diff --git a/webrtc/video/end_to_end_tests.cc b/webrtc/video/end_to_end_tests.cc
index 89a395fea8..e5b12ce0b1 100644
--- a/webrtc/video/end_to_end_tests.cc
+++ b/webrtc/video/end_to_end_tests.cc
@@ -790,13 +790,19 @@ void EndToEndTest::DecodesRetransmittedFrame(bool enable_rtx, bool enable_red) {
       }
 
       EXPECT_EQ(kVideoSendSsrcs[0], header.ssrc)
-          << "Payload type " << static_cast<int>(header.payloadType)
-          << " not expected.";
+          << "Unexpected packet length " << length
+          << ", header_length " << header.headerLength
+          << ", padding_length " << header.paddingLength
+          << ", timestamp " << header.timestamp
+          << ", expected timestamp " << retransmitted_timestamp_
+          << ", payload type " << static_cast<int>(header.payloadType);
       EXPECT_EQ(payload_type_, header.payloadType);
 
       // Found the final packet of the frame to inflict loss to, drop this and
       // expect a retransmission.
       if (header.markerBit && ++marker_bits_observed_ == kDroppedFrameNumber) {
+        // This should be the only dropped packet.
+        EXPECT_EQ(0u, retransmitted_timestamp_);
         retransmitted_timestamp_ = header.timestamp;
         return DROP_PACKET;
       }