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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#943634'>Thanks for the reply. I actually made that change about a year ago; I was aware that the code was already calculating presentation time for the purpose of synchronization, but for some reason I thought it was just a relative presentation time, not an absolute one that accurately reflected the time of frame capture. Looking at the code now though I’m not sure why I came to that conclusion as it definitely looks like it’s doing the right thing.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#943634'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#943634'>In which case please disregard my patch.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#943634'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> live-devel-bounces@ns.live555.com [mailto:live-devel-bounces@ns.live555.com] <b>On Behalf Of </b>Ross Finlayson<br><b>Sent:</b> Monday, April 01, 2013 4:52 PM<br><b>To:</b> LIVE555 Streaming Media - development & use<br><b>Subject:</b> Re: [Live-devel] [PATCH] Provide access to the full time mapping inthe last received sender report<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>The attached patch allows access to the last received sender report RTP timestamp, making it possible to get the full NTP/RTP time mapping currently in effect (since it was already possible to get the last received NTP timestamp).<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>This information can be used to calculate the wallclock timestamp of each sample in a live stream sent by an IP camera, according to the camera’s clock.<o:p></o:p></span></p></div></div></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I think you may not realize that our software already does this automatically! Whenever each frame of data is received (from a "RTPSource" subclass), then the "presentationTime" value will automatically get set to the value calculated from RTCP's 'RTP timestamp-to-NTP' mapping, as long as it has received at least one RTCP "SR" packet.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>In other words, receiving application software should never need to look at RTP timestamps (or RTCP-reported NTP times) directly. Instead, it just needs to look at the "presentation time" values for each received frame.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>For more information see<o:p></o:p></p></div><div><p class=MsoNormal><span class=apple-tab-span> </span><a href="http://www.live555.com/liveMedia/faq.html#separate-rtp-streams">http://www.live555.com/liveMedia/faq.html#separate-rtp-streams</a><o:p></o:p></p></div><div><p class=MsoNormal>and<o:p></o:p></p></div><div><p class=MsoNormal><span class=apple-tab-span> </span><a href="http://www.live555.com/liveMedia/faq.html#rtcp-synchronization-issue">http://www.live555.com/liveMedia/faq.html#rtcp-synchronization-issue</a><o:p></o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>(Therefore, I won't be applying your patch, unless you can demonstrate a clear need for it.)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><span class=apple-style-span><span style='font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black'>Ross Finlayson</span></span><span style='font-size:13.5pt;font-family:"Helvetica","sans-serif";color:black'><br><span class=apple-style-span>Live Networks, Inc.</span><br><span class=apple-style-span><a href="http://www.live555.com/">http://www.live555.com/</a></span></span> <o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>