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/* ----------------------------------------------------------------
*
*
* File Name: armVCM4P10_DecodeCoeffsToPair.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
*
*/
#ifdef DEBUG_ARMVCM4P10_DECODECOEFFSTOPAIR
#undef DEBUG_ON
#define DEBUG_ON
#endif
#include "omxtypes.h"
#include "armOMX.h"
#include "omxVC.h"
#include "armCOMM.h"
#include "armCOMM_Bitstream.h"
#include "armVCM4P10_CAVLCTables.h"
/* 4x4 DeZigZag table */
static const OMX_U8 armVCM4P10_ZigZag[16] =
{
0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15
};
/*
* Description:
* This function perform the work required by the OpenMAX
* DecodeCoeffsToPair function and DecodeChromaDCCoeffsToPair.
* Since most of the code is common we share it here.
*
* Parameters:
* [in] ppBitStream Double pointer to current byte in bit stream buffer
* [in] pOffset Pointer to current bit position in the byte pointed
* to by *ppBitStream
* [in] sMaxNumCoeff Maximum number of non-zero coefficients in current
* block (4,15 or 16)
* [in] nTable Table number (0 to 4) according to the five columns
* of Table 9-5 in the H.264 spec
* [out] ppBitStream *ppBitStream is updated after each block is decoded
* [out] pOffset *pOffset is updated after each block is decoded
* [out] pNumCoeff Pointer to the number of nonzero coefficients in
* this block
* [out] ppPosCoefbuf Double pointer to destination residual
* coefficient-position pair buffer
* Return Value:
* Standard omxError result. See enumeration for possible result codes.
*/
OMXResult armVCM4P10_DecodeCoeffsToPair(
const OMX_U8** ppBitStream,
OMX_S32* pOffset,
OMX_U8* pNumCoeff,
OMX_U8 **ppPosCoefbuf,
OMX_INT nTable,
OMX_INT sMaxNumCoeff
)
{
int CoeffToken, TotalCoeff, TrailingOnes;
int Level, LevelCode, LevelPrefix, LevelSuffix, LevelSuffixSize;
int SuffixLength, Run, ZerosLeft,CoeffNum;
int i, Flags;
OMX_U8 *pPosCoefbuf = *ppPosCoefbuf;
OMX_S16 pLevel[16];
OMX_U8 pRun[16];
CoeffToken = armUnPackVLC32(ppBitStream, pOffset, armVCM4P10_CAVLCCoeffTokenTables[nTable]);
armRetDataErrIf(CoeffToken == ARM_NO_CODEBOOK_INDEX, OMX_Sts_Err);
TrailingOnes = armVCM4P10_CAVLCTrailingOnes[CoeffToken];
TotalCoeff = armVCM4P10_CAVLCTotalCoeff[CoeffToken];
*pNumCoeff = (OMX_U8)TotalCoeff;
DEBUG_PRINTF_2("TotalCoeff = %d, TrailingOnes = %d\n", TotalCoeff, TrailingOnes);
if (TotalCoeff == 0)
{
/* Nothing to do */
return OMX_Sts_NoErr;
}
/* Decode trailing ones */
for (i=TotalCoeff-1; i>=TotalCoeff-TrailingOnes; i--)
{
if (armGetBits(ppBitStream, pOffset, 1))
{
Level = -1;
}
else
{
Level = +1;
}
pLevel[i] = (OMX_S16)Level;
DEBUG_PRINTF_2("Level[%d] = %d\n", i, pLevel[i]);
}
/* Decode (non zero) level values */
SuffixLength = 0;
if (TotalCoeff>10 && TrailingOnes<3)
{
SuffixLength=1;
}
for ( ; i>=0; i--)
{
LevelPrefix = armUnPackVLC32(ppBitStream, pOffset, armVCM4P10_CAVLCLevelPrefix);
armRetDataErrIf(LevelPrefix == ARM_NO_CODEBOOK_INDEX, OMX_Sts_Err);
LevelSuffixSize = SuffixLength;
if (LevelPrefix==14 && SuffixLength==0)
{
LevelSuffixSize = 4;
}
if (LevelPrefix==15)
{
LevelSuffixSize = 12;
}
LevelSuffix = 0;
if (LevelSuffixSize > 0)
{
LevelSuffix = armGetBits(ppBitStream, pOffset, LevelSuffixSize);
}
LevelCode = (LevelPrefix << SuffixLength) + LevelSuffix;
if (LevelPrefix==15 && SuffixLength==0)
{
LevelCode += 15;
}
/* LevelCode = 2*(magnitude-1) + sign */
if (i==TotalCoeff-1-TrailingOnes && TrailingOnes<3)
{
/* Level magnitude can't be 1 */
LevelCode += 2;
}
if (LevelCode & 1)
{
/* 2a+1 maps to -a-1 */
Level = (-LevelCode-1)>>1;
}
else
{
/* 2a+0 maps to +a+1 */
Level = (LevelCode+2)>>1;
}
pLevel[i] = (OMX_S16)Level;
DEBUG_PRINTF_2("Level[%d] = %d\n", i, pLevel[i]);
if (SuffixLength==0)
{
SuffixLength=1;
}
if ( ((LevelCode>>1)+1)>(3<<(SuffixLength-1)) && SuffixLength<6 )
{
SuffixLength++;
}
}
/* Decode run values */
ZerosLeft = 0;
if (TotalCoeff < sMaxNumCoeff)
{
/* Decode TotalZeros VLC */
if (sMaxNumCoeff==4)
{
ZerosLeft = armUnPackVLC32(ppBitStream, pOffset, armVCM4P10_CAVLCTotalZeros2x2Tables[TotalCoeff-1]);
armRetDataErrIf(ZerosLeft ==ARM_NO_CODEBOOK_INDEX , OMX_Sts_Err);
}
else
{
ZerosLeft = armUnPackVLC32(ppBitStream, pOffset, armVCM4P10_CAVLCTotalZeroTables[TotalCoeff-1]);
armRetDataErrIf(ZerosLeft ==ARM_NO_CODEBOOK_INDEX , OMX_Sts_Err);
}
}
DEBUG_PRINTF_1("TotalZeros = %d\n", ZerosLeft);
CoeffNum=ZerosLeft+TotalCoeff-1;
for (i=TotalCoeff-1; i>0; i--)
{
Run = 0;
if (ZerosLeft > 0)
{
int Table = ZerosLeft;
if (Table > 6)
{
Table = 7;
}
Run = armUnPackVLC32(ppBitStream, pOffset, armVCM4P10_CAVLCRunBeforeTables[Table-1]);
armRetDataErrIf(Run == ARM_NO_CODEBOOK_INDEX, OMX_Sts_Err);
}
pRun[i] = (OMX_U8)Run;
DEBUG_PRINTF_2("Run[%d] = %d\n", i, pRun[i]);
ZerosLeft -= Run;
}
pRun[0] = (OMX_U8)ZerosLeft;
DEBUG_PRINTF_1("Run[0] = %d\n", pRun[i]);
/* Fill in coefficients */
if (sMaxNumCoeff==15)
{
CoeffNum++; /* Skip the DC position */
}
/*for (i=0;i<TotalCoeff;i++)
CoeffNum += pRun[i]+1;*/
for (i=(TotalCoeff-1); i>=0; i--)
{
/*CoeffNum += pRun[i]+1;*/
Level = pLevel[i];
DEBUG_PRINTF_2("Coef[%d] = %d\n", CoeffNum, Level);
Flags = CoeffNum;
CoeffNum -= (pRun[i]+1);
if (sMaxNumCoeff>4)
{
/* Perform 4x4 DeZigZag */
Flags = armVCM4P10_ZigZag[Flags];
}
if (i==0)
{
/* End of block flag */
Flags += 0x20;
}
if (Level<-128 || Level>127)
{
/* Overflow flag */
Flags += 0x10;
}
*pPosCoefbuf++ = (OMX_U8)(Flags);
*pPosCoefbuf++ = (OMX_U8)(Level & 0xFF);
if (Flags & 0x10)
{
*pPosCoefbuf++ = (OMX_U8)(Level>>8);
}
}
*ppPosCoefbuf = pPosCoefbuf;
return OMX_Sts_NoErr;
}
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