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/*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdint.h>
#include "libavutil/attributes.h"
#include "libavutil/common.h"
#include "config.h"
#include "h263dsp.h"
const uint8_t ff_h263_loop_filter_strength[32]={
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
0, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9,10,10,10,11,11,11,12,12,12
};
static void h263_h_loop_filter_c(uint8_t *src, int stride, int qscale){
int y;
const int strength= ff_h263_loop_filter_strength[qscale];
for(y=0; y<8; y++){
int d1, d2, ad1;
int p0= src[y*stride-2];
int p1= src[y*stride-1];
int p2= src[y*stride+0];
int p3= src[y*stride+1];
int d = (p0 - p3 + 4*(p2 - p1)) / 8;
if (d<-2*strength) d1= 0;
else if(d<- strength) d1=-2*strength - d;
else if(d< strength) d1= d;
else if(d< 2*strength) d1= 2*strength - d;
else d1= 0;
p1 += d1;
p2 -= d1;
if(p1&256) p1= ~(p1>>31);
if(p2&256) p2= ~(p2>>31);
src[y*stride-1] = p1;
src[y*stride+0] = p2;
ad1= FFABS(d1)>>1;
d2= av_clip((p0-p3)/4, -ad1, ad1);
src[y*stride-2] = p0 - d2;
src[y*stride+1] = p3 + d2;
}
}
static void h263_v_loop_filter_c(uint8_t *src, int stride, int qscale){
int x;
const int strength= ff_h263_loop_filter_strength[qscale];
for(x=0; x<8; x++){
int d1, d2, ad1;
int p0= src[x-2*stride];
int p1= src[x-1*stride];
int p2= src[x+0*stride];
int p3= src[x+1*stride];
int d = (p0 - p3 + 4*(p2 - p1)) / 8;
if (d<-2*strength) d1= 0;
else if(d<- strength) d1=-2*strength - d;
else if(d< strength) d1= d;
else if(d< 2*strength) d1= 2*strength - d;
else d1= 0;
p1 += d1;
p2 -= d1;
if(p1&256) p1= ~(p1>>31);
if(p2&256) p2= ~(p2>>31);
src[x-1*stride] = p1;
src[x+0*stride] = p2;
ad1= FFABS(d1)>>1;
d2= av_clip((p0-p3)/4, -ad1, ad1);
src[x-2*stride] = p0 - d2;
src[x+ stride] = p3 + d2;
}
}
av_cold void ff_h263dsp_init(H263DSPContext *ctx)
{
ctx->h263_h_loop_filter = h263_h_loop_filter_c;
ctx->h263_v_loop_filter = h263_v_loop_filter_c;
if (ARCH_X86)
ff_h263dsp_init_x86(ctx);
}
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