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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">First of all, thank you for the reply. Please see my comments embedded in the email below.<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 style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Best Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Sarma Kolavasi<o:p></o:p></span></p>
<p class="MsoPlainText">UTC Building and Industrial Systems,<o:p></o:p></p>
<p class="MsoPlainText">8310 Capital of TX Hwy N<o:p></o:p></p>
<p class="MsoPlainText">Austin, TX 78731<o:p></o:p></p>
<p class="MsoPlainText">(W) 512.527.5932<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<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 [mailto:live-devel-bounces@ns.live555.com]
<b>On Behalf Of </b>Ross Finlayson<br>
<b>Sent:</b> Saturday, May 30, 2015 1:39 PM<br>
<b>To:</b> LIVE555 Streaming Media - development & use<br>
<b>Subject:</b> [External] Re: [Live-devel] Support for 'Speed" Option on RTSP 'PLAY'<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sarma,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>Thanks for the note. I’d be happy to add support in “RTSPClient” for the<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">></span>”Speed:” parameter (as it’s part of the RTSP standard (albeit rarely used)).
<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>However, I have some comments/questions about the mechanism that you’re using:<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">[SK] 'Speed' is an important requirement for video surveillance system where post motion search and rendering of content in time-lapsed mode require faster download.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">></span>1/ Remember to upgrade to the latest version of the code (I see that you’re using a version from 2014).<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span> There have been several improvements and bug fixes (including to “RTSPClient”) since then.<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">[SK] Yes, we currently use Live555 version, “2014.10.07”. And it passed our system test with no known issues. I plan to upgrade Live555 in our next release. If support for 'Speed()' is available, then that would
be even be better.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">></span>2/ You don’t need “setSpeed()” functions in “MediaSession” or “MediaSubsession”,<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>because the “speed()” function returns a “float&”. I.e., your calling code could just do (e.g.)<o:p></o:p></p>
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<p class="MsoNormal"><span class="apple-tab-span"><span style="color:#1F497D">></span></span><span class="apple-tab-span">
</span>session<-speed() = 2.0;<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>instead of<o:p></o:p></p>
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<p class="MsoNormal"><span class="apple-tab-span"><span style="color:#1F497D">></span></span><span class="apple-tab-span">
</span>session<->setSpeed(2.0);<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">[SK] Thanks for the suggestion.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">></span>3/ I don’t see where - in “RTSPClient” - you’re ever setting the ‘speed’ value<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>(that your code checks to determine whether or not it needs to include a<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>“Speed:” parameter in the “PLAY” request. Presumably you need<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>some function in the “RTSPClient” API that allows calling code<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>to set that value. I wouldn’t want to add this parameter to the<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>(already crowded) “RTSPClient::sendPlayCommand()” function,<span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">></span>because it’s going to be so rarely used. Instead, you could add a function like<o:p></o:p></p>
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<p class="MsoNormal"><span class="apple-tab-span"><span style="color:#1F497D">></span></span><span class="apple-tab-span">
</span>void RTSPClient::setSpeed(MediaSession& session, float speed = 1.0);<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>that would set the ‘speed’ parameter to be used in subsequent “PLAY” commands.<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">></span>How were you intending to set this value?<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D">[SK] In my case, setSpeed() is called directly from the adapter code (module included in the zip file attached to initial email),<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">postDescribe(), RTSPAsyncAdapter.cpp, line 127, and<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">setupNextSubsession(), RTSPAsyncAdapter.cpp, line 158 for MediaSession and MediaSubsession respectively.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I coded this way for two reasons:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="color:#1F497D"><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Thought, it was simple to call setSpeed() right after a MediaSession and MediaSubsession were instantiated.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo1"><![if !supportLists]><span style="color:#1F497D"><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">I was trying to minimize changes to the Live555 core modules.<o:p></o:p></span></p>
<p class="MsoListParagraph"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Your suggestion to add new API, RTSPClient::setSpeed(), makes sense.
<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>
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<p class="MsoNormal"><span class="apple-style-span"><span style="font-family:"Helvetica","sans-serif";color:black">Ross Finlayson</span></span><span style="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>
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