static int config(struct vf_instance *vf, int width, int height, int d_width, int d_height, unsigned int flags, unsigned int outfmt) { switch (vf->priv->mode) { case 0: case 3: return ff_vf_next_config(vf,width,height*2,d_width,d_height*2,flags,outfmt); case 1: /* odd frames */ case 2: /* even frames */ case 4: /* alternate frame (height-preserving) interlacing */ return ff_vf_next_config(vf,width,height,d_width,d_height,flags,outfmt); } return 0; }