diff --git a/libavformat/rtpenc.c b/libavformat/rtpenc.c
index 9e62c6571f..19e4f19fe4 100644
--- a/libavformat/rtpenc.c
+++ b/libavformat/rtpenc.c
@@ -33,6 +33,13 @@
 //#define DEBUG
 
 #define RTCP_SR_SIZE 28
+#define NTP_OFFSET 2208988800ULL
+#define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)
+
+static uint64_t ntp_time(void)
+{
+  return (av_gettime() / 1000) * 1000 + NTP_OFFSET_US;
+}
 
 static int rtp_write_header(AVFormatContext *s1)
 {
@@ -301,8 +308,8 @@ static int rtp_write_packet(AVFormatContext *s1, AVPacket *pkt)
     rtcp_bytes = ((s->octet_count - s->last_octet_count) * RTCP_TX_RATIO_NUM) /
         RTCP_TX_RATIO_DEN;
     if (s->first_packet || ((rtcp_bytes >= RTCP_SR_SIZE) &&
-                           (av_gettime() - s->last_rtcp_ntp_time > 5000000))) {
-        rtcp_send_sr(s1, av_gettime());
+                           (ntp_time() - s->last_rtcp_ntp_time > 5000000))) {
+        rtcp_send_sr(s1, ntp_time());
         s->last_octet_count = s->octet_count;
         s->first_packet = 0;
     }