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Diffstat (limited to 'media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_DecodeVLCZigzag_IntraACVLC.c')
-rw-r--r-- | media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_DecodeVLCZigzag_IntraACVLC.c | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_DecodeVLCZigzag_IntraACVLC.c b/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_DecodeVLCZigzag_IntraACVLC.c new file mode 100644 index 0000000..96593d1 --- /dev/null +++ b/media/libstagefright/codecs/on2/h264dec/omxdl/reference/vc/m4p2/src/omxVCM4P2_DecodeVLCZigzag_IntraACVLC.c @@ -0,0 +1,103 @@ +/** + * + * File Name: omxVCM4P2_DecodeVLCZigzag_IntraACVLC.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 decoding + * for intra block. + * + */ + +#include "omxtypes.h" +#include "armOMX.h" +#include "omxVC.h" + +#include "armVC.h" +#include "armCOMM.h" + + + +/** + * Function: omxVCM4P2_DecodeVLCZigzag_IntraACVLC (6.2.5.2.2) + * + * Description: + * Performs VLC decoding and inverse zigzag scan 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 - pointer to the pointer to the current byte in the + * bitstream buffer + * pBitOffset - pointer to the bit position in the current byte referenced + * by *ppBitStream. The parameter *pBitOffset is valid in the + * range [0-7]. Bit Position in one byte: |Most Least| *pBitOffset + * |0 1 2 3 4 5 6 7| + * predDir - AC prediction direction; used to select 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. + * 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 or chrominance) of the + * current block + * + * Output Arguments: + * + * ppBitStream - *ppBitStream is updated after the block is decoded such + * that it points to the current byte in the bit stream buffer + * pBitOffset - *pBitOffset is updated such that it points to the current + * bit position in the byte pointed by *ppBitStream + * pDst - pointer to the coefficient buffer of current block; must be + * 4-byte aligned. + * + * Return Value: + * + * OMX_Sts_NoErr - no error + * OMX_Sts_BadArgErr - bad arguments At least one of the following + * pointers is NULL: ppBitStream, *ppBitStream, pBitOffset, pDst, + * or At least one of the following conditions is true: + * *pBitOffset exceeds [0,7], preDir exceeds [0,2], or pDst is + * not 4-byte aligned + * OMX_Sts_Err In DecodeVLCZigzag_IntraDCVLC, dc_size > 12 At least one of + * mark bits equals zero Illegal stream encountered; code cannot + * be located in VLC table Forbidden code encountered in the VLC + * FLC table The number of coefficients is greater than 64 + * + */ + + +OMXResult omxVCM4P2_DecodeVLCZigzag_IntraACVLC( + const OMX_U8 ** ppBitStream, + OMX_INT * pBitOffset, + OMX_S16 * pDst, + OMX_U8 predDir, + OMX_INT shortVideoHeader +) +{ + OMX_U8 start = 0; + + return armVCM4P2_DecodeVLCZigzag_Intra( + ppBitStream, + pBitOffset, + pDst, + predDir, + shortVideoHeader, + start); +} + +/* End of file */ + |