title: Missing packets error when streaming rtsp to rtmp using ffmpeg
body: <p>I'm using ffmpeg to do RTSP to RTMP streaming, the input is an sdp file describing one video stream and one audio stream, when I test the RTSP using ffplay,it works fine</p>
  
  <pre><code>ffplay -protocol_whitelist "file,udp,rtp" -strict -2 -i media.sdp
  </code></pre>
  
  <p>but when I switch to ffmpeg to do streaming, I got lot of packet missing errors</p>
  
  <pre><code>ffmpeg -protocol_whitelist "file,udp,rtp" -strict -2  -i media.sdp   -c copy -f flv "rtmp://liveaddress"
  </code></pre>
  
  <p>error log:</p>
  
  <pre><code>[sdp @ 000001f1f4cea400] max delay reached. need to consume packet
  [sdp @ 000001f1f4cea400] RTP: missed 321 packets
  [sdp @ 000001f1f4cea400] max delay reached. need to consume 
  [sdp @ 000001f1f4cea400] RTP: missed 14 packets
  [sdp @ 000001f1f4cea400] max delay reached. need to consume packet
  [sdp @ 000001f1f4cea400] RTP: missed 7 packets
  </code></pre>
  
  <p>the sdp file:</p>
  
  <pre><code>SDP:
  v=0
  o=- 0 0 IN IP4 127.0.0.1
  s=No Name
  t=0 0
  a=tool:libavformat 58.12.100
  m=video 5555 RTP/AVP 96
  c=IN IP4 127.0.0.1
  b=AS:2000
  a=rtpmap:96 H264/90000
  a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z0LAINoBQBbsBagICAoAAAfSAAOpgR4wZUA=,aM4fIA==; profile-level-id=42c020
  m=audio 6666 RTP/AVP 96
  c=IN IP4 127.0.0.1
  b=AS:125
  a=rtpmap:96 MPEG4-GENERIC/44100/2
  a=fmtp:96 profile-level-id=1;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3; config=1210
  </code></pre>