* modules/video_filter/scale.c: Guard against p_pic->pf_release being NULL,...

* modules/video_filter/scale.c: Guard against p_pic->pf_release being NULL, which can happen e.g. if an unknown chroma is passed to the video output/filter

modules/video_filter/scale.c

@@ -114,7 +114,8 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
     if( !p_pic_dst )
     {
         msg_Warn( p_filter, "can't get output picture" );
-        p_pic->pf_release( p_pic );
+        if( p_pic->pf_release )
+            p_pic->pf_release( p_pic );
         return NULL;
     }