| /* |
| * Copyright (C) 2007-2008 ARM Limited |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| /** |
| * |
| * File Name: omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c |
| * OpenMAX DL: v1.0.2 |
| * Revision: 9641 |
| * Date: Thursday, February 7, 2008 |
| * |
| * |
| * |
| * |
| * Description: |
| * Contains modules for zigzag scanning and VLC encoding |
| * for intra block. |
| * |
| */ |
| |
| #include "omxtypes.h" |
| #include "armOMX.h" |
| #include "omxVC.h" |
| |
| #include "armVC.h" |
| #include "armCOMM_Bitstream.h" |
| #include "armCOMM.h" |
| #include "armVCM4P2_Huff_Tables_VLC.h" |
| #include "armVCM4P2_ZigZag_Tables.h" |
| |
| |
| |
| /** |
| * Function: omxVCM4P2_EncodeVLCZigzag_IntraDCVLC (6.2.4.5.2) |
| * |
| * Description: |
| * Performs zigzag scan and VLC encoding of AC and DC coefficients for one |
| * intra block. Two versions of the function (DCVLC and ACVLC) are provided |
| * in order to support the two different methods of processing DC |
| * coefficients, as described in [ISO14496-2], subclause 7.4.1.4, "Intra DC |
| * Coefficient Decoding for the Case of Switched VLC Encoding". |
| * |
| * Input Arguments: |
| * |
| * ppBitStream - double pointer to the current byte in the bitstream |
| * pBitOffset - pointer to the bit position in the byte pointed by |
| * *ppBitStream. Valid within 0 to 7. |
| * pQDctBlkCoef - pointer to the quantized DCT coefficient |
| * predDir - AC prediction direction, which is used to decide the zigzag |
| * scan pattern; takes one of the following values: |
| * - OMX_VC_NONE - AC prediction not used. |
| * Performs classical zigzag scan. |
| * - OMX_VC_HORIZONTAL - Horizontal prediction. |
| * Performs alternate-vertical zigzag scan. |
| * - OMX_VC_VERTICAL - Vertical prediction. |
| * Performs alternate-horizontal zigzag scan. |
| * pattern - block pattern which is used to decide whether this block is |
| * encoded |
| * shortVideoHeader - binary flag indicating presence of |
| * short_video_header; escape modes 0-3 are used if |
| * shortVideoHeader==0, and escape mode 4 is used when |
| * shortVideoHeader==1. |
| * videoComp - video component type (luminance, chrominance) of the current |
| * block |
| * |
| * Output Arguments: |
| * |
| * ppBitStream - *ppBitStream is updated after the block is encoded, so |
| * that it points to the current byte in the bit stream buffer. |
| * pBitOffset - *pBitOffset is updated so that it points to the current bit |
| * position in the byte pointed by *ppBitStream. |
| * |
| * Return Value: |
| * |
| * OMX_Sts_NoErr - no error |
| * OMX_Sts_BadArgErr - Bad arguments: |
| * - At least one of the following pointers is NULL: ppBitStream, |
| * *ppBitStream, pBitOffset, pQDctBlkCoef. |
| * - *pBitOffset < 0, or *pBitOffset >7. |
| * - PredDir is not one of: OMX_VC_NONE, OMX_VC_HORIZONTAL, or |
| * OMX_VC_VERTICAL. |
| * - VideoComp is not one component of enum OMXVCM4P2VideoComponent. |
| * |
| */ |
| |
| OMXResult omxVCM4P2_EncodeVLCZigzag_IntraDCVLC( |
| OMX_U8 **ppBitStream, |
| OMX_INT *pBitOffset, |
| const OMX_S16 *pQDctBlkCoef, |
| OMX_U8 predDir, |
| OMX_U8 pattern, |
| OMX_INT shortVideoHeader, |
| OMXVCM4P2VideoComponent videoComp |
| ) |
| { |
| OMX_S16 dcValue, powOfSize; |
| OMX_U8 DCValueSize, start = 1; |
| OMX_U16 absDCValue; |
| |
| /* Argument error checks */ |
| armRetArgErrIf(ppBitStream == NULL, OMX_Sts_BadArgErr); |
| armRetArgErrIf(*ppBitStream == NULL, OMX_Sts_BadArgErr); |
| armRetArgErrIf(pBitOffset == NULL, OMX_Sts_BadArgErr); |
| armRetArgErrIf(pQDctBlkCoef == NULL, OMX_Sts_BadArgErr); |
| armRetArgErrIf((*pBitOffset < 0) || (*pBitOffset >7), OMX_Sts_BadArgErr); |
| armRetArgErrIf((videoComp != OMX_VC_LUMINANCE) && (videoComp != OMX_VC_CHROMINANCE), OMX_Sts_BadArgErr); |
| armRetArgErrIf((predDir != OMX_VC_NONE) && (predDir != OMX_VC_HORIZONTAL) && (predDir != OMX_VC_VERTICAL) , OMX_Sts_BadArgErr); |
| |
| if (pattern) |
| { |
| dcValue = pQDctBlkCoef[0]; |
| absDCValue = armAbs(dcValue); |
| |
| /* Find the size */ |
| DCValueSize = armLogSize (absDCValue); |
| absDCValue = armAbs(dcValue); |
| |
| /* Insert the code into the bitstream */ |
| if (videoComp == OMX_VC_LUMINANCE) |
| { |
| |
| armPackVLC32 (ppBitStream, pBitOffset, |
| armVCM4P2_aIntraDCLumaIndex[DCValueSize]); |
| } |
| else if (videoComp == OMX_VC_CHROMINANCE) |
| { |
| |
| armPackVLC32 (ppBitStream, pBitOffset, |
| armVCM4P2_aIntraDCChromaIndex[DCValueSize]); |
| } |
| |
| /* Additional code generation in case of negative |
| dc value the additional */ |
| if (DCValueSize > 0) |
| { |
| if (dcValue < 0) |
| { |
| /* calulate 2 pow */ |
| powOfSize = (1 << DCValueSize); |
| |
| absDCValue = absDCValue ^ (powOfSize - 1); |
| } |
| armPackBits(ppBitStream, pBitOffset, (OMX_U32)absDCValue, \ |
| DCValueSize); |
| |
| if (DCValueSize > 8) |
| { |
| armPackBits(ppBitStream, pBitOffset, 1, 1); |
| } |
| } |
| } |
| |
| return armVCM4P2_EncodeVLCZigzag_Intra( |
| ppBitStream, |
| pBitOffset, |
| pQDctBlkCoef, |
| predDir, |
| pattern, |
| shortVideoHeader, |
| start); |
| } |
| |
| /* End of file */ |
