diff --git a/trunk/src/app/srs_app_rtc_source.cpp b/trunk/src/app/srs_app_rtc_source.cpp
index 4fcc03cb9..7d6d1e529 100644
--- a/trunk/src/app/srs_app_rtc_source.cpp
+++ b/trunk/src/app/srs_app_rtc_source.cpp
@@ -1710,12 +1710,11 @@ srs_error_t SrsRtcRecvTrack::on_nack(SrsRtpPacket2* pkt)
     return err;
 }
 
-srs_error_t SrsRtcRecvTrack::check_send_nacks()
+srs_error_t SrsRtcRecvTrack::do_check_send_nacks(uint32_t& timeout_nacks)
 {
     srs_error_t err = srs_success;
 
     uint32_t sent_nacks = 0;
-    uint32_t timeout_nacks = 0;
     session_->check_send_nacks(nack_receiver_, track_desc_->ssrc_, sent_nacks, timeout_nacks);
     statistic_->nacks += sent_nacks;
 
@@ -1754,6 +1753,18 @@ srs_error_t SrsRtcAudioRecvTrack::on_rtp(SrsRtcStream* source, SrsRtpPacket2* pk
     return err;
 }
 
+srs_error_t SrsRtcAudioRecvTrack::check_send_nacks()
+{
+    srs_error_t err = srs_success;
+
+    uint32_t timeout_nacks = 0;
+    if ((err = do_check_send_nacks(timeout_nacks)) != srs_success) {
+        return srs_error_wrap(err, "audio");
+    }
+
+    return err;
+}
+
 SrsRtcVideoRecvTrack::SrsRtcVideoRecvTrack(SrsRtcConnection* session, SrsRtcTrackDescription* track_desc)
     : SrsRtcRecvTrack(session, track_desc, false)
 {
@@ -1800,6 +1811,26 @@ srs_error_t SrsRtcVideoRecvTrack::on_rtp(SrsRtcStream* source, SrsRtpPacket2* pk
     return err;
 }
 
+srs_error_t SrsRtcVideoRecvTrack::check_send_nacks()
+{
+    srs_error_t err = srs_success;
+
+    uint32_t timeout_nacks = 0;
+    if ((err = do_check_send_nacks(timeout_nacks)) != srs_success) {
+        return srs_error_wrap(err, "video");
+    }
+
+    // If NACK timeout, start PLI if not requesting.
+    if (timeout_nacks == 0 || request_key_frame_) {
+        return err;
+    }
+
+    srs_trace("[Maybe] RTC: NACK timeout=%u, request PLI, track=%s, ssrc=%u", timeout_nacks,
+        track_desc_->id_.c_str(), track_desc_->ssrc_);
+
+    return err;
+}
+
 void SrsRtcVideoRecvTrack::request_keyframe()
 {
     cid_of_subscriber_ = _srs_context->get_id();
diff --git a/trunk/src/app/srs_app_rtc_source.hpp b/trunk/src/app/srs_app_rtc_source.hpp
index 31528b97c..e692610fe 100644
--- a/trunk/src/app/srs_app_rtc_source.hpp
+++ b/trunk/src/app/srs_app_rtc_source.hpp
@@ -501,7 +501,9 @@ protected:
     srs_error_t on_nack(SrsRtpPacket2* pkt);
 public:
     virtual srs_error_t on_rtp(SrsRtcStream* source, SrsRtpPacket2* pkt) = 0;
-    virtual srs_error_t check_send_nacks();
+    virtual srs_error_t check_send_nacks() = 0;
+protected:
+    virtual srs_error_t do_check_send_nacks(uint32_t& timeout_nacks);
 };
 
 class SrsRtcAudioRecvTrack : public SrsRtcRecvTrack
@@ -511,6 +513,7 @@ public:
     virtual ~SrsRtcAudioRecvTrack();
 public:
     virtual srs_error_t on_rtp(SrsRtcStream* source, SrsRtpPacket2* pkt);
+    virtual srs_error_t check_send_nacks();
 };
 
 class SrsRtcVideoRecvTrack : public SrsRtcRecvTrack
@@ -524,6 +527,7 @@ public:
     virtual ~SrsRtcVideoRecvTrack();
 public:
     virtual srs_error_t on_rtp(SrsRtcStream* source, SrsRtpPacket2* pkt);
+    virtual srs_error_t check_send_nacks();
 public:
     void request_keyframe();
 };