diff --git a/ffmpeg.c b/ffmpeg.c
index f6a9765d67..577425b79e 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1246,8 +1246,7 @@ static void do_video_out(AVFormatContext *s,
 
     format_video_sync = video_sync_method;
     if (format_video_sync < 0)
-        format_video_sync = (s->oformat->flags & AVFMT_NOTIMESTAMPS) ? 0 :
-                            (s->oformat->flags & AVFMT_VARIABLE_FPS) ? 2 : 1;
+        format_video_sync = (s->oformat->flags & AVFMT_VARIABLE_FPS) ? ((s->oformat->flags & AVFMT_NOTIMESTAMPS) ? 0 : 2) : 1;
 
     if (format_video_sync) {
         double vdelta = sync_ipts - ost->sync_opts + duration;
diff --git a/tests/ref/lavf/gxf b/tests/ref/lavf/gxf
index 6b39c2f273..68bc9785a2 100644
--- a/tests/ref/lavf/gxf
+++ b/tests/ref/lavf/gxf
@@ -1,3 +1,3 @@
 346d38d330ab5cb0caa6b5537167bc0d *./tests/data/lavf/lavf.gxf
 796392 ./tests/data/lavf/lavf.gxf
-./tests/data/lavf/lavf.gxf CRC=0x345f86eb
+./tests/data/lavf/lavf.gxf CRC=0x102918fd