diff --git a/modules/rtp_rtcp/source/rtp_sender_video.cc b/modules/rtp_rtcp/source/rtp_sender_video.cc
index ea920ecd41..31002aa0df 100644
--- a/modules/rtp_rtcp/source/rtp_sender_video.cc
+++ b/modules/rtp_rtcp/source/rtp_sender_video.cc
@@ -399,7 +399,8 @@ bool RTPSenderVideo::SendVideo(
     int64_t capture_time_ms,
     rtc::ArrayView<const uint8_t> payload,
     RTPVideoHeader video_header,
-    absl::optional<int64_t> expected_retransmission_time_ms) {
+    absl::optional<int64_t> expected_retransmission_time_ms,
+    absl::optional<int64_t> estimated_capture_clock_offset_ms) {
 #if RTC_TRACE_EVENTS_ENABLED
   TRACE_EVENT_ASYNC_STEP1("webrtc", "Video", capture_time_ms, "Send", "type",
                           FrameTypeToString(video_header.frame_type));
@@ -452,7 +453,7 @@ bool RTPSenderVideo::SendVideo(
           single_packet->Timestamp(), kVideoPayloadTypeFrequency,
           Int64MsToUQ32x32(single_packet->capture_time_ms() + NtpOffsetMs()),
           /*estimated_capture_clock_offset=*/
-          include_capture_clock_offset_ ? absl::make_optional(0)
+          include_capture_clock_offset_ ? estimated_capture_clock_offset_ms
                                         : absl::nullopt);
 
   auto first_packet = std::make_unique<RtpPacketToSend>(*single_packet);
diff --git a/modules/rtp_rtcp/source/rtp_sender_video.h b/modules/rtp_rtcp/source/rtp_sender_video.h
index e82496c3d4..4addb094dd 100644
--- a/modules/rtp_rtcp/source/rtp_sender_video.h
+++ b/modules/rtp_rtcp/source/rtp_sender_video.h
@@ -91,13 +91,19 @@ class RTPSenderVideo {
 
   // expected_retransmission_time_ms.has_value() -> retransmission allowed.
   // Calls to this method is assumed to be externally serialized.
+  // |estimated_capture_clock_offset_ms| is an estimated clock offset between
+  // this sender and the original capturer, for this video packet. See
+  // http://www.webrtc.org/experiments/rtp-hdrext/abs-capture-time for more
+  // details. If the sender and the capture has the same clock, it is supposed
+  // to be zero valued, which is given as the default.
   bool SendVideo(int payload_type,
                  absl::optional<VideoCodecType> codec_type,
                  uint32_t rtp_timestamp,
                  int64_t capture_time_ms,
                  rtc::ArrayView<const uint8_t> payload,
                  RTPVideoHeader video_header,
-                 absl::optional<int64_t> expected_retransmission_time_ms);
+                 absl::optional<int64_t> expected_retransmission_time_ms,
+                 absl::optional<int64_t> estimated_capture_clock_offset_ms = 0);
 
   bool SendEncodedImage(
       int payload_type,
diff --git a/modules/rtp_rtcp/source/rtp_sender_video_unittest.cc b/modules/rtp_rtcp/source/rtp_sender_video_unittest.cc
index bbd8caadba..b114cd271d 100644
--- a/modules/rtp_rtcp/source/rtp_sender_video_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_sender_video_unittest.cc
@@ -867,10 +867,12 @@ TEST_P(RtpSenderVideoTest, AbsoluteCaptureTimeWithCaptureClockOffset) {
                                           kAbsoluteCaptureTimeExtensionId);
 
   RTPVideoHeader hdr;
+  const absl::optional<int64_t> kExpectedCaptureClockOffset =
+      absl::make_optional(1234);
   hdr.frame_type = VideoFrameType::kVideoFrameKey;
-  rtp_sender_video_->SendVideo(kPayload, kType, kTimestamp,
-                               kAbsoluteCaptureTimestampMs, kFrame, hdr,
-                               kDefaultExpectedRetransmissionTimeMs);
+  rtp_sender_video_->SendVideo(
+      kPayload, kType, kTimestamp, kAbsoluteCaptureTimestampMs, kFrame, hdr,
+      kDefaultExpectedRetransmissionTimeMs, kExpectedCaptureClockOffset);
 
   // It is expected that one and only one of the packets sent on this video
   // frame has absolute capture time header extension. And it includes capture
@@ -883,9 +885,8 @@ TEST_P(RtpSenderVideoTest, AbsoluteCaptureTimeWithCaptureClockOffset) {
       ++packets_with_abs_capture_time;
       EXPECT_EQ(absolute_capture_time->absolute_capture_timestamp,
                 Int64MsToUQ32x32(kAbsoluteCaptureTimestampMs + NtpOffsetMs()));
-      EXPECT_TRUE(
-          absolute_capture_time->estimated_capture_clock_offset.has_value());
-      EXPECT_EQ(0, *absolute_capture_time->estimated_capture_clock_offset);
+      EXPECT_EQ(kExpectedCaptureClockOffset,
+                absolute_capture_time->estimated_capture_clock_offset);
     }
   }
   EXPECT_EQ(packets_with_abs_capture_time, 1);