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| 1 | /*! | ||
| 2 | * \copy | ||
| 3 | * Copyright (c) 2013, Cisco Systems | ||
| 4 | * All rights reserved. | ||
| 5 | * | ||
| 6 | * Redistribution and use in source and binary forms, with or without | ||
| 7 | * modification, are permitted provided that the following conditions | ||
| 8 | * are met: | ||
| 9 | * | ||
| 10 | * * Redistributions of source code must retain the above copyright | ||
| 11 | * notice, this list of conditions and the following disclaimer. | ||
| 12 | * | ||
| 13 | * * Redistributions in binary form must reproduce the above copyright | ||
| 14 | * notice, this list of conditions and the following disclaimer in | ||
| 15 | * the documentation and/or other materials provided with the | ||
| 16 | * distribution. | ||
| 17 | * | ||
| 18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
| 19 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
| 20 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | ||
| 21 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | ||
| 22 | * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | ||
| 23 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | ||
| 24 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | ||
| 25 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | ||
| 26 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | ||
| 27 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | ||
| 28 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
| 29 | * POSSIBILITY OF SUCH DAMAGE. | ||
| 30 | * | ||
| 31 | * cabac_decoder.cpp: deals with cabac state transition and related functions | ||
| 32 | */ | ||
| 33 | #include "cabac_decoder.h" | ||
| 34 | namespace WelsDec { | ||
| 35 | static const int16_t g_kMvdBinPos2Ctx [8] = {0, 1, 2, 3, 3, 3, 3, 3}; | ||
| 36 | |||
| 37 | void WelsCabacGlobalInit (PWelsDecoderContext pCtx) { | ||
| 38 | for (int32_t iModel = 0; iModel < 4; iModel++) { | ||
| 39 | for (int32_t iQp = 0; iQp <= WELS_QP_MAX; iQp++) | ||
| 40 | for (int32_t iIdx = 0; iIdx < WELS_CONTEXT_COUNT; iIdx++) { | ||
| 41 | int32_t m = g_kiCabacGlobalContextIdx[iIdx][iModel][0]; | ||
| 42 | int32_t n = g_kiCabacGlobalContextIdx[iIdx][iModel][1]; | ||
| 43 | int32_t iPreCtxState = WELS_CLIP3 ((((m * iQp) >> 4) + n), 1, 126); | ||
| 44 | uint8_t uiValMps = 0; | ||
| 45 | uint8_t uiStateIdx = 0; | ||
| 46 | if (iPreCtxState <= 63) { | ||
| 47 | uiStateIdx = 63 - iPreCtxState; | ||
| 48 | uiValMps = 0; | ||
| 49 | } else { | ||
| 50 | uiStateIdx = iPreCtxState - 64; | ||
| 51 | uiValMps = 1; | ||
| 52 | } | ||
| 53 | pCtx->sWelsCabacContexts[iModel][iQp][iIdx].uiState = uiStateIdx; | ||
| 54 | pCtx->sWelsCabacContexts[iModel][iQp][iIdx].uiMPS = uiValMps; | ||
| 55 | } | ||
| 56 | } | ||
| 57 | pCtx->bCabacInited = true; | ||
| 58 | } | ||
| 59 | |||
| 60 | // ------------------- 1. context initialization | ||
| 61 | void WelsCabacContextInit (PWelsDecoderContext pCtx, uint8_t eSliceType, int32_t iCabacInitIdc, int32_t iQp) { | ||
| 62 | int32_t iIdx = pCtx->eSliceType == WelsCommon::I_SLICE ? 0 : iCabacInitIdc + 1; | ||
| 63 | if (!pCtx->bCabacInited) { | ||
| 64 | WelsCabacGlobalInit (pCtx); | ||
| 65 | } | ||
| 66 | memcpy (pCtx->pCabacCtx, pCtx->sWelsCabacContexts[iIdx][iQp], | ||
| 67 | WELS_CONTEXT_COUNT * sizeof (SWelsCabacCtx)); | ||
| 68 | } | ||
| 69 | |||
| 70 | // ------------------- 2. decoding Engine initialization | ||
| 71 | int32_t InitCabacDecEngineFromBS (PWelsCabacDecEngine pDecEngine, PBitStringAux pBsAux) { | ||
| 72 | int32_t iRemainingBits = - pBsAux->iLeftBits; //pBsAux->iLeftBits < 0 | ||
| 73 | int32_t iRemainingBytes = (iRemainingBits >> 3) + 2; //+2: indicating the pre-read 2 bytes | ||
| 74 | uint8_t* pCurr; | ||
| 75 | |||
| 76 | pCurr = pBsAux->pCurBuf - iRemainingBytes; | ||
| 77 | if(pCurr >= (pBsAux->pEndBuf - 1)) { | ||
| 78 | return ERR_INFO_INVALID_ACCESS; | ||
| 79 | } | ||
| 80 | pDecEngine->uiOffset = ((pCurr[0] << 16) | (pCurr[1] << 8) | pCurr[2]); | ||
| 81 | pDecEngine->uiOffset <<= 16; | ||
| 82 | pDecEngine->uiOffset |= (pCurr[3] << 8) | pCurr[4]; | ||
| 83 | pDecEngine->iBitsLeft = 31; | ||
| 84 | pDecEngine->pBuffCurr = pCurr + 5; | ||
| 85 | |||
| 86 | pDecEngine->uiRange = WELS_CABAC_HALF; | ||
| 87 | pDecEngine->pBuffStart = pBsAux->pStartBuf; | ||
| 88 | pDecEngine->pBuffEnd = pBsAux->pEndBuf; | ||
| 89 | pBsAux->iLeftBits = 0; | ||
| 90 | return ERR_NONE; | ||
| 91 | } | ||
| 92 | |||
| 93 | void RestoreCabacDecEngineToBS (PWelsCabacDecEngine pDecEngine, PBitStringAux pBsAux) { | ||
| 94 | //CABAC decoding finished, changing to SBitStringAux | ||
| 95 | pDecEngine->pBuffCurr -= (pDecEngine->iBitsLeft >> 3); | ||
| 96 | pDecEngine->iBitsLeft = 0; //pcm_alignment_zero_bit in CABAC | ||
| 97 | pBsAux->iLeftBits = 0; | ||
| 98 | pBsAux->pStartBuf = pDecEngine->pBuffStart; | ||
| 99 | pBsAux->pCurBuf = pDecEngine->pBuffCurr; | ||
| 100 | pBsAux->uiCurBits = 0; | ||
| 101 | pBsAux->iIndex = 0; | ||
| 102 | } | ||
| 103 | |||
| 104 | // ------------------- 3. actual decoding | ||
| 105 | int32_t Read32BitsCabac (PWelsCabacDecEngine pDecEngine, uint32_t& uiValue, int32_t& iNumBitsRead) { | ||
| 106 | intX_t iLeftBytes = pDecEngine->pBuffEnd - pDecEngine->pBuffCurr; | ||
| 107 | iNumBitsRead = 0; | ||
| 108 | uiValue = 0; | ||
| 109 | if (iLeftBytes <= 0) { | ||
| 110 | return ERR_CABAC_NO_BS_TO_READ; | ||
| 111 | } | ||
| 112 | switch (iLeftBytes) { | ||
| 113 | case 3: | ||
| 114 | uiValue = ((pDecEngine->pBuffCurr[0]) << 16 | (pDecEngine->pBuffCurr[1]) << 8 | (pDecEngine->pBuffCurr[2])); | ||
| 115 | pDecEngine->pBuffCurr += 3; | ||
| 116 | iNumBitsRead = 24; | ||
| 117 | break; | ||
| 118 | case 2: | ||
| 119 | uiValue = ((pDecEngine->pBuffCurr[0]) << 8 | (pDecEngine->pBuffCurr[1])); | ||
| 120 | pDecEngine->pBuffCurr += 2; | ||
| 121 | iNumBitsRead = 16; | ||
| 122 | break; | ||
| 123 | case 1: | ||
| 124 | uiValue = pDecEngine->pBuffCurr[0]; | ||
| 125 | pDecEngine->pBuffCurr += 1; | ||
| 126 | iNumBitsRead = 8; | ||
| 127 | break; | ||
| 128 | default: | ||
| 129 | uiValue = ((pDecEngine->pBuffCurr[0] << 24) | (pDecEngine->pBuffCurr[1]) << 16 | (pDecEngine->pBuffCurr[2]) << 8 | | ||
| 130 | (pDecEngine->pBuffCurr[3])); | ||
| 131 | pDecEngine->pBuffCurr += 4; | ||
| 132 | iNumBitsRead = 32; | ||
| 133 | break; | ||
| 134 | } | ||
| 135 | return ERR_NONE; | ||
| 136 | } | ||
| 137 | |||
| 138 | int32_t DecodeBinCabac (PWelsCabacDecEngine pDecEngine, PWelsCabacCtx pBinCtx, uint32_t& uiBinVal) { | ||
| 139 | int32_t iErrorInfo = ERR_NONE; | ||
| 140 | uint32_t uiState = pBinCtx->uiState; | ||
| 141 | uiBinVal = pBinCtx->uiMPS; | ||
| 142 | uint64_t uiOffset = pDecEngine->uiOffset; | ||
| 143 | uint64_t uiRange = pDecEngine->uiRange; | ||
| 144 | |||
| 145 | int32_t iRenorm = 1; | ||
| 146 | uint32_t uiRangeLPS = g_kuiCabacRangeLps[uiState][ (uiRange >> 6) & 0x03]; | ||
| 147 | uiRange -= uiRangeLPS; | ||
| 148 | if (uiOffset >= (uiRange << pDecEngine->iBitsLeft)) { //LPS | ||
| 149 | uiOffset -= (uiRange << pDecEngine->iBitsLeft); | ||
| 150 | uiBinVal ^= 0x0001; | ||
| 151 | if (!uiState) | ||
| 152 | pBinCtx->uiMPS ^= 0x01; | ||
| 153 | pBinCtx->uiState = g_kuiStateTransTable[uiState][0]; | ||
| 154 | iRenorm = g_kRenormTable256[uiRangeLPS]; | ||
| 155 | uiRange = (uiRangeLPS << iRenorm); | ||
| 156 | } else { //MPS | ||
| 157 | pBinCtx->uiState = g_kuiStateTransTable[uiState][1]; | ||
| 158 | if (uiRange >= WELS_CABAC_QUARTER) { | ||
| 159 | pDecEngine->uiRange = uiRange; | ||
| 160 | return ERR_NONE; | ||
| 161 | } else { | ||
| 162 | uiRange <<= 1; | ||
| 163 | } | ||
| 164 | } | ||
| 165 | //Renorm | ||
| 166 | pDecEngine->uiRange = uiRange; | ||
| 167 | pDecEngine->iBitsLeft -= iRenorm; | ||
| 168 | if (pDecEngine->iBitsLeft > 0) { | ||
| 169 | pDecEngine->uiOffset = uiOffset; | ||
| 170 | return ERR_NONE; | ||
| 171 | } | ||
| 172 | uint32_t uiVal = 0; | ||
| 173 | int32_t iNumBitsRead = 0; | ||
| 174 | iErrorInfo = Read32BitsCabac (pDecEngine, uiVal, iNumBitsRead); | ||
| 175 | pDecEngine->uiOffset = (uiOffset << iNumBitsRead) | uiVal; | ||
| 176 | pDecEngine->iBitsLeft += iNumBitsRead; | ||
| 177 | if (iErrorInfo && pDecEngine->iBitsLeft < 0) { | ||
| 178 | return iErrorInfo; | ||
| 179 | } | ||
| 180 | return ERR_NONE; | ||
| 181 | } | ||
| 182 | |||
| 183 | int32_t DecodeBypassCabac (PWelsCabacDecEngine pDecEngine, uint32_t& uiBinVal) { | ||
| 184 | int32_t iErrorInfo = ERR_NONE; | ||
| 185 | int32_t iBitsLeft = pDecEngine->iBitsLeft; | ||
| 186 | uint64_t uiOffset = pDecEngine->uiOffset; | ||
| 187 | uint64_t uiRangeValue; | ||
| 188 | |||
| 189 | |||
| 190 | if (iBitsLeft <= 0) { | ||
| 191 | uint32_t uiVal = 0; | ||
| 192 | int32_t iNumBitsRead = 0; | ||
| 193 | iErrorInfo = Read32BitsCabac (pDecEngine, uiVal, iNumBitsRead); | ||
| 194 | uiOffset = (uiOffset << iNumBitsRead) | uiVal; | ||
| 195 | iBitsLeft = iNumBitsRead; | ||
| 196 | if (iErrorInfo && iBitsLeft == 0) { | ||
| 197 | return iErrorInfo; | ||
| 198 | } | ||
| 199 | } | ||
| 200 | iBitsLeft--; | ||
| 201 | uiRangeValue = (pDecEngine->uiRange << iBitsLeft); | ||
| 202 | if (uiOffset >= uiRangeValue) { | ||
| 203 | pDecEngine->iBitsLeft = iBitsLeft; | ||
| 204 | pDecEngine->uiOffset = uiOffset - uiRangeValue; | ||
| 205 | uiBinVal = 1; | ||
| 206 | return ERR_NONE; | ||
| 207 | } | ||
| 208 | pDecEngine->iBitsLeft = iBitsLeft; | ||
| 209 | pDecEngine->uiOffset = uiOffset; | ||
| 210 | uiBinVal = 0; | ||
| 211 | return ERR_NONE; | ||
| 212 | } | ||
| 213 | |||
| 214 | int32_t DecodeTerminateCabac (PWelsCabacDecEngine pDecEngine, uint32_t& uiBinVal) { | ||
| 215 | int32_t iErrorInfo = ERR_NONE; | ||
| 216 | uint64_t uiRange = pDecEngine->uiRange - 2; | ||
| 217 | int64_t uiOffset = pDecEngine->uiOffset; | ||
| 218 | |||
| 219 | if (uiOffset >= (uiRange << pDecEngine->iBitsLeft)) { | ||
| 220 | uiBinVal = 1; | ||
| 221 | } else { | ||
| 222 | uiBinVal = 0; | ||
| 223 | // Renorm | ||
| 224 | if (uiRange < WELS_CABAC_QUARTER) { | ||
| 225 | int32_t iRenorm = g_kRenormTable256[uiRange]; | ||
| 226 | pDecEngine->uiRange = (uiRange << iRenorm); | ||
| 227 | pDecEngine->iBitsLeft -= iRenorm; | ||
| 228 | if (pDecEngine->iBitsLeft < 0) { | ||
| 229 | uint32_t uiVal = 0; | ||
| 230 | int32_t iNumBitsRead = 0; | ||
| 231 | iErrorInfo = Read32BitsCabac (pDecEngine, uiVal, iNumBitsRead); | ||
| 232 | pDecEngine->uiOffset = (pDecEngine->uiOffset << iNumBitsRead) | uiVal; | ||
| 233 | pDecEngine->iBitsLeft += iNumBitsRead; | ||
| 234 | } | ||
| 235 | if (iErrorInfo && pDecEngine->iBitsLeft < 0) { | ||
| 236 | return iErrorInfo; | ||
| 237 | } | ||
| 238 | return ERR_NONE; | ||
| 239 | } else { | ||
| 240 | pDecEngine->uiRange = uiRange; | ||
| 241 | return ERR_NONE; | ||
| 242 | } | ||
| 243 | } | ||
| 244 | return ERR_NONE; | ||
| 245 | } | ||
| 246 | |||
| 247 | int32_t DecodeUnaryBinCabac (PWelsCabacDecEngine pDecEngine, PWelsCabacCtx pBinCtx, int32_t iCtxOffset, | ||
| 248 | uint32_t& uiSymVal) { | ||
| 249 | uiSymVal = 0; | ||
| 250 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx, uiSymVal)); | ||
| 251 | if (uiSymVal == 0) { | ||
| 252 | return ERR_NONE; | ||
| 253 | } else { | ||
| 254 | uint32_t uiCode; | ||
| 255 | pBinCtx += iCtxOffset; | ||
| 256 | uiSymVal = 0; | ||
| 257 | do { | ||
| 258 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx, uiCode)); | ||
| 259 | ++uiSymVal; | ||
| 260 | } while (uiCode != 0); | ||
| 261 | return ERR_NONE; | ||
| 262 | } | ||
| 263 | } | ||
| 264 | |||
| 265 | int32_t DecodeExpBypassCabac (PWelsCabacDecEngine pDecEngine, int32_t iCount, uint32_t& uiSymVal) { | ||
| 266 | uint32_t uiCode; | ||
| 267 | int32_t iSymTmp = 0; | ||
| 268 | int32_t iSymTmp2 = 0; | ||
| 269 | uiSymVal = 0; | ||
| 270 | do { | ||
| 271 | WELS_READ_VERIFY (DecodeBypassCabac (pDecEngine, uiCode)); | ||
| 272 | if (uiCode == 1) { | ||
| 273 | iSymTmp += (1 << iCount); | ||
| 274 | ++iCount; | ||
| 275 | } | ||
| 276 | } while (uiCode != 0); | ||
| 277 | |||
| 278 | while (iCount--) { | ||
| 279 | WELS_READ_VERIFY (DecodeBypassCabac (pDecEngine, uiCode)); | ||
| 280 | if (uiCode == 1) { | ||
| 281 | iSymTmp2 |= (1 << iCount); | ||
| 282 | } | ||
| 283 | } | ||
| 284 | uiSymVal = (uint32_t) (iSymTmp + iSymTmp2); | ||
| 285 | return ERR_NONE; | ||
| 286 | } | ||
| 287 | |||
| 288 | uint32_t DecodeUEGLevelCabac (PWelsCabacDecEngine pDecEngine, PWelsCabacCtx pBinCtx, uint32_t& uiCode) { | ||
| 289 | uiCode = 0; | ||
| 290 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx, uiCode)); | ||
| 291 | if (uiCode == 0) | ||
| 292 | return ERR_NONE; | ||
| 293 | else { | ||
| 294 | uint32_t uiTmp, uiCount = 1; | ||
| 295 | uiCode = 0; | ||
| 296 | do { | ||
| 297 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx, uiTmp)); | ||
| 298 | ++uiCode; | ||
| 299 | ++uiCount; | ||
| 300 | } while (uiTmp != 0 && uiCount != 13); | ||
| 301 | |||
| 302 | if (uiTmp != 0) { | ||
| 303 | WELS_READ_VERIFY (DecodeExpBypassCabac (pDecEngine, 0, uiTmp)); | ||
| 304 | uiCode += uiTmp + 1; | ||
| 305 | } | ||
| 306 | return ERR_NONE; | ||
| 307 | } | ||
| 308 | return ERR_NONE; | ||
| 309 | } | ||
| 310 | |||
| 311 | int32_t DecodeUEGMvCabac (PWelsCabacDecEngine pDecEngine, PWelsCabacCtx pBinCtx, uint32_t iMaxBin, uint32_t& uiCode) { | ||
| 312 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx + g_kMvdBinPos2Ctx[0], uiCode)); | ||
| 313 | if (uiCode == 0) | ||
| 314 | return ERR_NONE; | ||
| 315 | else { | ||
| 316 | uint32_t uiTmp, uiCount = 1; | ||
| 317 | uiCode = 0; | ||
| 318 | do { | ||
| 319 | WELS_READ_VERIFY (DecodeBinCabac (pDecEngine, pBinCtx + g_kMvdBinPos2Ctx[uiCount++], uiTmp)); | ||
| 320 | uiCode++; | ||
| 321 | } while (uiTmp != 0 && uiCount != 8); | ||
| 322 | |||
| 323 | if (uiTmp != 0) { | ||
| 324 | WELS_READ_VERIFY (DecodeExpBypassCabac (pDecEngine, 3, uiTmp)); | ||
| 325 | uiCode += (uiTmp + 1); | ||
| 326 | } | ||
| 327 | return ERR_NONE; | ||
| 328 | } | ||
| 329 | } | ||
| 330 | } | ||