<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On 30/08/2008, at 10:08 PM, Robert Longbottom wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>Kingsley Turner wrote:<br><blockquote type="cite">Hi,<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I'm getting "pre-buffering" pauses playing live-tv. I know this because <br></blockquote><blockquote type="cite">it's in the mythfrontend logfile.<br></blockquote><blockquote type="cite">What does this actually mean? What's it waiting on? Reading from the <br></blockquote><blockquote type="cite">tv-card?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">BBC HD works ok, but Swiss HD has 1/2 second pauses every few seconds <br></blockquote><blockquote type="cite">when there's high motion displayed (I assume the greatest bitrate),<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The video signal is a 1280x720 50Hz h264 stream, running at around <br></blockquote><blockquote type="cite">10kbit (or is this mbit?) according to VLC.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I can playback the recorded HD stream OK though, it's only live TV that <br></blockquote><blockquote type="cite">stutters.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">I disabled all non-used devices in the BIOS.<br></blockquote><blockquote type="cite">I turned off OpenGL synch<br></blockquote><blockquote type="cite">I set both RTC and HPET to 1024 in /etc/sysctl.conf<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">This is a dual-core (10 week old) core2-duo (<a href="mailto:E7200@2.53GHz">E7200@2.53GHz</a>) with 2G ram, <br></blockquote><blockquote type="cite">SATA2 disk. CPU use during playback is around 80-105% So it's using <br></blockquote><blockquote type="cite">about 1/2 it's processing power.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">The video-playback configuration is set to use "linear-blend' <br></blockquote><blockquote type="cite">deinterlacer, with a fallback of "none".<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">It drawing to an onboard nvidia 7100, but i just tried a separate <br></blockquote><blockquote type="cite">pci-x-16 8600GT with absolutely no change in symptoms.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Does commercial flagging run during live TV? Or is this only <br></blockquote><blockquote type="cite">post-processing for recorded shows?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Would throwing more hardware at this help? <br></blockquote><blockquote type="cite">1066MHz ram instead of 800?<br></blockquote><blockquote type="cite">Quad core CPU ?<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">Although it doesn't seem to be CPU bound ... but before the tuning CPU <br></blockquote><blockquote type="cite">was getting up to 180% (i.e.: almost maxing out both cores)<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">any hints ?<br></blockquote><br>Sounds like you've already checked a lot of things, but you don't say if <br>you've set the "number of CPU's" in Playback settings.... I think it's <br>set to 1 by default - you should have changed it to 2.<br><br> From what you've said the hardware you've got should be more than <br>enough to playback HD, so it must be configuration somewhere.<br><br></div></blockquote><br></div><div>The hardware is fast enough for MPEG-2 HD, but H.264 is a different game altogether.</div><div><br></div><div>If you are hitting 180% during live TV there is a chance that during peaks in CPU load the myth backend is struggling to get the inbound signal onto the disk, and back to the frontend.</div><div><br></div><div>Here in NZ we have similar issues with a local 1080i stream that required more CPU than most of us have at present. You might want to take a look at some NZ specific patches that tweak some of the H.264 settings to give slghtly better performance.</div><div><br></div><div>Steve</div><div><br></div><div><br></div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Steven Ellis - Technical Director<br>OpenMedia Limited<br>email - <a href="mailto:steven@openmedia.co.nz">steven@openmedia.co.nz</a><br>website - <a href="http://www.openmedia.co.nz/">http://www.openmedia.co.nz</a><br></div></div></span> </div><br></body></html>