diff --git a/ZLToolKit b/ZLToolKit
index 976f2e4b..d7487e37 160000
--- a/ZLToolKit
+++ b/ZLToolKit
@@ -1 +1 @@
-Subproject commit 976f2e4bb3b663b19a18781b38b44b43ba3598d8
+Subproject commit d7487e37dd915e8391c1d6a45f1773af13b366a7
diff --git a/src/Rtmp/FlvMuxer.cpp b/src/Rtmp/FlvMuxer.cpp
index 08f67a88..c648ca16 100644
--- a/src/Rtmp/FlvMuxer.cpp
+++ b/src/Rtmp/FlvMuxer.cpp
@@ -106,7 +106,7 @@ public:
     BufferRtmp(const RtmpPacket::Ptr & pkt):_rtmp(pkt){}
     virtual ~BufferRtmp(){}
 
-    char *data() override {
+    char *data() const override {
         return (char *)_rtmp->strBuf.data();
     }
     uint32_t size() const override {
diff --git a/src/Rtsp/RtspSession.h b/src/Rtsp/RtspSession.h
index 8b08060a..1748d327 100644
--- a/src/Rtsp/RtspSession.h
+++ b/src/Rtsp/RtspSession.h
@@ -59,7 +59,7 @@ public:
     BufferRtp(const RtpPacket::Ptr & pkt,uint32_t offset = 0 ):_rtp(pkt),_offset(offset){}
     virtual ~BufferRtp(){}
 
-    char *data() override {
+    char *data() const override {
         return (char *)_rtp->payload + _offset;
     }
     uint32_t size() const override {