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/* ----------------------------------------------------------------
*
*
* File Name: omxVCM4P10_DecodeCoeffsToPairCAVLC.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_DecodeCoeffsToPairCAVLC (6.3.4.1.2)
*
* Description:
* Performs CAVLC decoding and inverse zigzag scan for 4x4 block of
* Intra16x16DCLevel, Intra16x16ACLevel, LumaLevel, and ChromaACLevel. Inverse
* field scan is not supported. 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].
* sMaxNumCoeff - Maximum the number of non-zero coefficients in current
* block
* sVLCSelect - VLC table selector, obtained from the number of non-zero
* coefficients contained in the above and left 4x4 blocks. It is
* equivalent to the variable nC described in H.264 standard table
* 9 5, except its value can t be less than zero.
*
* Output Arguments:
*
* ppBitStream - *ppBitStream is updated after each block is decoded.
* 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.
* 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
*
* 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.
* - sMaxNumCoeff is not equal to either 15 or 16.
* - sVLCSelect is less than 0.
*
* OMX_Sts_Err - if one of the following is true:
* - an illegal code is encountered in the bitstream
*
*/
OMXResult omxVCM4P10_DecodeCoeffsToPairCAVLC(
const OMX_U8** ppBitStream,
OMX_S32* pOffset,
OMX_U8* pNumCoeff,
OMX_U8**ppPosCoefbuf,
OMX_INT sVLCSelect,
OMX_INT sMaxNumCoeff
)
{
int nTable;
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);
armRetArgErrIf(sVLCSelect<0 , OMX_Sts_BadArgErr);
armRetArgErrIf(sMaxNumCoeff<15 , OMX_Sts_BadArgErr);
armRetArgErrIf(sMaxNumCoeff>16 , OMX_Sts_BadArgErr);
/* Find VLC table number */
if (sVLCSelect<2)
{
nTable = 0;
}
else if (sVLCSelect<4)
{
nTable = 1;
}
else if (sVLCSelect<8)
{
nTable = 2;
}
else /* sVLCSelect >= 8 */
{
nTable = 3;
}
return armVCM4P10_DecodeCoeffsToPair(ppBitStream, pOffset, pNumCoeff,
ppPosCoefbuf, nTable, sMaxNumCoeff);
}
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