Fix crash in subpictures rendering

src/video_output/vout_subpictures.c

@@ -528,10 +528,9 @@ void spu_RenderSubpictures( spu_t *p_spu, video_format_t *p_fmt,
                     p_fmt->i_height;
         }
 
-	if (p_subpic->p_region->fmt.i_aspect == 0)
+        if ( p_region && p_subpic->p_region->fmt.i_aspect == 0 )
           /* Set subtitle to be the same aspect ratio as the background
-	     source video.
-	   */
+             source video. */
             p_subpic->p_region->fmt.i_aspect = p_pic_src->format.i_aspect;
 
         i_scale_width = i_scale_width_orig;
@@ -547,8 +546,8 @@ void spu_RenderSubpictures( spu_t *p_spu, video_format_t *p_fmt,
         }
 
         /* Take care of the aspect ratio */
-
-	if( p_subpic->p_region->fmt.i_aspect != p_pic_src->format.i_aspect)
+        if( p_region && p_subpic->p_region->fmt.i_aspect !=
+                        p_pic_src->format.i_aspect)
         {
             i_scale_width = (p_subpic->p_region->fmt.i_aspect*1000) /
             p_pic_src->format.i_aspect;