Index: vf_cropdetect.c
===================================================================
RCS file: /cvsroot/mplayer/main/libmpcodecs/vf_cropdetect.c,v
retrieving revision 1.8
diff -u -b -B -r1.8 vf_cropdetect.c
--- vf_cropdetect.c	25 Oct 2003 18:37:34 -0000	1.8
+++ vf_cropdetect.c	2 Mar 2004 19:32:21 -0000
@@ -17,6 +17,7 @@
     int x1,y1,x2,y2;
     int limit;
     int fno;
+    int roundsize, roundpos;
 };
 
 static int checkline(unsigned char* src,int stride,int len,int bpp){
@@ -103,14 +104,29 @@
 	}
     }
 
-    x=(vf->priv->x1+1)&(~1);
-    y=(vf->priv->y1+1)&(~1);
+    {
+	int cw, ch, x1, y1;
     
-    printf("crop area: X: %d..%d  Y: %d..%d  (-vf crop=%d:%d:%d:%d)\n",
+	/* round top left to align chroma */
+	vf->priv->x1 = (vf->priv->x1 + vf->priv->roundpos - 1) / vf->priv->roundpos * vf->priv->roundpos;
+	vf->priv->y1 = (vf->priv->y1 + vf->priv->roundpos - 1) / vf->priv->roundpos * vf->priv->roundpos;
+
+	/* round the size */
+	cw = (vf->priv->x2 + 1 - vf->priv->x1) / vf->priv->roundsize * vf->priv->roundsize;
+	ch = (vf->priv->y2 + 1 - vf->priv->y1) / vf->priv->roundsize * vf->priv->roundsize;
+
+	/* center the section, round to the nearest lower chroma-aligned */
+	x1 = vf->priv->x1 + ((vf->priv->x2 + 1 - vf->priv->x1) - cw) / 2 / vf->priv->roundpos * vf->priv->roundpos;
+	y1 = vf->priv->y1 + ((vf->priv->y2 + 1 - vf->priv->y1) - ch) / 2 / vf->priv->roundpos * vf->priv->roundpos;
+	
+	printf("crop area: X: %d..%d  Y: %d..%d, rnd: size %d px, pos %d px (-vf crop=%d:%d:%d:%d)\n",
 	vf->priv->x1,vf->priv->x2,
 	vf->priv->y1,vf->priv->y2,
-	(vf->priv->x2+1-x)&(~1),(vf->priv->y2+1-y)&(~1),x,y
+	       vf->priv->roundsize,
+	       vf->priv->roundpos,
+	       cw,ch,x1,y1
 	  );
+    }
 
 }
 
@@ -120,11 +136,17 @@
 //===========================================================================//
 
 static int open(vf_instance_t *vf, char* args){
+    int res;
+    
     vf->config=config;
     vf->put_image=put_image;
     vf->priv=malloc(sizeof(struct vf_priv_s));
-    vf->priv->limit=24; // should be option
-    if(args) vf->priv->limit=atoi(args);
+    vf->priv->limit=24;
+    vf->priv->roundsize=16;
+    vf->priv->roundpos=2;
+    if (args) res = sscanf(args, "%d:%d:%d", &vf->priv->limit, &vf->priv->roundsize, &vf->priv->roundpos);
+    if (vf->priv->roundsize < 1 || vf->priv->roundsize > 64) vf->priv->roundsize = 16;
+    if (vf->priv->roundpos < 1 || vf->priv->roundpos > 64) vf->priv->roundpos = 2;
     return 1;
 }