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ffmpeg / libavfilter / libmpcodecs / vf_perspective.c @ e4852fb3

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1 e4852fb3 Michael Niedermayer
/*
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 * Copyright (C) 2002 Michael Niedermayer <michaelni@gmx.at>
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 *
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 * This file is part of MPlayer.
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 *
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 * MPlayer is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * MPlayer is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License along
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 * with MPlayer; if not, write to the Free Software Foundation, Inc.,
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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <inttypes.h>
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#include <assert.h>
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#include <math.h>
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#include "config.h"
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#include "mp_msg.h"
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#if HAVE_MALLOC_H
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#include <malloc.h>
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#endif
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#include "img_format.h"
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#include "mp_image.h"
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#include "vf.h"
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#define SUB_PIXEL_BITS 8
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#define SUB_PIXELS (1<<SUB_PIXEL_BITS)
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#define COEFF_BITS 11
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//===========================================================================//
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struct vf_priv_s {
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    double ref[4][2];
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    int32_t coeff[1<<SUB_PIXEL_BITS][4];
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    int32_t (*pv)[2];
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    int pvStride;
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    int cubic;
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};
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/***************************************************************************/
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static void initPv(struct vf_priv_s *priv, int W, int H){
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    double a,b,c,d,e,f,g,h,D;
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    double (*ref)[2]= priv->ref;
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    int x,y;
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    g= (  (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])*(ref[2][1] - ref[3][1])
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        - (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])*(ref[2][0] - ref[3][0]))*H;
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    h= (  (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])*(ref[1][0] - ref[3][0])
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        - (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])*(ref[1][1] - ref[3][1]))*W;
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    D=   (ref[1][0] - ref[3][0])*(ref[2][1] - ref[3][1])
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       - (ref[2][0] - ref[3][0])*(ref[1][1] - ref[3][1]);
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    a= D*(ref[1][0] - ref[0][0])*H + g*ref[1][0];
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    b= D*(ref[2][0] - ref[0][0])*W + h*ref[2][0];
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    c= D*ref[0][0]*W*H;
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    d= D*(ref[1][1] - ref[0][1])*H + g*ref[1][1];
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    e= D*(ref[2][1] - ref[0][1])*W + h*ref[2][1];
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    f= D*ref[0][1]*W*H;
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    for(y=0; y<H; y++){
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        for(x=0; x<W; x++){
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            int u, v;
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            u= (int)floor( SUB_PIXELS*(a*x + b*y + c)/(g*x + h*y + D*W*H) + 0.5);
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            v= (int)floor( SUB_PIXELS*(d*x + e*y + f)/(g*x + h*y + D*W*H) + 0.5);
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            priv->pv[x + y*W][0]= u;
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            priv->pv[x + y*W][1]= v;
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        }
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    }
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}
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static double getCoeff(double d){
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    double A= -0.60;
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    double coeff;
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    d= fabs(d);
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    // Equation is from VirtualDub
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    if(d<1.0)
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        coeff = (1.0 - (A+3.0)*d*d + (A+2.0)*d*d*d);
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    else if(d<2.0)
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        coeff = (-4.0*A + 8.0*A*d - 5.0*A*d*d + A*d*d*d);
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    else
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        coeff=0.0;
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    return coeff;
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}
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static int config(struct vf_instance *vf,
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    int width, int height, int d_width, int d_height,
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    unsigned int flags, unsigned int outfmt){
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    int i, j;
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    vf->priv->pvStride= width;
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    vf->priv->pv= (void*)memalign(8, width*height*2*sizeof(int32_t));
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    initPv(vf->priv, width, height);
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    for(i=0; i<SUB_PIXELS; i++){
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        double d= i/(double)SUB_PIXELS;
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        double temp[4];
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        double sum=0;
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        for(j=0; j<4; j++)
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            temp[j]= getCoeff(j - d - 1);
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        for(j=0; j<4; j++)
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            sum+= temp[j];
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        for(j=0; j<4; j++)
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            vf->priv->coeff[i][j]= (int)floor((1<<COEFF_BITS)*temp[j]/sum + 0.5);
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    }
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    return vf_next_config(vf,width,height,d_width,d_height,flags,outfmt);
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}
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static void uninit(struct vf_instance *vf){
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    if(!vf->priv) return;
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    free(vf->priv->pv);
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    vf->priv->pv= NULL;
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    free(vf->priv);
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    vf->priv=NULL;
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}
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static inline void resampleCubic(uint8_t *dst, uint8_t *src, int w, int h, int dstStride, int srcStride, struct vf_priv_s *privParam, int xShift, int yShift){
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    int x, y;
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    struct vf_priv_s priv= *privParam;
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    for(y=0; y<h; y++){
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        for(x=0; x<w; x++){
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            int u, v, subU, subV, sum, sx, sy;
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            sx= x << xShift;
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            sy= y << yShift;
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            u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
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            v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
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            subU= u & (SUB_PIXELS-1);
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            subV= v & (SUB_PIXELS-1);
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            u >>= SUB_PIXEL_BITS;
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            v >>= SUB_PIXEL_BITS;
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            if(u>0 && v>0 && u<w-2 && v<h-2){
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                const int index= u + v*srcStride;
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                const int a= priv.coeff[subU][0];
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                const int b= priv.coeff[subU][1];
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                const int c= priv.coeff[subU][2];
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                const int d= priv.coeff[subU][3];
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                sum=
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                 priv.coeff[subV][0]*(  a*src[index - 1 - srcStride] + b*src[index - 0 - srcStride]
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                                      + c*src[index + 1 - srcStride] + d*src[index + 2 - srcStride])
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                +priv.coeff[subV][1]*(  a*src[index - 1            ] + b*src[index - 0            ]
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                                      + c*src[index + 1            ] + d*src[index + 2            ])
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                +priv.coeff[subV][2]*(  a*src[index - 1 + srcStride] + b*src[index - 0 + srcStride]
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                                      + c*src[index + 1 + srcStride] + d*src[index + 2 + srcStride])
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                +priv.coeff[subV][3]*(  a*src[index - 1+2*srcStride] + b*src[index - 0+2*srcStride]
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                                      + c*src[index + 1+2*srcStride] + d*src[index + 2+2*srcStride]);
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            }else{
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                int dx, dy;
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                sum=0;
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                for(dy=0; dy<4; dy++){
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                    int iy= v + dy - 1;
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                    if     (iy< 0) iy=0;
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                    else if(iy>=h) iy=h-1;
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                    for(dx=0; dx<4; dx++){
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                        int ix= u + dx - 1;
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                        if     (ix< 0) ix=0;
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                        else if(ix>=w) ix=w-1;
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                        sum+=  priv.coeff[subU][dx]*priv.coeff[subV][dy]
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                              *src[ ix + iy*srcStride];
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                    }
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                }
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            }
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            sum= (sum + (1<<(COEFF_BITS*2-1)) ) >> (COEFF_BITS*2);
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            if(sum&~255){
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                if(sum<0) sum=0;
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                else      sum=255;
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            }
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            dst[ x + y*dstStride]= sum;
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        }
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    }
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}
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static inline void resampleLinear(uint8_t *dst, uint8_t *src, int w, int h, int dstStride, int srcStride,
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                  struct vf_priv_s *privParam, int xShift, int yShift){
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    int x, y;
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    struct vf_priv_s priv= *privParam;
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    for(y=0; y<h; y++){
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        for(x=0; x<w; x++){
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            int u, v, subU, subV, sum, sx, sy, index, subUI, subVI;
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            sx= x << xShift;
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            sy= y << yShift;
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            u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
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            v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
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            subU= u & (SUB_PIXELS-1);
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            subV= v & (SUB_PIXELS-1);
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            u >>= SUB_PIXEL_BITS;
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            v >>= SUB_PIXEL_BITS;
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            index= u + v*srcStride;
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            subUI= SUB_PIXELS - subU;
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            subVI= SUB_PIXELS - subV;
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            if((unsigned)u < (unsigned)(w - 1)){
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                if((unsigned)v < (unsigned)(h - 1)){
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                    sum= subVI*(subUI*src[index          ] + subU*src[index          +1])
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                        +subV *(subUI*src[index+srcStride] + subU*src[index+srcStride+1]);
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                    sum= (sum + (1<<(SUB_PIXEL_BITS*2-1)) ) >> (SUB_PIXEL_BITS*2);
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                }else{
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                    if(v<0) v= 0;
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                    else    v= h-1;
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                    index= u + v*srcStride;
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                    sum= subUI*src[index] + subU*src[index+1];
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                    sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
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                }
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            }else{
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                if((unsigned)v < (unsigned)(h - 1)){
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                    if(u<0) u= 0;
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                    else    u= w-1;
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                    index= u + v*srcStride;
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                    sum= subVI*src[index] + subV*src[index+srcStride];
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                    sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
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                }else{
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                    if(u<0) u= 0;
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                    else    u= w-1;
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                    if(v<0) v= 0;
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                    else    v= h-1;
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                    index= u + v*srcStride;
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                    sum= src[index];
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                }
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            }
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            if(sum&~255){
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                if(sum<0) sum=0;
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                else      sum=255;
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            }
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            dst[ x + y*dstStride]= sum;
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        }
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    }
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}
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static int put_image(struct vf_instance *vf, mp_image_t *mpi, double pts){
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    int cw= mpi->w >> mpi->chroma_x_shift;
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    int ch= mpi->h >> mpi->chroma_y_shift;
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    mp_image_t *dmpi=vf_get_image(vf->next,mpi->imgfmt,
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        MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
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        mpi->w,mpi->h);
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    assert(mpi->flags&MP_IMGFLAG_PLANAR);
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    if(vf->priv->cubic){
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        resampleCubic(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
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                vf->priv, 0, 0);
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        resampleCubic(dmpi->planes[1], mpi->planes[1], cw    , ch   , dmpi->stride[1], mpi->stride[1],
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                vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
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        resampleCubic(dmpi->planes[2], mpi->planes[2], cw    , ch   , dmpi->stride[2], mpi->stride[2],
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                vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
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    }else{
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        resampleLinear(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
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                vf->priv, 0, 0);
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        resampleLinear(dmpi->planes[1], mpi->planes[1], cw    , ch   , dmpi->stride[1], mpi->stride[1],
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                vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
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        resampleLinear(dmpi->planes[2], mpi->planes[2], cw    , ch   , dmpi->stride[2], mpi->stride[2],
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                vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
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    }
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    return vf_next_put_image(vf,dmpi, pts);
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}
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//===========================================================================//
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static int query_format(struct vf_instance *vf, unsigned int fmt){
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    switch(fmt)
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    {
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    case IMGFMT_YV12:
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    case IMGFMT_I420:
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    case IMGFMT_IYUV:
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    case IMGFMT_YVU9:
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    case IMGFMT_444P:
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    case IMGFMT_422P:
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    case IMGFMT_411P:
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        return vf_next_query_format(vf, fmt);
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    }
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    return 0;
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}
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static int vf_open(vf_instance_t *vf, char *args){
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    int e;
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    vf->config=config;
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    vf->put_image=put_image;
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//  vf->get_image=get_image;
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    vf->query_format=query_format;
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    vf->uninit=uninit;
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    vf->priv=malloc(sizeof(struct vf_priv_s));
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    memset(vf->priv, 0, sizeof(struct vf_priv_s));
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    if(args==NULL) return 0;
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    e=sscanf(args, "%lf:%lf:%lf:%lf:%lf:%lf:%lf:%lf:%d",
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        &vf->priv->ref[0][0], &vf->priv->ref[0][1],
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        &vf->priv->ref[1][0], &vf->priv->ref[1][1],
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        &vf->priv->ref[2][0], &vf->priv->ref[2][1],
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        &vf->priv->ref[3][0], &vf->priv->ref[3][1],
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        &vf->priv->cubic
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        );
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    if(e!=9)
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        return 0;
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    return 1;
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}
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const vf_info_t vf_info_perspective = {
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    "perspective correcture",
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    "perspective",
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    "Michael Niedermayer",
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    "",
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    vf_open,
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    NULL
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};
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//===========================================================================//