📄 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: inplace filtering and various simplifications (10-Jan-2002)
*
*************************************************************************************
*/
#include <stdlib.h>
#include <string.h>
#include "global.h"
extern const byte QP_SCALE_CR[40] ;
/*********************************************************************************************************/
#define IClip( Min, Max, Val) (((Val)<(Min))? (Min):(((Val)>(Max))? (Max):(Val)))
// 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[40] = {0,0,0,0,0,0,0,0, 4,4,5,6,7,9,10,12, 14,17,20,24,28,33,39,46, 55,65,76,90,106,126,148,175, 207,245,255,255,255,255,255,255} ;
byte BETA_TABLE[40] = {0,0,0,0,0,0,0,0, 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[40][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, 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], struct img_par *img, Macroblock* MbP, Macroblock* MbQ, int dir, int edge, int mb_y, int mb_x ) ;
void EdgeLoop( byte* SrcPtr, byte Strength[4], int QP, int dir, int width, int yuv ) ;
void DeblockMb(ImageParameters *img, byte **imgY, byte ***imgUV, int mb_y, int mb_x) ;
/*!
*****************************************************************************************
* \brief
* The main MB-filtering 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, *SrcV ;
Macroblock *MbP, *MbQ ;
SrcY = imgY [mb_y<<4] + (mb_x<<4) ; // pointers to source
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
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 = max( 0, (MbP->qp + MbQ->qp ) >> 1) ; // Average QP of the two blocks
GetStrength( Strength, img, MbP, MbQ, dir, edge, mb_y<<2, mb_x<<2 ) ; //Strength for 4 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, dir, img->width, 0 ) ;
if( (imgUV != NULL) && !(edge & 1) )
{
EdgeLoop( SrcU + (edge<<1) * ((dir)? img->width_cr:1 ), Strength, QP_SCALE_CR[QP], dir, img->width_cr, 1 ) ;
EdgeLoop( SrcV + (edge<<1) * ((dir)? img->width_cr:1 ), Strength, QP_SCALE_CR[QP], dir, img->width_cr, 1 ) ;
} ;
} ;
} ;
} ;
} ;
}
/*!
*********************************************************************************************
* \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], struct img_par *img, Macroblock* MbP, Macroblock* MbQ, int dir, int edge, int block_y, int block_x )
{
int blkP, blkQ, idx ;
int blk_x, blk_x2, blk_y, blk_y2 ;
*((int*)Strength) = ININT_STRENGTH[edge] ; // Start with Strength=3. or Strength=4 for Mb-edge
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] ;
if( ( img->type != SP_IMG_1) && (img->type != SP_IMG_MULT)
&& !(MbP->b8mode[ BLK_4_TO_8[blkP] ]==IBLOCK || MbP->mb_type==I16MB)
&& !(MbQ->b8mode[ BLK_4_TO_8[blkQ] ]==IBLOCK || 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_1) || (img->type == B_IMG_MULT) )
{
if( (MbQ->mb_type==0) || ((MbQ->mb_type == P8x8) && (MbQ->b8mode[BLK_4_TO_8[blkQ]]==0)) )
Strength[idx] = (abs( img->dfMV [blk_x][blk_y][0] - img->dfMV [blk_x2][blk_y2][0]) >= 4) |
(abs( img->dfMV [blk_x][blk_y][1] - img->dfMV [blk_x2][blk_y2][1]) >= 4) |
(abs( img->dbMV [blk_x][blk_y][0] - img->dbMV [blk_x2][blk_y2][0]) >= 4) |
(abs( img->dbMV [blk_x][blk_y][1] - img->dbMV [blk_x2][blk_y2][1]) >= 4) ;
else
Strength[idx] = (abs( img->fw_mv[blk_x][blk_y][0] - img->fw_mv[blk_x2][blk_y2][0]) >= 4) |
(abs( img->fw_mv[blk_x][blk_y][1] - img->fw_mv[blk_x2][blk_y2][1]) >= 4) |
(abs( img->bw_mv[blk_x][blk_y][0] - img->bw_mv[blk_x2][blk_y2][0]) >= 4) |
(abs( img->bw_mv[blk_x][blk_y][1] - img->bw_mv[blk_x2][blk_y2][1]) >= 4) ;
}
else
Strength[idx] = (abs( img->mv[blk_x][blk_y][0] - img->mv[blk_x2][blk_y2][0]) >= 4 ) |
(abs( img->mv[blk_x][blk_y][1] - img->mv[blk_x2][blk_y2][1]) >= 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 dir, int width, int yuv )
{
int Alpha, Beta ;
int pel, ap, aq, PtrInc, Strng ;
int inc, inc2, inc3, inc4 ;
int C0, c0, Delta, dif, AbsDelta ;
int L2, L1, L0, R0, R1, R2, RL0 ;
byte* ClipTab ;
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 ;
Alpha = ALPHA_TABLE[ QP ] ;
Beta = BETA_TABLE [ QP ] ;
ClipTab = CLIP_TAB [ QP ] ;
for( pel=0 ; pel<16 ; pel++ )
{
if( Strng = Strength[pel >> 2] )
{
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 )
{
L2 = SrcPtr[-inc3] ;
R2 = SrcPtr[ inc2] ;
aq = (abs( R0 - R2) - Beta ) < 0 ;
ap = (abs( L0 - L2) - Beta ) < 0 ;
if( (Strng == 4) && (ap+aq == 2) && (AbsDelta >= 2) && (AbsDelta < (QP>>2)) ) // INTRA strong filtering
{
RL0 = L0 + R0 ;
SrcPtr[ 0 ] = ( L1 + ((R1 + RL0) << 1) + SrcPtr[ inc2] + 4) >> 3 ;
SrcPtr[-inc ] = ( R1 + ((L1 + RL0) << 1) + SrcPtr[-inc3] + 4) >> 3 ;
SrcPtr[ inc ] = ( SrcPtr[ inc3] + ((SrcPtr[ inc2] + R0 + R1) << 1) + L0 + 4) >> 3 ;
SrcPtr[-inc2] = ( SrcPtr[-inc4] + ((SrcPtr[-inc3] + L1 + L0) << 1) + R0 + 4) >> 3 ;
if( !yuv )
{
SrcPtr[-inc3] = (((SrcPtr[-inc4] + SrcPtr[-inc3]) <<1) + SrcPtr[-inc3] + L1 + RL0 + 4) >> 3 ;
SrcPtr[ inc2] = (((SrcPtr[ inc3] + SrcPtr[ inc2]) <<1) + SrcPtr[ inc2] + R1 + RL0 + 4) >> 3 ;
}
}
else // normal filtering
{
c0 = 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( !yuv )
{
if( ap )
SrcPtr[-inc2] += IClip( -C0, C0, ( L2 + SrcPtr[-inc] - (L1<<1)) >> 1 ) ;
if( aq )
SrcPtr[ inc] += IClip( -C0, C0, ( R2 + SrcPtr[ 0] - (R1<<1)) >> 1 ) ;
} ;
} ;
} ;
} ;
SrcPtr += PtrInc ; // Increment to next set of pixel
pel += yuv ;
}
else
{
SrcPtr += PtrInc << (2 - yuv) ;
pel += 3 ;
} ;
}
}
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