diff --git a/src/Rtcp/RtcpContext.cpp b/src/Rtcp/RtcpContext.cpp
index d2afbc95..681c9d17 100644
--- a/src/Rtcp/RtcpContext.cpp
+++ b/src/Rtcp/RtcpContext.cpp
@@ -120,8 +120,10 @@ size_t RtcpContext::getExpectedPackets() const {
 size_t RtcpContextForRecv::getExpectedPackets() const {
     return (_seq_cycles << 16) + _seq_max - _seq_base + 1;
 }
-
 size_t RtcpContext::getExpectedPacketsInterval() {
+    throw std::runtime_error("没有实现, rtp发送者无法统计应收包数");
+}
+size_t RtcpContextForRecv::getExpectedPacketsInterval() {
     auto expected = getExpectedPackets();
     auto ret = expected - _last_expected;
     _last_expected = expected;
@@ -137,6 +139,9 @@ size_t RtcpContextForRecv::getLost() {
 }
 
 size_t RtcpContext::geLostInterval() {
+    throw std::runtime_error("没有实现, rtp发送者无法统计丢包率");
+}
+size_t RtcpContextForRecv::geLostInterval() {
     auto lost = getLost();
     auto ret = lost - _last_lost;
     _last_lost = lost;
diff --git a/src/Rtcp/RtcpContext.h b/src/Rtcp/RtcpContext.h
index b25a4ed3..c476219f 100644
--- a/src/Rtcp/RtcpContext.h
+++ b/src/Rtcp/RtcpContext.h
@@ -73,12 +73,12 @@ public:
     /**
      * 上次结果与本次结果间应收包数
      */
-    size_t getExpectedPacketsInterval();
+    virtual size_t getExpectedPacketsInterval();
 
     /**
      * 上次结果与本次结果间丢包个数
      */
-    size_t geLostInterval();
+    virtual size_t geLostInterval();
 
 protected:
     //收到或发送的rtp的字节数
@@ -124,7 +124,9 @@ public:
     void onRtp(uint16_t seq, uint32_t stamp, uint64_t ntp_stamp_ms, uint32_t sample_rate, size_t bytes) override;
     Buffer::Ptr createRtcpRR(uint32_t rtcp_ssrc, uint32_t rtp_ssrc) override;
     size_t getExpectedPackets() const override;
+    size_t getExpectedPacketsInterval() override;
     size_t getLost() override;
+    size_t geLostInterval() override;
 };
 }//namespace mediakit
 #endif //ZLMEDIAKIT_RTCPCONTEXT_H