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 * 20 * File Name: omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC.c 21 * OpenMAX DL: v1.0.2 22 * Revision: 9641 23 * Date: Thursday, February 7, 2008 24 * 25 * 26 * 27 * 28 * H.264 decode coefficients module 29 * 30 */ 31 32#include "omxtypes.h" 33#include "armOMX.h" 34#include "omxVC.h" 35 36#include "armCOMM.h" 37#include "armVC.h" 38 39/** 40 * Function: omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC (6.3.4.1.1) 41 * 42 * Description: 43 * Performs CAVLC decoding and inverse raster scan for a 2x2 block of 44 * ChromaDCLevel. The decoded coefficients in the packed position-coefficient 45 * buffer are stored in reverse zig-zag order, i.e., the first buffer element 46 * contains the last non-zero postion-coefficient pair of the block. Within 47 * each position-coefficient pair, the position entry indicates the 48 * raster-scan position of the coefficient, while the coefficient entry 49 * contains the coefficient value. 50 * 51 * Input Arguments: 52 * 53 * ppBitStream - Double pointer to current byte in bit stream buffer 54 * pOffset - Pointer to current bit position in the byte pointed to by 55 * *ppBitStream; valid in the range [0,7]. 56 * 57 * Output Arguments: 58 * 59 * ppBitStream - *ppBitStream is updated after each block is decoded 60 * pOffset - *pOffset is updated after each block is decoded 61 * pNumCoeff - Pointer to the number of nonzero coefficients in this block 62 * ppPosCoefBuf - Double pointer to destination residual 63 * coefficient-position pair buffer. Buffer position 64 * (*ppPosCoefBuf) is updated upon return, unless there are only 65 * zero coefficients in the currently decoded block. In this case 66 * the caller is expected to bypass the transform/dequantization of 67 * the empty blocks. 68 * 69 * Return Value: 70 * 71 * OMX_Sts_NoErr, if the function runs without error. 72 * 73 * OMX_Sts_BadArgErr - bad arguments: if one of the following cases occurs: 74 * - ppBitStream or pOffset is NULL. 75 * - ppPosCoefBuf or pNumCoeff is NULL. 76 * OMX_Sts_Err - if one of the following is true: 77 * - an illegal code is encountered in the bitstream 78 * 79 */ 80 81OMXResult omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC ( 82 const OMX_U8** ppBitStream, 83 OMX_S32* pOffset, 84 OMX_U8* pNumCoeff, 85 OMX_U8** ppPosCoefbuf 86 ) 87 88{ 89 armRetArgErrIf(ppBitStream==NULL , OMX_Sts_BadArgErr); 90 armRetArgErrIf(*ppBitStream==NULL , OMX_Sts_BadArgErr); 91 armRetArgErrIf(pOffset==NULL , OMX_Sts_BadArgErr); 92 armRetArgErrIf(*pOffset<0 , OMX_Sts_BadArgErr); 93 armRetArgErrIf(*pOffset>7 , OMX_Sts_BadArgErr); 94 armRetArgErrIf(pNumCoeff==NULL , OMX_Sts_BadArgErr); 95 armRetArgErrIf(ppPosCoefbuf==NULL , OMX_Sts_BadArgErr); 96 armRetArgErrIf(*ppPosCoefbuf==NULL , OMX_Sts_BadArgErr); 97 98 return armVCM4P10_DecodeCoeffsToPair(ppBitStream, pOffset, pNumCoeff, 99 ppPosCoefbuf, 4, 4); 100 101} 102