📄 loopfilter.c
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/*
***********************************************************************
* COPYRIGHT AND WARRANTY INFORMATION
*
* Copyright 2001, International Telecommunications Union, Geneva
*
* DISCLAIMER OF WARRANTY
*
* These software programs are available to the user without any
* license fee or royalty on an "as is" basis. The ITU disclaims
* any and all warranties, whether express, implied, or
* statutory, including any implied warranties of merchantability
* or of fitness for a particular purpose. In no event shall the
* contributor or the ITU be liable for any incidental, punitive, or
* consequential damages of any kind whatsoever arising from the
* use of these programs.
*
* This disclaimer of warranty extends to the user of these programs
* and user's customers, employees, agents, transferees, successors,
* and assigns.
*
* The ITU does not represent or warrant that the programs furnished
* hereunder are free of infringement of any third-party patents.
* Commercial implementations of ITU-T Recommendations, including
* shareware, may be subject to royalty fees to patent holders.
* Information regarding the ITU-T patent policy is available from
* the ITU Web site at http://www.itu.int.
*
* THIS IS NOT A GRANT OF PATENT RIGHTS - SEE THE ITU-T PATENT POLICY.
************************************************************************
*/
/*!
*************************************************************************************
* \file loopFilter.c
*
* \brief
* Filter to reduce blocking artifacts on a macroblock level.
* The filter strengh is QP dependent.
*
* \author
* Contributors:
* - Peter List Peter.List@t-systems.de: Original code (13-Aug-2001)
* - Jani Lainema Jani.Lainema@nokia.com: Some bug fixing, removal of recusiveness (16-Aug-2001)
* - Peter List Peter.List@t-systems.de: Recusiveness back and various simplifications (10-Jan-2002)
* - Peter List Peter.List@t-systems.de: New structure, lot's of simplifications. Adopted
* thresholds for extended QPs. No more recusiveness
* for strog filtering, (12-Mar-2002)
* - Anthony Joch anthony@ubvideo.com: Simplified switching between filters and non-recursive
* default filter (mods 1 & 3 from JVT-C094). (08-Jul-2002)
* - Cristina Gomila cristina.gomila@thomson.net: Simplification of the chroma deblocking from JVT-E089 (21-Nov-2002)
*
*************************************************************************************
*/
#include <stdlib.h>
#include <string.h>
#include "global.h"
#define IClip( Min, Max, Val) (((Val)<(Min))? (Min):(((Val)>(Max))? (Max):(Val)))
extern const byte QP_SCALE_CR[52] ;
/*************************************************************************************/
// NOTE: to change the tables below for instance when the QP doubling is changed from 6 to 8 values
// send an e-mail to Peter.List@t-systems.com to get a little programm that calculates them automatically
byte ALPHA_TABLE[52] = {0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,4,4,5,6, 7,8,9,10,12,13,15,17, 20,22,25,28,32,36,40,45, 50,56,63,71,80,90,101,113, 127,144,162,182,203,226,255,255} ;
byte BETA_TABLE[52] = {0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,2,2,2,3, 3,3,3, 4, 4, 4, 6, 6, 7, 7, 8, 8, 9, 9,10,10, 11,11,12,12,13,13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18} ;
byte CLIP_TAB[52][5] =
{
{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},
{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},{ 0, 0, 0, 0, 0},
{ 0, 0, 0, 0, 0},{ 0, 0, 0, 1, 1},{ 0, 0, 0, 1, 1},{ 0, 0, 0, 1, 1},{ 0, 0, 0, 1, 1},{ 0, 0, 1, 1, 1},{ 0, 0, 1, 1, 1},{ 0, 1, 1, 1, 1},
{ 0, 1, 1, 1, 1},{ 0, 1, 1, 1, 1},{ 0, 1, 1, 1, 1},{ 0, 1, 1, 2, 2},{ 0, 1, 1, 2, 2},{ 0, 1, 1, 2, 2},{ 0, 1, 1, 2, 2},{ 0, 1, 2, 3, 3},
{ 0, 1, 2, 3, 3},{ 0, 2, 2, 3, 3},{ 0, 2, 2, 4, 4},{ 0, 2, 3, 4, 4},{ 0, 2, 3, 4, 4},{ 0, 3, 3, 5, 5},{ 0, 3, 4, 6, 6},{ 0, 3, 4, 6, 6},
{ 0, 4, 5, 7, 7},{ 0, 4, 5, 8, 8},{ 0, 4, 6, 9, 9},{ 0, 5, 7,10,10},{ 0, 6, 8,11,11},{ 0, 6, 8,13,13},{ 0, 7,10,14,14},{ 0, 8,11,16,16},
{ 0, 9,12,18,18},{ 0,10,13,20,20},{ 0,11,15,23,23},{ 0,13,17,25,25}
} ;
void GetStrength(byte Strength[4],Macroblock* MbP,Macroblock* MbQ,int dir,int edge,int block_y,int block_x);
void EdgeLoop(byte* SrcPtr,byte Strength[4],int QP, int AlphaC0Offset, int BetaOffset, int dir,int width,int Chro);
void DeblockMb(ImageParameters *img, byte **imgY, byte ***imgUV, int blk_y, int blk_x) ;
/*!
*****************************************************************************************
* \brief
* The main Deblocking function
*****************************************************************************************
*/
void DeblockFrame(ImageParameters *img, byte **imgY, byte ***imgUV)
{
int mb_x, mb_y ;
for( mb_y=0 ; mb_y<(img->height>>4) ; mb_y++ )
for( mb_x=0 ; mb_x<(img->width>>4) ; mb_x++ )
DeblockMb( img, imgY, imgUV, mb_y, mb_x ) ;
}
/*!
*****************************************************************************************
* \brief
* Deblocks one macroblock
*****************************************************************************************
*/
void DeblockMb(ImageParameters *img, byte **imgY, byte ***imgUV, int mb_y, int mb_x)
{
int EdgeCondition;
int dir, edge, QP ;
byte Strength[4], *SrcY, *SrcU = NULL, *SrcV = NULL;
Macroblock *MbP, *MbQ ;
int QPC;
SrcY = imgY [mb_y<<4] + (mb_x<<4) ; // pointers to source
if (imgUV != NULL)
{
SrcU = imgUV[0][mb_y<<3] + (mb_x<<3) ;
SrcV = imgUV[1][mb_y<<3] + (mb_x<<3) ;
}
MbQ = &img->mb_data[mb_y*(img->width>>4) + mb_x] ; // current Mb
// This could also be handled as a filter offset of -51
if (MbQ->lf_disable) return;
for( dir=0 ; dir<2 ; dir++ ) // vertical edges, than horicontal edges
{
EdgeCondition = (dir && mb_y) || (!dir && mb_x) ; // can not filter beyond frame boundaries
for( edge=0 ; edge<4 ; edge++ ) // first 4 vertical strips of 16 pel
{ // then 4 horicontal
if( edge || EdgeCondition )
{
MbP = (edge)? MbQ : ((dir)? (MbQ -(img->width>>4)) : (MbQ-1) ) ; // MbP = Mb of the remote 4x4 block
QP = (MbP->qp + MbQ->qp + 1) >> 1 ; // Average QP of the two blocks
GetStrength( Strength, MbP, MbQ, dir, edge, mb_y<<2, mb_x<<2); //Strength for 4 pairs of blks in 1 stripe
if( *((int*)Strength) ) // && (QP>= 8) ) // only if one of the 4 Strength bytes is != 0
{
EdgeLoop( SrcY + (edge<<2)* ((dir)? img->width:1 ), Strength, QP, MbQ->lf_alpha_c0_offset, MbQ->lf_beta_offset, dir, img->width, 0 );
if( (imgUV != NULL) && !(edge & 1) )
{
QPC = (QP_SCALE_CR[MbP->qp] + QP_SCALE_CR[MbQ->qp] + 1) >> 1;
EdgeLoop( SrcU + (edge<<1) * ((dir)? img->width_cr:1 ), Strength, QPC, MbQ->lf_alpha_c0_offset, MbQ->lf_beta_offset, dir, img->width_cr, 1 ) ;
EdgeLoop( SrcV + (edge<<1) * ((dir)? img->width_cr:1 ), Strength, QPC, MbQ->lf_alpha_c0_offset, MbQ->lf_beta_offset, dir, img->width_cr, 1 ) ;
}
}
}
}//end edge
}//end loop dir
}
/*!
*********************************************************************************************
* \brief
* returns a buffer of 4 Strength values for one stripe in a mb (for different Frame types)
*********************************************************************************************
*/
int ININT_STRENGTH[4] = {0x04040404, 0x03030303, 0x03030303, 0x03030303} ;
byte BLK_NUM[2][4][4] = {{{0,4,8,12},{1,5,9,13},{2,6,10,14},{3,7,11,15}},{{0,1,2,3},{4,5,6,7},{8,9,10,11},{12,13,14,15}}} ;
byte BLK_4_TO_8[16] = {0,0,1,1,0,0,1,1,2,2,3,3,2,2,3,3} ;
void GetStrength(byte Strength[4],Macroblock* MbP,Macroblock* MbQ,int dir,int edge,int block_y,int block_x)
{
int blkP, blkQ, idx ;
int blk_x2, blk_y2, blk_x, blk_y ;
if (img->field_picture == 0)
*((int*)Strength) = ININT_STRENGTH[edge] ; // Assume INTRA -> Strength=3. (or Strength=4 for Mb-edge)
else
*((int*)Strength) = ININT_STRENGTH[3] ; // Assume INTRA -> Strength=3. (for fields)
for( idx=0 ; idx<4 ; idx++ )
{ // if not intra or SP-frame
blkQ = BLK_NUM[dir][ edge ][idx] ; // if one of the 4x4 blocks has coefs. set Strength=2
blkP = BLK_NUM[dir][(edge-1) & 3][idx] ;
blk_y = block_y + (blkQ >> 2) ;
blk_x = block_x + (blkQ & 3)+4 ;
if( !(MbP->mb_type==I4MB || MbP->mb_type==I16MB) && (img->types != SP_IMG)
&& !(MbQ->mb_type==I4MB || MbQ->mb_type==I16MB) )
{
if( ((MbQ->cbp_blk & (1 << blkQ )) != 0) || ((MbP->cbp_blk & (1 << blkP)) != 0) )
Strength[idx] = 2 ;
else
{ // if no coefs, but vector difference >= 1 set Strength=1
blk_y = block_y + (blkQ >> 2) ; blk_y2 = blk_y - dir ;
blk_x = block_x + (blkQ & 3)+4 ; blk_x2 = blk_x - !dir ;
if( img->type == B_IMG || img->type == BS_IMG )
{
Strength[idx] = (abs( tmp_fwMV[0][blk_y][blk_x] - tmp_fwMV[0][blk_y2][blk_x2]) >= 4) |
(abs( tmp_fwMV[1][blk_y][blk_x] - tmp_fwMV[1][blk_y2][blk_x2]) >= 4) |
(abs( tmp_bwMV[0][blk_y][blk_x] - tmp_bwMV[0][blk_y2][blk_x2]) >= 4) |
(abs( tmp_bwMV[1][blk_y][blk_x] - tmp_bwMV[1][blk_y2][blk_x2]) >= 4) |
(fw_refFrArr [blk_y][blk_x-4] != fw_refFrArr[blk_y2][blk_x2-4]) |
(bw_refFrArr [blk_y][blk_x-4] != bw_refFrArr[blk_y2][blk_x2-4]);
}
else
Strength[idx] = (abs( tmp_mv[0][blk_y][blk_x] - tmp_mv[0][blk_y2][blk_x2]) >= 4 ) |
(abs( tmp_mv[1][blk_y][blk_x] - tmp_mv[1][blk_y2][blk_x2]) >= 4) |
( refFrArr [blk_y][blk_x-4] != refFrArr[blk_y2][blk_x2-4]);
}
}
}
}
/*!
*****************************************************************************************
* \brief
* Filters one edge of 16 (luma) or 8 (chroma) pel
*****************************************************************************************
*/
void EdgeLoop(byte* SrcPtr,byte Strength[4],int QP,
int AlphaC0Offset, int BetaOffset, int dir,int width,int Chro)
{
int pel, ap = 0, aq = 0, PtrInc, Strng ;
int inc, inc2, inc3, inc4 ;
int C0, c0, Delta, dif, AbsDelta ;
int L2 = 0, L1, L0, R0, R1, R2 = 0, RL0 ;
int Alpha = 0, Beta =0 ;
byte* ClipTab = NULL;
int small_gap;
int indexA, indexB;
PtrInc = dir? 1 : width ;
inc = dir? width : 1 ; // vertical filtering increment to next pixel is 1 else width
inc2 = inc<<1 ;
inc3 = inc + inc2 ;
inc4 = inc<<2 ;
for( pel=0 ; pel<16 ; pel++ )
{
if(!(pel&3))
{
indexA = IClip(0, MAX_QP, QP + AlphaC0Offset);
indexB = IClip(0, MAX_QP, QP + BetaOffset);
Alpha=ALPHA_TABLE[indexA];
Beta=BETA_TABLE[indexB];
ClipTab=CLIP_TAB[indexA];
}
if( (Strng = Strength[pel >> 2]) ) // double braces to avoid gcc warnings
{
L0 = SrcPtr [-inc ] ;
R0 = SrcPtr [ 0] ;
AbsDelta = abs( Delta = R0 - L0 ) ;
if( AbsDelta < Alpha )
{
C0 = ClipTab[ Strng ] ;
L1 = SrcPtr[-inc2] ;
R1 = SrcPtr[ inc ] ;
if( ((abs(R0 - R1) - Beta) & (abs(L0 - L1) - Beta) ) < 0 )
{
if( !Chro)
{
L2 = SrcPtr[-inc3] ;
R2 = SrcPtr[ inc2] ;
aq = (abs( R0 - R2) - Beta ) < 0 ;
ap = (abs( L0 - L2) - Beta ) < 0 ;
}
RL0 = L0 + R0 ;
if(Strng == 4 ) // INTRA strong filtering
{
if( Chro) // Chroma
{
SrcPtr[ 0 ] = ((R1 << 1) + R0 + L1 + 2) >> 2;
SrcPtr[-inc ] = ((L1 << 1) + L0 + R1 + 2) >> 2;
}
else // Luma
{
small_gap = (AbsDelta < ((Alpha >> 2) + 2));
aq &= small_gap;
ap &= small_gap;
SrcPtr[ 0 ] = aq ? ( L1 + ((R1 + RL0) << 1) + SrcPtr[ inc2] + 4) >> 3 : ((R1 << 1) + R0 + L1 + 2) >> 2 ;
SrcPtr[-inc ] = ap ? ( R1 + ((L1 + RL0) << 1) + SrcPtr[-inc3] + 4) >> 3 : ((L1 << 1) + L0 + R1 + 2) >> 2 ;
SrcPtr[ inc ] = aq ? ( SrcPtr[ inc2] + R0 + R1 + L0 + 2) >> 2 : SrcPtr[ inc ];
SrcPtr[-inc2] = ap ? ( SrcPtr[-inc3] + L1 + L0 + R0 + 2) >> 2 : SrcPtr[-inc2];
SrcPtr[ inc2] = aq ? (((SrcPtr[ inc3] + SrcPtr[ inc2]) <<1) + SrcPtr[ inc2] + R1 + RL0 + 4) >> 3 : R2;
SrcPtr[-inc3] = ap ? (((SrcPtr[-inc4] + SrcPtr[-inc3]) <<1) + SrcPtr[-inc3] + L1 + RL0 + 4) >> 3 : L2;
}
}
else // normal filtering
{
c0 = Chro? (C0+1):(C0 + ap + aq) ;
dif = IClip( -c0, c0, ( (Delta << 2) + (L1 - R1) + 4) >> 3 ) ;
SrcPtr[ -inc ] = IClip(0, 255, L0 + dif) ;
SrcPtr[ 0 ] = IClip(0, 255, R0 - dif) ;
if( !Chro )
{
if( ap )
SrcPtr[-inc2] += IClip( -C0, C0, ( L2 + ((RL0+1) >> 1) - (L1<<1)) >> 1 ) ;
if( aq )
SrcPtr[ inc] += IClip( -C0, C0, ( R2 + ((RL0+1) >> 1) - (R1<<1)) >> 1 ) ;
} ;
} ;
} ;
} ;
SrcPtr += PtrInc ; // Increment to next set of pixel
pel += Chro ;
}
else
{
SrcPtr += PtrInc << (2 - Chro) ;
pel += 3 ;
} ;
}
}
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