diff --git a/src/Rtcp/RtcpFCI.cpp b/src/Rtcp/RtcpFCI.cpp
index d03d1a60..44d22055 100644
--- a/src/Rtcp/RtcpFCI.cpp
+++ b/src/Rtcp/RtcpFCI.cpp
@@ -142,4 +142,30 @@ string FCI_REMB::dumpString() const {
     return printer;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+void FCI_NACK::net2Host() {
+    pid = ntohs(pid);
+    blp = ntohs(blp);
+}
+
+vector<bool> FCI_NACK::getBitArray() const {
+    vector<bool> ret;
+    ret.resize(kBitSize);
+    for (size_t i = 0; i < kBitSize; ++i) {
+        ret[i] = blp & (1 << (kBitSize - i - 1));
+    }
+    return ret;
+}
+
+string FCI_NACK::dumpString() const {
+    _StrPrinter printer;
+    printer << "pid:" << pid << ",blp:";
+    for (auto &flag : getBitArray()) {
+        printer << flag << " ";
+    }
+    return std::move(printer);
+}
+
+
 }//namespace mediakit
\ No newline at end of file
diff --git a/src/Rtcp/RtcpFCI.h b/src/Rtcp/RtcpFCI.h
index f36056d9..ed216149 100644
--- a/src/Rtcp/RtcpFCI.h
+++ b/src/Rtcp/RtcpFCI.h
@@ -221,11 +221,31 @@ public:
 //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 class FCI_NACK {
 public:
+    static constexpr size_t kBitSize = 16;
+
     // The PID field is used to specify a lost packet.  The PID field
     //      refers to the RTP sequence number of the lost packet.
     uint16_t pid;
     // bitmask of following lost packets (BLP): 16 bits
     uint16_t blp;
+
+    void net2Host();
+    vector<bool> getBitArray() const;
+    string dumpString() const;
+
+    template<typename Type>
+    FCI_NACK(uint16_t pid_h, const Type &type){
+        uint16_t blp_h = 0;
+        int i = kBitSize;
+        for (auto &item : type) {
+            --i;
+            if (item) {
+                blp_h |= (1 << i);
+            }
+        }
+        blp = htons(blp_h);
+        pid = htons(pid_h);
+    }
 } PACKED;
 
 //RTPFB fmt = 3
diff --git a/tests/test_rtcp_fci.cpp b/tests/test_rtcp_fci.cpp
index c974d4b0..d8fd1eca 100644
--- a/tests/test_rtcp_fci.cpp
+++ b/tests/test_rtcp_fci.cpp
@@ -37,5 +37,10 @@ int main() {
         ptr->net2Host(str.size());
         InfoL << ptr->dumpString();
     }
+    {
+        FCI_NACK nack(1234, vector<int>({1, 0, 0, 0, 1, 0, 1, 0, 1, 0}));
+        nack.net2Host();
+        InfoL << nack.dumpString();
+    }
     return 0;
 }