, 127 const ARM_VLC32 *pCodeBook 128 ); 129 130 /*************************************** 131 * Fixed bit length Encode 132 ***************************************/ 133 134 /** 135 * Function: armPackBits 136 * 137 * Description: 138 * Pack a VLC code word into the bitstream 139 * 140 * Remarks: 141 * 142 * Parameters: 143 * [in] ppBitStream pointer to the pointer to the current byte 144 * in the bit stream. 145 * [in] pOffset pointer to the bit position in the byte 146 * pointed by *ppBitStream. Valid within 0 147 * to 7. 148 * [in] codeWord Code word that need to be inserted in to the 149 * bitstream 150 * [in] codeLength Length of the code word valid range 1...32 151 * 152 * [out] ppBitStream *ppBitStream is updated after the block is encoded, 153 * so that it points to the current byte in the bit 154 * stream buffer. 155 * [out] pBitOffset *pBitOffset is updated so that it points to the 156 * current bit position in the byte pointed by 157 * *ppBitStream. 158 * 159 * Return Value: 160 * Standard OMX_RESULT result. See enumeration for possible result codes. 161 * 162 */ 163 164 OMXResult armPackBits ( 165 OMX_U8 **ppBitStream, 166 OMX_INT *pOffset, 167 OMX_U32 codeWord, 168 OMX_INT codeLength 169 ); 170 171 /*************************************** 172 * Variable bit length Encode 173 ***************************************/ 174 175 /** 176 * Function: armPackVLC32 177 * 178 * Description: 179 * Pack a VLC code word into the bitstream 180 * 181 * Remarks: 182 * 183 * Parameters: 184 * [in] ppBitStream pointer to the pointer to the current byte 185 * in the bit stream. 186 * [in] pBitOffset pointer to the bit position in the byte 187 * pointed by *ppBitStream. Valid within 0 188 * to 7. 189 * [in] code VLC code word that need to be inserted in to the 190 * bitstream 191 * 192 * [out] ppBitStream *ppBitStream is updated after the block is encoded, 193 * so that it points to the current byte in the bit 194 * stream buffer. 195 * [out] pBitOffset *pBitOffset is updated so that it points to the 196 * current bit position in the byte pointed by 197 * *ppBitStream. 198 * 199 * Return Value: 200 * Standard OMX_RESULT result. See enumeration for possible result codes. 201 * 202 */ 203 204 OMXResult armPackVLC32 ( 205 OMX_U8 **ppBitStream, 206 OMX_INT *pBitOffset, 207 ARM_VLC32 code 208 ); 209 210 #endif /*_armCodec_H_*/ 211 212 /*End of File*/ 213
