diff --git a/webrtc/WebRtcEchoTest.cpp b/webrtc/WebRtcEchoTest.cpp
index 879c6ce7..1566ce53 100644
--- a/webrtc/WebRtcEchoTest.cpp
+++ b/webrtc/WebRtcEchoTest.cpp
@@ -24,6 +24,8 @@ WebRtcEchoTest::WebRtcEchoTest(const EventPoller::Ptr &poller) : WebRtcTransport
 void WebRtcEchoTest::onRtcConfigure(RtcConfigure &configure) const {
     WebRtcTransportImp::onRtcConfigure(configure);
     configure.audio.direction = configure.video.direction = RtpDirection::sendrecv;
+    configure.audio.extmap.emplace(RtpExtType::sdes_mid, RtpDirection::sendrecv);
+    configure.video.extmap.emplace(RtpExtType::sdes_mid, RtpDirection::sendrecv);
 }
 
 void WebRtcEchoTest::onRtp(const char *buf, size_t len, uint64_t stamp_ms) {