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</o:shapelayout></xml><![endif]--></head><body lang=FR link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Hi Ross,<o:p></o:p></span></p><p class=MsoNormal><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:"Arial","sans-serif";color:#1F497D'>I am afraid that the computation is a bit more complex in the ISO (see <a href="http://www.staroceans.org.s3-website-us-east-1.amazonaws.com/e-book/ISO-14496-10.pdf">http://www.staroceans.org.s3-website-us-east-1.amazonaws.com/e-book/ISO-14496-10.pdf</a>)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Divisor is not always 2, it could be 1, 2, 3,4 or 6.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>For instance, when divisor is 1 live555MediaServer playback a recorded stream twice slower.<o:p></o:p></span></p><p class=MsoNormal><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:"Arial","sans-serif";color:#1F497D'>Just to give a quick answer about VLC, the last time I tried, it still use an default framerate of 25fps and this could be override using –h264-fps argument.<o:p></o:p></span></p><p class=MsoNormal><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:"Arial","sans-serif";color:#1F497D'>Regards,<o:p></o:p></span></p><p class=MsoNormal><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:"Arial","sans-serif";color:#1F497D'> Michel. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>[@@ THALES GROUP INTERNAL @@]<o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","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"'>De :</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> live-devel [mailto:live-devel-bounces@ns.live555.com] <b>De la part de</b> Ross Finlayson<br><b>Envoyé :</b> vendredi 5 décembre 2014 00:33<br><b>À :</b> LIVE555 Streaming Media - development & use<br><b>Objet :</b> Re: [Live-devel] Playback Speed<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";color:#1F497D'>I suppose I could intercept the SPS headers and substitute my own, but looking in the spec, I see no field specifying fps.</span><o:p></o:p></p></div></div></blockquote><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The SPS (optionally) contains "time_scale" and "num_units_in_tick" fields, from which a frame rate can be inferred:<o:p></o:p></p></div><div><p class=MsoNormal><span class=apple-tab-span> </span>frame_rate = time_scale/(2.0*num_units_in_tick)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>FWIW, the LIVE555 code uses this information when it streams (i.e., transmits) H.264 video files. It parses the SPS, trying to find these two fields (and thus the frame rate). If these fields are not present, then our code assumes a frame rate of 25 fps. (If you're interested, you can see this in "liveMedia/H264or5VideoStreamFramer.cpp".)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>VLC presumably does something similar when it tries to play such a file (if it has filename suffix ".h264"). (But this is not a VLC mailing list, so questions about VLC belong elsewhere.)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><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></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>