title: FU-A multiple slice NALU per frame RTP packetization
body: <p>We are doing 2 slices per frame encoding using our codec and we are getting good H264 file output when played on VLC player.
  <br>But when we RTP packetize that encoded data and stream to VLC, it shows artifacts. If we use one slice per frame, our packetization is ok and stream on VLC also looks good.
  <br>We are using FU-A fragmentation, and my encoded file configuration:</p>
  
  <pre><code>resolution: 640x480
  framerate: 30fps
  bitrate: 800 Kbps
  </code></pre>
  
  <p>Our encoder is configured to use High Profile, CBR, IDR every 10 frames.</p>
  
  <p>Our encoder output bitstream looks like:</p>
  
  <p><code>00 00 00 01 67 [DATA] 00 00 00 01 68 [DATA] 00 00 00 01 65 [DATA] 00 00 00 01 65 [DATA] 00 00 00 01 41 [DATA]</code></p>
  
  <p>So here we have two successive slice NALUs (0x65).
  In our RTP pcap, everything looks good -- FU-A fragmentation, marker bit, etc but VLC and ffplay both show a similar type of artifact, as if the upper half of the frame is stretched (vertically).
  <br>My pcap file link:
  <br><a href="http://www.filedropper.com/rtp" rel="nofollow">http://www.filedropper.com/rtp</a> </p>
  
  <p>So I reduced the test case to a small, low bitrate (50 Kbps) QCIF stream with no fragmentation and I am still seeing the same problem.
  <br>My pcap file link:
  <br><a href="http://www.filedropper.com/rtpqcif" rel="nofollow">http://www.filedropper.com/rtpqcif</a></p>
  
  <p><br>Can any expert please look at the pcap file and see what might be causing VLC such trouble to play stream? </p>
  
  <p>Thank you,
  <br>Harshal Patel</p>