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</o:shapelayout></xml><![endif]--></head><body lang=DA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Ross<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I have attached a screen dump from WireShark showing you the RTSP protocol exchange between our client and the server (camera).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The “DESCRIBE”, “SETUP” and “PLAY” commands are packet no. 153, 173 and 186.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Venlig hilsen / Best regards<o:p></o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Michael S. Juul<o:p></o:p></span></b></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>B.SC.E.E<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><a href="mailto:mj@unitek.dk"><span lang=EN-US style='color:blue'>mj@unitek.dk</span></a></span><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Unitek A/S</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Vævervej 5</span><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>8800 Viborg</span><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Tlf.: +45 86 61 44 22</span><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><a href="mailto:mail@unitek.dk"><span lang=EN-US style='color:blue'>mail@unitek.dk</span></a></span><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><a href="http://www.unitek.dk/"><span lang=EN-US style='color:blue'>www.unitek.dk</span></a></span><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Fra:</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>På vegne af </b>Ross Finlayson<br><b>Sendt:</b> 11. september 2013 10:54<br><b>Til:</b> LIVE555 Streaming Media - development & use<br><b>Emne:</b> Re: [Live-devel] Presentation time when streaming video recordingfrom surveillance cameras<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 lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We use the RTSPClient from Live555 to access live video and video recordings from surveillance cameras, utilizing the cameras built-in RTSP server and recording storage (An SD card).</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We have a problem regarding the presentation time when streaming video recordings.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Let’s say we have a video recording from “last week” which we would like to stream. We start the stream; we can even start the stream from a specific time in the video recording, so that’s swell.</span><o:p></o:p></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>BUT, the presentation time we receive is “now”, not “last week”.</span><o:p></o:p></p></div></div></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>You're misunderstanding the purpose of "presentation time". The "presentation time" is a timestamp - generated by the server and conveyed to the client for each RTP packet - that tells the client the relative spacing of successive frames of the same media type, and also - if both audio and video substreams are present - allows the client to synchronize the audio and video (i.e., 'lip sync'). The absolute value of the presentation times is undefined and irrelevant. (It is often the 'current' time, but doesn't have to be. E.g., if the server's clock happens to be set to 1990, then the presentation times will be from then.)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>What you want is something like the "normal play time" (NPT), but (as you discovered) we don't compute that when the client is seeking by absolute time, which I think is what you're doing.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>But I think some sort of solution should be possible. To be sure, please give us an example of a RTSP protocol exchange between your client and the server, when you're asking to stream from some time in the past - i.e., the "DESCRIBE", "SETUP", and "PLAY" commands, and their responses.<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><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>