1 /** 2 * 3 * File Name: omxVCM4P2_DecodeBlockCoef_Intra.c 4 * OpenMAX DL: v1.0.2 5 * Revision: 12290 6 * Date: Wednesday, April 9, 2008 7 * 8 * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved. 9 * 10 * 11 * 12 * Description: 13 * Contains modules for intra reconstruction 14 * 15 */ 16 17 #include "omxtypes.h" 18 #include "armOMX.h" 19 #include "omxVC.h" 20 21 #include "armCOMM.h" 22 #include "armVC.h" 23 24 /* Function for saturating 16 bit values to the [0,255] range and */ 25 /* writing out as 8 bit values. Does 64 entries */ 26 void armVCM4P2_Clip8(OMX_S16 *pSrc, OMX_U8 *pDst, OMX_INT dstStep ); 27 28 29 30 /** 31 * Function: omxVCM4P2_DecodeBlockCoef_Intra 32 * 33 * Description: 34 * Decodes the INTRA block coefficients. Inverse quantization, inversely zigzag 35 * positioning, and IDCT, with appropriate clipping on each step, are performed 36 * on the coefficients. The results are then placed in the output frame/plane on 37 * a pixel basis. For INTRA block, the output values are clipped to [0, 255] and 38 * written to corresponding block buffer within the destination plane. 39 * 40 * Remarks: 41 * 42 * Parameters: 43 * [in] ppBitStream pointer to the pointer to the current byte in 44 * the bit stream buffer. There is no boundary 45 * check for the bit stream buffer. 46 * [in] pBitOffset pointer to the bit position in the byte pointed 47 * to by *ppBitStream. *pBitOffset is valid within 48 * [0-7]. 49 * [in] step width of the destination plane 50 * [in/out] pCoefBufRow [in] pointer to the coefficient row buffer 51 * [out] updated coefficient rwo buffer 52 * [in/out] pCoefBufCol [in] pointer to the coefficient column buffer 53 * [out] updated coefficient column buffer 54 * [in] curQP quantization parameter of the macroblock which 55 * the current block belongs to 56 * [in] pQpBuf Pointer to a 2-element QP array. pQpBuf[0] holds the QP of the 8x8 block left to 57 * the current block(QPa). pQpBuf[1] holds the QP of the 8x8 block just above the 58 * current block(QPc). 59 * Note, in case the corresponding block is out of VOP bound, the QP value will have 60 * no effect to the intra-prediction process. Refer to subclause "7.4.3.3 Adaptive 61 * ac coefficient prediction" of ISO/IEC 14496-2(MPEG4 Part2) for accurate description. 62 * [in] blockIndex block index indicating the component type and 63 * position as defined in subclause 6.1.3.8, 64 * Figure 6-5 of ISO/IEC 14496-2. 65 * [in] intraDCVLC a code determined by intra_dc_vlc_thr and QP. 66 * This allows a mechanism to switch between two VLC 67 * for coding of Intra DC coefficients as per Table 68 * 6-21 of ISO/IEC 14496-2. 69 * [in] ACPredFlag a flag equal to ac_pred_flag (of luminance) indicating 70 * if the ac coefficients of the first row or first 71 * column are differentially coded for intra coded 72 * macroblock. 73 * [in] shortVideoHeader a flag indicating presence of short_video_header; 74 * shortVideoHeader==1 selects linear intra DC mode, 75 * and shortVideoHeader==0 selects nonlinear intra DC mode. 76 * [out] ppBitStream *ppBitStream is updated after the block is 77 * decoded, so that it points to the current byte 78 * in the bit stream buffer 79 * [out] pBitOffset *pBitOffset is updated so that it points to the 80 * current bit position in the byte pointed by 81 * *ppBitStream 82 * [out] pDst pointer to the block in the destination plane. 83 * pDst should be 16-byte aligned. 84 * [out] pCoefBufRow pointer to the updated coefficient row buffer. 85 * 86 * Return Value: 87 * OMX_Sts_NoErr - no error 88 * OMX_Sts_BadArgErr - bad arguments 89 * - At least one of the following pointers is NULL: ppBitStream, *ppBitStream, pBitOffset, 90 * pCoefBufRow, pCoefBufCol, pQPBuf, pDst. 91 * or 92 * - At least one of the below case: *pBitOffset exceeds [0,7], curQP exceeds (1, 31), 93 * blockIndex exceeds [0,9], step is not the multiple of 8, intraDCVLC is zero while 94 * blockIndex greater than 5. 95 * or 96 * - pDst is not 16-byte aligned 97 * OMX_Sts_Err - status error 98 * 99 */ 100 101 OMXResult omxVCM4P2_DecodeBlockCoef_Intra( 102 const OMX_U8 ** ppBitStream, 103 OMX_INT *pBitOffset, 104 OMX_U8 *pDst, 105 OMX_INT step, 106 OMX_S16 *pCoefBufRow, 107 OMX_S16 *pCoefBufCol, 108 OMX_U8 curQP, 109 const OMX_U8 *pQPBuf, 110 OMX_INT blockIndex, 111 OMX_INT intraDCVLC, 112 OMX_INT ACPredFlag, 113 OMX_INT shortVideoHeader 114 ) 115 { 116 OMX_S16 tempBuf1[79], tempBuf2[79]; 117 OMX_S16 *pTempBuf1, *pTempBuf2; 118 OMX_INT predDir, predACDir; 119 OMX_INT predQP; 120 OMXVCM4P2VideoComponent videoComp; 121 OMXResult errorCode; 122 123 124 /* Aligning the local buffers */ 125 pTempBuf1 = armAlignTo16Bytes(tempBuf1); 126 pTempBuf2 = armAlignTo16Bytes(tempBuf2); 127 128 /* Setting the AC prediction direction and prediction direction */ 129 armVCM4P2_SetPredDir( 130 blockIndex, 131 pCoefBufRow, 132 pCoefBufCol, 133 &predDir, 134 &predQP, 135 pQPBuf); 136 137 predACDir = predDir; 138 139 140 if (ACPredFlag == 0) 141 { 142 predACDir = OMX_VC_NONE; 143 } 144 145 /* Setting the videoComp */ 146 if (blockIndex <= 3) 147 { 148 videoComp = OMX_VC_LUMINANCE; 149 } 150 else 151 { 152 videoComp = OMX_VC_CHROMINANCE; 153 } 154 155 156 /* VLD and zigzag */ 157 if (intraDCVLC == 1) 158 { 159 errorCode = omxVCM4P2_DecodeVLCZigzag_IntraDCVLC( 160 ppBitStream, 161 pBitOffset, 162 pTempBuf1, 163 predACDir, 164 shortVideoHeader, 165 videoComp); 166 armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode); 167 } 168 else 169 { 170 errorCode = omxVCM4P2_DecodeVLCZigzag_IntraACVLC( 171 ppBitStream, 172 pBitOffset, 173 pTempBuf1, 174 predACDir, 175 shortVideoHeader); 176 armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode); 177 } 178 179 /* AC DC prediction */ 180 errorCode = omxVCM4P2_PredictReconCoefIntra( 181 pTempBuf1, 182 pCoefBufRow, 183 pCoefBufCol, 184 curQP, 185 predQP, 186 predDir, 187 ACPredFlag, 188 videoComp); 189 armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode); 190 191 /* Dequantization */ 192 errorCode = omxVCM4P2_QuantInvIntra_I( 193 pTempBuf1, 194 curQP, 195 videoComp, 196 shortVideoHeader); 197 armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode); 198 199 /* Inverse transform */ 200 errorCode = omxVCM4P2_IDCT8x8blk (pTempBuf1, pTempBuf2); 201 armRetDataErrIf((errorCode != OMX_Sts_NoErr), errorCode); 202 203 /* Placing the linear array into the destination plane and clipping 204 it to 0 to 255 */ 205 206 armVCM4P2_Clip8(pTempBuf2,pDst,step); 207 208 209 return OMX_Sts_NoErr; 210 } 211 212 /* End of file */ 213 214 215
