diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 27e8e0c261..9ecaa287bb 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -3896,7 +3896,7 @@ static int mxf_get_next_track_edit_unit(MXFContext *mxf, MXFTrack *track, int64_
     a = -1;
     b = track->original_duration;
     while (b - 1 > a) {
-        m = (a + b) >> 1;
+        m = (a + (uint64_t)b) >> 1;
         if (mxf_edit_unit_absolute_offset(mxf, t, m, track->edit_rate, NULL, &offset, NULL, 0) < 0)
             return -1;
         if (offset < current_offset)