libavfilter/libmpcodecs/vf_perspective.c - third_party/ffmpeg - Git at Google

 /*
  * Copyright (C) 2002 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of MPlayer.
  *
  * MPlayer is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * MPlayer 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 General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License along
  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <inttypes.h>
 #include <assert.h>
 #include <math.h>

 #include "config.h"
 #include "mp_msg.h"

 #if HAVE_MALLOC_H
 #include <malloc.h>
 #endif

 #include "libavutil/mem.h"

 #include "img_format.h"
 #include "mp_image.h"
 #include "vf.h"

 #define SUB_PIXEL_BITS 8
 #define SUB_PIXELS (1<<SUB_PIXEL_BITS)
 #define COEFF_BITS 11

 //===========================================================================//

 struct vf_priv_s {
     double ref[4][2];
     int32_t coeff[1<<SUB_PIXEL_BITS][4];
     int32_t (*pv)[2];
     int pvStride;
     int cubic;
 };


 /***************************************************************************/

 static void initPv(struct vf_priv_s *priv, int W, int H){
     double a,b,c,d,e,f,g,h,D;
     double (*ref)[2]= priv->ref;
     int x,y;

     g= (  (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])*(ref[2][1] - ref[3][1])
         - (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])*(ref[2][0] - ref[3][0]))*H;
     h= (  (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])*(ref[1][0] - ref[3][0])
         - (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])*(ref[1][1] - ref[3][1]))*W;
     D=   (ref[1][0] - ref[3][0])*(ref[2][1] - ref[3][1])
        - (ref[2][0] - ref[3][0])*(ref[1][1] - ref[3][1]);

     a= D*(ref[1][0] - ref[0][0])*H + g*ref[1][0];
     b= D*(ref[2][0] - ref[0][0])*W + h*ref[2][0];
     c= D*ref[0][0]*W*H;
     d= D*(ref[1][1] - ref[0][1])*H + g*ref[1][1];
     e= D*(ref[2][1] - ref[0][1])*W + h*ref[2][1];
     f= D*ref[0][1]*W*H;

     for(y=0; y<H; y++){
         for(x=0; x<W; x++){
             int u, v;

             u= (int)floor( SUB_PIXELS*(a*x + b*y + c)/(g*x + h*y + D*W*H) + 0.5);
             v= (int)floor( SUB_PIXELS*(d*x + e*y + f)/(g*x + h*y + D*W*H) + 0.5);

             priv->pv[x + y*W][0]= u;
             priv->pv[x + y*W][1]= v;
         }
     }
 }

 static double getCoeff(double d){
     double A= -0.60;
     double coeff;

     d= fabs(d);

     // Equation is from VirtualDub
     if(d<1.0)
         coeff = (1.0 - (A+3.0)*d*d + (A+2.0)*d*d*d);
     else if(d<2.0)
         coeff = (-4.0*A + 8.0*A*d - 5.0*A*d*d + A*d*d*d);
     else
         coeff=0.0;

     return coeff;
 }

 static int config(struct vf_instance *vf,
     int width, int height, int d_width, int d_height,
     unsigned int flags, unsigned int outfmt){
     int i, j;

     vf->priv->pvStride= width;
     vf->priv->pv= av_malloc(width*height*2*sizeof(int32_t));
     initPv(vf->priv, width, height);

     for(i=0; i<SUB_PIXELS; i++){
         double d= i/(double)SUB_PIXELS;
         double temp[4];
         double sum=0;

         for(j=0; j<4; j++)
             temp[j]= getCoeff(j - d - 1);

         for(j=0; j<4; j++)
             sum+= temp[j];

         for(j=0; j<4; j++)
             vf->priv->coeff[i][j]= (int)floor((1<<COEFF_BITS)*temp[j]/sum + 0.5);
     }

     return vf_next_config(vf,width,height,d_width,d_height,flags,outfmt);
 }

 static void uninit(struct vf_instance *vf){
     if(!vf->priv) return;

     av_free(vf->priv->pv);
     vf->priv->pv= NULL;

     free(vf->priv);
     vf->priv=NULL;
 }

 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){
     int x, y;
     struct vf_priv_s priv= *privParam;

     for(y=0; y<h; y++){
         for(x=0; x<w; x++){
             int u, v, subU, subV, sum, sx, sy;

             sx= x << xShift;
             sy= y << yShift;
             u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
             v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
             subU= u & (SUB_PIXELS-1);
             subV= v & (SUB_PIXELS-1);
             u >>= SUB_PIXEL_BITS;
             v >>= SUB_PIXEL_BITS;

             if(u>0 && v>0 && u<w-2 && v<h-2){
                 const int index= u + v*srcStride;
                 const int a= priv.coeff[subU][0];
                 const int b= priv.coeff[subU][1];
                 const int c= priv.coeff[subU][2];
                 const int d= priv.coeff[subU][3];

                 sum=
                  priv.coeff[subV][0]*(  a*src[index - 1 - srcStride] + b*src[index - 0 - srcStride]
                                       + c*src[index + 1 - srcStride] + d*src[index + 2 - srcStride])
                 +priv.coeff[subV][1]*(  a*src[index - 1            ] + b*src[index - 0            ]
                                       + c*src[index + 1            ] + d*src[index + 2            ])
                 +priv.coeff[subV][2]*(  a*src[index - 1 + srcStride] + b*src[index - 0 + srcStride]
                                       + c*src[index + 1 + srcStride] + d*src[index + 2 + srcStride])
                 +priv.coeff[subV][3]*(  a*src[index - 1+2*srcStride] + b*src[index - 0+2*srcStride]
                                       + c*src[index + 1+2*srcStride] + d*src[index + 2+2*srcStride]);
             }else{
                 int dx, dy;
                 sum=0;

                 for(dy=0; dy<4; dy++){
                     int iy= v + dy - 1;
                     if     (iy< 0) iy=0;
                     else if(iy>=h) iy=h-1;
                     for(dx=0; dx<4; dx++){
                         int ix= u + dx - 1;
                         if     (ix< 0) ix=0;
                         else if(ix>=w) ix=w-1;

                         sum+=  priv.coeff[subU][dx]*priv.coeff[subV][dy]
                               *src[ ix + iy*srcStride];
                     }
                 }
             }
             sum= (sum + (1<<(COEFF_BITS*2-1)) ) >> (COEFF_BITS*2);
             if(sum&~255){
                 if(sum<0) sum=0;
                 else      sum=255;
             }
             dst[ x + y*dstStride]= sum;
         }
     }
 }

 static inline void resampleLinear(uint8_t *dst, uint8_t *src, int w, int h, int dstStride, int srcStride,
                   struct vf_priv_s *privParam, int xShift, int yShift){
     int x, y;
     struct vf_priv_s priv= *privParam;

     for(y=0; y<h; y++){
         for(x=0; x<w; x++){
             int u, v, subU, subV, sum, sx, sy, index, subUI, subVI;

             sx= x << xShift;
             sy= y << yShift;
             u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
             v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
             subU= u & (SUB_PIXELS-1);
             subV= v & (SUB_PIXELS-1);
             u >>= SUB_PIXEL_BITS;
             v >>= SUB_PIXEL_BITS;
             index= u + v*srcStride;
             subUI= SUB_PIXELS - subU;
             subVI= SUB_PIXELS - subV;

             if((unsigned)u < (unsigned)(w - 1)){
                 if((unsigned)v < (unsigned)(h - 1)){
                     sum= subVI*(subUI*src[index          ] + subU*src[index          +1])
                         +subV *(subUI*src[index+srcStride] + subU*src[index+srcStride+1]);
                     sum= (sum + (1<<(SUB_PIXEL_BITS*2-1)) ) >> (SUB_PIXEL_BITS*2);
                 }else{
                     if(v<0) v= 0;
                     else    v= h-1;
                     index= u + v*srcStride;
                     sum= subUI*src[index] + subU*src[index+1];
                     sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
                 }
             }else{
                 if((unsigned)v < (unsigned)(h - 1)){
                     if(u<0) u= 0;
                     else    u= w-1;
                     index= u + v*srcStride;
                     sum= subVI*src[index] + subV*src[index+srcStride];
                     sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
                 }else{
                     if(u<0) u= 0;
                     else    u= w-1;
                     if(v<0) v= 0;
                     else    v= h-1;
                     index= u + v*srcStride;
                     sum= src[index];
                 }
             }
             if(sum&~255){
                 if(sum<0) sum=0;
                 else      sum=255;
             }
             dst[ x + y*dstStride]= sum;
         }
     }
 }

 static int put_image(struct vf_instance *vf, mp_image_t *mpi, double pts){
     int cw= mpi->w >> mpi->chroma_x_shift;
     int ch= mpi->h >> mpi->chroma_y_shift;

     mp_image_t *dmpi=vf_get_image(vf->next,mpi->imgfmt,
         MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
         mpi->w,mpi->h);

     assert(mpi->flags&MP_IMGFLAG_PLANAR);

     if(vf->priv->cubic){
         resampleCubic(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
                 vf->priv, 0, 0);
         resampleCubic(dmpi->planes[1], mpi->planes[1], cw    , ch   , dmpi->stride[1], mpi->stride[1],
                 vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
         resampleCubic(dmpi->planes[2], mpi->planes[2], cw    , ch   , dmpi->stride[2], mpi->stride[2],
                 vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
     }else{
         resampleLinear(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
                 vf->priv, 0, 0);
         resampleLinear(dmpi->planes[1], mpi->planes[1], cw    , ch   , dmpi->stride[1], mpi->stride[1],
                 vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
         resampleLinear(dmpi->planes[2], mpi->planes[2], cw    , ch   , dmpi->stride[2], mpi->stride[2],
                 vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
     }

     return vf_next_put_image(vf,dmpi, pts);
 }

 //===========================================================================//

 static int query_format(struct vf_instance *vf, unsigned int fmt){
     switch(fmt)
     {
     case IMGFMT_YV12:
     case IMGFMT_I420:
     case IMGFMT_IYUV:
     case IMGFMT_YVU9:
     case IMGFMT_444P:
     case IMGFMT_422P:
     case IMGFMT_411P:
         return vf_next_query_format(vf, fmt);
     }
     return 0;
 }

 static int vf_open(vf_instance_t *vf, char *args){
     int e;

     vf->config=config;
     vf->put_image=put_image;
 //  vf->get_image=get_image;
     vf->query_format=query_format;
     vf->uninit=uninit;
     vf->priv=malloc(sizeof(struct vf_priv_s));
     memset(vf->priv, 0, sizeof(struct vf_priv_s));

     if(args==NULL) return 0;

     e=sscanf(args, "%lf:%lf:%lf:%lf:%lf:%lf:%lf:%lf:%d",
         &vf->priv->ref[0][0], &vf->priv->ref[0][1],
         &vf->priv->ref[1][0], &vf->priv->ref[1][1],
         &vf->priv->ref[2][0], &vf->priv->ref[2][1],
         &vf->priv->ref[3][0], &vf->priv->ref[3][1],
         &vf->priv->cubic
         );

     if(e!=9)
         return 0;

     return 1;
 }

 const vf_info_t vf_info_perspective = {
     "perspective correcture",
     "perspective",
     "Michael Niedermayer",
     "",
     vf_open,
     NULL
 };

 //===========================================================================//
	/*
	* Copyright (C) 2002 Michael Niedermayer <michaelni@gmx.at>
	*
	* This file is part of MPlayer.
	*
	* MPlayer is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* MPlayer 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 General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with MPlayer; if not, write to the Free Software Foundation, Inc.,
	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <inttypes.h>
	#include <assert.h>
	#include <math.h>

	#include "config.h"
	#include "mp_msg.h"

	#if HAVE_MALLOC_H
	#include <malloc.h>
	#endif

	#include "libavutil/mem.h"

	#include "img_format.h"
	#include "mp_image.h"
	#include "vf.h"

	#define SUB_PIXEL_BITS 8
	#define SUB_PIXELS (1<<SUB_PIXEL_BITS)
	#define COEFF_BITS 11

	//===========================================================================//

	struct vf_priv_s {
	double ref[4][2];
	int32_t coeff[1<<SUB_PIXEL_BITS][4];
	int32_t (*pv)[2];
	int pvStride;
	int cubic;
	};


	/***************************************************************************/

	static void initPv(struct vf_priv_s *priv, int W, int H){
	double a,b,c,d,e,f,g,h,D;
	double (*ref)[2]= priv->ref;
	int x,y;

	g= ( (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])*(ref[2][1] - ref[3][1])
	- (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])(ref[2][0] - ref[3][0]))H;
	h= ( (ref[0][1] - ref[1][1] - ref[2][1] + ref[3][1])*(ref[1][0] - ref[3][0])
	- (ref[0][0] - ref[1][0] - ref[2][0] + ref[3][0])(ref[1][1] - ref[3][1]))W;
	D= (ref[1][0] - ref[3][0])*(ref[2][1] - ref[3][1])
	- (ref[2][0] - ref[3][0])*(ref[1][1] - ref[3][1]);

	a= D(ref[1][0] - ref[0][0])H + g*ref[1][0];
	b= D(ref[2][0] - ref[0][0])W + h*ref[2][0];
	c= Dref[0][0]W*H;
	d= D(ref[1][1] - ref[0][1])H + g*ref[1][1];
	e= D(ref[2][1] - ref[0][1])W + h*ref[2][1];
	f= Dref[0][1]W*H;

	for(y=0; y<H; y++){
	for(x=0; x<W; x++){
	int u, v;

	u= (int)floor( SUB_PIXELS(ax + by + c)/(gx + hy + DW*H) + 0.5);
	v= (int)floor( SUB_PIXELS(dx + ey + f)/(gx + hy + DW*H) + 0.5);

	priv->pv[x + y*W][0]= u;
	priv->pv[x + y*W][1]= v;
	}
	}
	}

	static double getCoeff(double d){
	double A= -0.60;
	double coeff;

	d= fabs(d);

	// Equation is from VirtualDub
	if(d<1.0)
	coeff = (1.0 - (A+3.0)dd + (A+2.0)dd*d);
	else if(d<2.0)
	coeff = (-4.0A + 8.0Ad - 5.0Add + Add*d);
	else
	coeff=0.0;

	return coeff;
	}

	static int config(struct vf_instance *vf,
	int width, int height, int d_width, int d_height,
	unsigned int flags, unsigned int outfmt){
	int i, j;

	vf->priv->pvStride= width;
	vf->priv->pv= av_malloc(widthheight2*sizeof(int32_t));
	initPv(vf->priv, width, height);

	for(i=0; i<SUB_PIXELS; i++){
	double d= i/(double)SUB_PIXELS;
	double temp[4];
	double sum=0;

	for(j=0; j<4; j++)
	temp[j]= getCoeff(j - d - 1);

	for(j=0; j<4; j++)
	sum+= temp[j];

	for(j=0; j<4; j++)
	vf->priv->coeff[i][j]= (int)floor((1<<COEFF_BITS)*temp[j]/sum + 0.5);
	}

	return vf_next_config(vf,width,height,d_width,d_height,flags,outfmt);
	}

	static void uninit(struct vf_instance *vf){
	if(!vf->priv) return;

	av_free(vf->priv->pv);
	vf->priv->pv= NULL;

	free(vf->priv);
	vf->priv=NULL;
	}

	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){
	int x, y;
	struct vf_priv_s priv= *privParam;

	for(y=0; y<h; y++){
	for(x=0; x<w; x++){
	int u, v, subU, subV, sum, sx, sy;

	sx= x << xShift;
	sy= y << yShift;
	u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
	v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
	subU= u & (SUB_PIXELS-1);
	subV= v & (SUB_PIXELS-1);
	u >>= SUB_PIXEL_BITS;
	v >>= SUB_PIXEL_BITS;

	if(u>0 && v>0 && u<w-2 && v<h-2){
	const int index= u + v*srcStride;
	const int a= priv.coeff[subU][0];
	const int b= priv.coeff[subU][1];
	const int c= priv.coeff[subU][2];
	const int d= priv.coeff[subU][3];

	sum=
	priv.coeff[subV][0]( asrc[index - 1 - srcStride] + b*src[index - 0 - srcStride]
	+ csrc[index + 1 - srcStride] + dsrc[index + 2 - srcStride])
	+priv.coeff[subV][1]( asrc[index - 1 ] + b*src[index - 0 ]
	+ csrc[index + 1 ] + dsrc[index + 2 ])
	+priv.coeff[subV][2]( asrc[index - 1 + srcStride] + b*src[index - 0 + srcStride]
	+ csrc[index + 1 + srcStride] + dsrc[index + 2 + srcStride])
	+priv.coeff[subV][3]( asrc[index - 1+2srcStride] + bsrc[index - 0+2*srcStride]
	+ csrc[index + 1+2srcStride] + dsrc[index + 2+2srcStride]);
	}else{
	int dx, dy;
	sum=0;

	for(dy=0; dy<4; dy++){
	int iy= v + dy - 1;
	if (iy< 0) iy=0;
	else if(iy>=h) iy=h-1;
	for(dx=0; dx<4; dx++){
	int ix= u + dx - 1;
	if (ix< 0) ix=0;
	else if(ix>=w) ix=w-1;

	sum+= priv.coeff[subU][dx]*priv.coeff[subV][dy]
	src[ ix + iysrcStride];
	}
	}
	}
	sum= (sum + (1<<(COEFF_BITS2-1)) ) >> (COEFF_BITS2);
	if(sum&~255){
	if(sum<0) sum=0;
	else sum=255;
	}
	dst[ x + y*dstStride]= sum;
	}
	}
	}

	static inline void resampleLinear(uint8_t dst, uint8_t src, int w, int h, int dstStride, int srcStride,
	struct vf_priv_s *privParam, int xShift, int yShift){
	int x, y;
	struct vf_priv_s priv= *privParam;

	for(y=0; y<h; y++){
	for(x=0; x<w; x++){
	int u, v, subU, subV, sum, sx, sy, index, subUI, subVI;

	sx= x << xShift;
	sy= y << yShift;
	u= priv.pv[sx + sy*priv.pvStride][0]>>xShift;
	v= priv.pv[sx + sy*priv.pvStride][1]>>yShift;
	subU= u & (SUB_PIXELS-1);
	subV= v & (SUB_PIXELS-1);
	u >>= SUB_PIXEL_BITS;
	v >>= SUB_PIXEL_BITS;
	index= u + v*srcStride;
	subUI= SUB_PIXELS - subU;
	subVI= SUB_PIXELS - subV;

	if((unsigned)u < (unsigned)(w - 1)){
	if((unsigned)v < (unsigned)(h - 1)){
	sum= subVI(subUIsrc[index ] + subU*src[index +1])
	+subV (subUIsrc[index+srcStride] + subU*src[index+srcStride+1]);
	sum= (sum + (1<<(SUB_PIXEL_BITS2-1)) ) >> (SUB_PIXEL_BITS2);
	}else{
	if(v<0) v= 0;
	else v= h-1;
	index= u + v*srcStride;
	sum= subUIsrc[index] + subUsrc[index+1];
	sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
	}
	}else{
	if((unsigned)v < (unsigned)(h - 1)){
	if(u<0) u= 0;
	else u= w-1;
	index= u + v*srcStride;
	sum= subVIsrc[index] + subVsrc[index+srcStride];
	sum= (sum + (1<<(SUB_PIXEL_BITS-1)) ) >> SUB_PIXEL_BITS;
	}else{
	if(u<0) u= 0;
	else u= w-1;
	if(v<0) v= 0;
	else v= h-1;
	index= u + v*srcStride;
	sum= src[index];
	}
	}
	if(sum&~255){
	if(sum<0) sum=0;
	else sum=255;
	}
	dst[ x + y*dstStride]= sum;
	}
	}
	}

	static int put_image(struct vf_instance vf, mp_image_t mpi, double pts){
	int cw= mpi->w >> mpi->chroma_x_shift;
	int ch= mpi->h >> mpi->chroma_y_shift;

	mp_image_t *dmpi=vf_get_image(vf->next,mpi->imgfmt,
	MP_IMGTYPE_TEMP, MP_IMGFLAG_ACCEPT_STRIDE,
	mpi->w,mpi->h);

	assert(mpi->flags&MP_IMGFLAG_PLANAR);

	if(vf->priv->cubic){
	resampleCubic(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
	vf->priv, 0, 0);
	resampleCubic(dmpi->planes[1], mpi->planes[1], cw , ch , dmpi->stride[1], mpi->stride[1],
	vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
	resampleCubic(dmpi->planes[2], mpi->planes[2], cw , ch , dmpi->stride[2], mpi->stride[2],
	vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
	}else{
	resampleLinear(dmpi->planes[0], mpi->planes[0], mpi->w,mpi->h, dmpi->stride[0], mpi->stride[0],
	vf->priv, 0, 0);
	resampleLinear(dmpi->planes[1], mpi->planes[1], cw , ch , dmpi->stride[1], mpi->stride[1],
	vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
	resampleLinear(dmpi->planes[2], mpi->planes[2], cw , ch , dmpi->stride[2], mpi->stride[2],
	vf->priv, mpi->chroma_x_shift, mpi->chroma_y_shift);
	}

	return vf_next_put_image(vf,dmpi, pts);
	}

	//===========================================================================//

	static int query_format(struct vf_instance *vf, unsigned int fmt){
	switch(fmt)
	{
	case IMGFMT_YV12:
	case IMGFMT_I420:
	case IMGFMT_IYUV:
	case IMGFMT_YVU9:
	case IMGFMT_444P:
	case IMGFMT_422P:
	case IMGFMT_411P:
	return vf_next_query_format(vf, fmt);
	}
	return 0;
	}

	static int vf_open(vf_instance_t vf, char args){
	int e;

	vf->config=config;
	vf->put_image=put_image;
	// vf->get_image=get_image;
	vf->query_format=query_format;
	vf->uninit=uninit;
	vf->priv=malloc(sizeof(struct vf_priv_s));
	memset(vf->priv, 0, sizeof(struct vf_priv_s));

	if(args==NULL) return 0;

	e=sscanf(args, "%lf:%lf:%lf:%lf:%lf:%lf:%lf:%lf:%d",
	&vf->priv->ref[0][0], &vf->priv->ref[0][1],
	&vf->priv->ref[1][0], &vf->priv->ref[1][1],
	&vf->priv->ref[2][0], &vf->priv->ref[2][1],
	&vf->priv->ref[3][0], &vf->priv->ref[3][1],
	&vf->priv->cubic
	);

	if(e!=9)
	return 0;

	return 1;
	}

	const vf_info_t vf_info_perspective = {
	"perspective correcture",
	"perspective",
	"Michael Niedermayer",
	"",
	vf_open,
	NULL
	};

	//===========================================================================//