<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div style="font-family: Calibri, sans-serif; font-size: 14px; ">All,</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">I'm working on a project where I need to consume H.264 data streamed from a webcam via RTSP. This is remarkably easy with Live555! Many thanks to Ross and everyone else. I'm currently confused by a particular sequence of NAL units that I see in the stream over and over and was hoping that someone more knowledgeable than myself might have some insight for me. Here's some output from a DummySink:</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 10547 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.138589!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">audio/PCMU:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 1024 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.189569!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 10962 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.178622!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 8651 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.218655!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 10621 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.258688!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 45 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span> Presentation time: 1379699108.258688!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 4 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span> Presentation time: 1379699108.258688!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 79400 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.298721!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">audio/PCMU:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 1024 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699108.317569!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">...</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 10486 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.139414!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">audio/PCMU:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 1024 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.213569!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 11426 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.179447!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 8681 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.219480!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 10878 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.259513!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 45 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span> Presentation time: 1379699109.259513!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 4 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span> Presentation time: 1379699109.259513!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">video/H264:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 82291 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.299546!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">audio/PCMU:<span class="Apple-tab-span" style="white-space: pre; "> </span>Received 1024 bytes.<span class="Apple-tab-span" style="white-space: pre; "> </span>Presentation time: 1379699109.341569!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">etc....</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">What are the 45 and 4 byte NAL units that share the same presentation time as the preceding H.264 NAL unit? </div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">The payload of these 45 and 4 byte units is identical in every case:</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><674d0029 9a6280f0 044fcb35 01010140 0000fa40 003a983a 1800bb80 002ee06e f2e34300 17700005 dc0dde5c 28></div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">and:</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><68ee3c80></div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">respectively. Neither appears to be a start code or delimiter? I'm definitely outside of my sphere of knowledge, so any advice would be appreciated.</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">Thanks!</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div><div style="font-family: Calibri, sans-serif; font-size: 14px; ">Mike</div><div style="font-family: Calibri, sans-serif; font-size: 14px; "><br></div></body></html>