确保ntp时间戳获取失败时，webrtc rtp重传缓存列队长度正常

src/Rtsp/Rtsp.cpp

@@ -538,8 +538,8 @@ uint32_t RtpPacket::getStamp() const {
     return ntohl(getHeader()->stamp);
 }
 
-uint32_t RtpPacket::getStampMS() const {
-    return ntp_stamp & 0xFFFFFFFF;
+uint32_t RtpPacket::getStampMS(bool ntp) const {
+    return ntp ? ntp_stamp & 0xFFFFFFFF : getStamp() * uint64_t(1000) / sample_rate;
 }
 
 uint32_t RtpPacket::getSSRC() const {

src/Rtsp/Rtsp.h

@@ -159,7 +159,7 @@ public:
     uint16_t getSeq() const;
     uint32_t getStamp() const;
     //主机字节序的时间戳，已经转换为毫秒
-    uint32_t getStampMS() const;
+    uint32_t getStampMS(bool ntp = true) const;
     //主机字节序的ssrc
     uint32_t getSSRC() const;
     //有效负载，跳过csrc、ext

webrtc/Nack.cpp

@@ -60,8 +60,8 @@ uint32_t NackList::get_cache_ms() {
     if (_nack_cache_seq.size() < 2) {
         return 0;
     }
-    uint32_t back = _nack_cache_pkt[_nack_cache_seq.back()]->getStampMS();
-    uint32_t front = _nack_cache_pkt[_nack_cache_seq.front()]->getStampMS();
+    uint32_t back = _nack_cache_pkt[_nack_cache_seq.back()]->getStampMS(false);
+    uint32_t front = _nack_cache_pkt[_nack_cache_seq.front()]->getStampMS(false);
     if (back >= front) {
         return back - front;
     }