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Diffstat (limited to 'media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c')
| -rw-r--r-- | media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c b/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c new file mode 100644 index 0000000..c57acd2 --- /dev/null +++ b/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c @@ -0,0 +1,160 @@ +/** + * + * File Name: omxVCM4P2_EncodeVLCZigzag_IntraDCVLC.c + * OpenMAX DL: v1.0.2 + * Revision: 9641 + * Date: Thursday, February 7, 2008 + * + * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved. + * + * + * + * 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 */ |