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/**
*
* 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 */
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