diff --git a/gst/isomp4/gstqtmux.c b/gst/isomp4/gstqtmux.c
index 3310aaa9d2..2b4a4e25f2 100644
--- a/gst/isomp4/gstqtmux.c
+++ b/gst/isomp4/gstqtmux.c
@@ -2155,6 +2155,9 @@ gst_qt_mux_add_buffer (GstQTMux * qtmux, GstQTPad * pad, GstBuffer * buf)
     if (GST_CLOCK_TIME_IS_VALID (GST_BUFFER_PTS (last_buf))) {
       pad->first_ts = GST_BUFFER_PTS (last_buf);
       check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (last_buf), pad->first_ts);
+      check_and_subtract_ts (qtmux, &GST_BUFFER_PTS (last_buf), pad->first_ts);
+      check_and_subtract_ts (qtmux, &GST_BUFFER_DTS (buf), pad->first_ts);
+      check_and_subtract_ts (qtmux, &GST_BUFFER_PTS (buf), pad->first_ts);
     } else {
       GST_ERROR_OBJECT (qtmux, "First buffer for pad %s has no timestamp, "
           "using 0 as first timestamp", GST_PAD_NAME (pad->collect.pad));