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/* ----------------------------------------------------------------
*
*
* File Name: omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC.c
* OpenMAX DL: v1.0.2
* Revision: 9641
* Date: Thursday, February 7, 2008
*
* (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
*
*
*
* H.264 decode coefficients module
*
*/
#include "omxtypes.h"
#include "armOMX.h"
#include "omxVC.h"
#include "armCOMM.h"
#include "armVC.h"
/**
* Function: omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC (6.3.4.1.1)
*
* Description:
* Performs CAVLC decoding and inverse raster scan for a 2x2 block of
* ChromaDCLevel. The decoded coefficients in the packed position-coefficient
* buffer are stored in reverse zig-zag order, i.e., the first buffer element
* contains the last non-zero postion-coefficient pair of the block. Within
* each position-coefficient pair, the position entry indicates the
* raster-scan position of the coefficient, while the coefficient entry
* contains the coefficient value.
*
* Input Arguments:
*
* ppBitStream - Double pointer to current byte in bit stream buffer
* pOffset - Pointer to current bit position in the byte pointed to by
* *ppBitStream; valid in the range [0,7].
*
* Output Arguments:
*
* ppBitStream - *ppBitStream is updated after each block is decoded
* pOffset - *pOffset is updated after each block is decoded
* pNumCoeff - Pointer to the number of nonzero coefficients in this block
* ppPosCoefBuf - Double pointer to destination residual
* coefficient-position pair buffer. Buffer position
* (*ppPosCoefBuf) is updated upon return, unless there are only
* zero coefficients in the currently decoded block. In this case
* the caller is expected to bypass the transform/dequantization of
* the empty blocks.
*
* Return Value:
*
* OMX_Sts_NoErr, if the function runs without error.
*
* OMX_Sts_BadArgErr - bad arguments: if one of the following cases occurs:
* - ppBitStream or pOffset is NULL.
* - ppPosCoefBuf or pNumCoeff is NULL.
* OMX_Sts_Err - if one of the following is true:
* - an illegal code is encountered in the bitstream
*
*/
OMXResult omxVCM4P10_DecodeChromaDcCoeffsToPairCAVLC (
const OMX_U8** ppBitStream,
OMX_S32* pOffset,
OMX_U8* pNumCoeff,
OMX_U8** ppPosCoefbuf
)
{
armRetArgErrIf(ppBitStream==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*ppBitStream==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(pOffset==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*pOffset<0 , OMX_Sts_BadArgErr);
armRetArgErrIf(*pOffset>7 , OMX_Sts_BadArgErr);
armRetArgErrIf(pNumCoeff==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(ppPosCoefbuf==NULL , OMX_Sts_BadArgErr);
armRetArgErrIf(*ppPosCoefbuf==NULL , OMX_Sts_BadArgErr);
return armVCM4P10_DecodeCoeffsToPair(ppBitStream, pOffset, pNumCoeff,
ppPosCoefbuf, 4, 4);
}
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