I've recently installed Mythbuntu 10.10 on an Epia M10000 to make a combined front and backend system. I have managed to get the S-Video output working without tearing, using quite low CPU usage and realtime priority during playback. However, sometimes there are glitches in the output, and associated prebuffering pause messages in mythfrontend.log.<br>
<br>I've looked through the relevant page of possible causes on the wiki, but am still not quite sure how to pinpoint the cause in my case.<br><br>Firstly, I disabled CPU frequency scaling by setting scaling_min_freq to the maximum for my processor (997000). This change didn't seem to notably reduce the problem, <br>
<br>In a log including playback messages I've noticed that approximately half a second after each xscreensaver-command entry, at least one prebuffering pause would occur. eg:<br><br>2010-10-25 21:56:44.202 ScreenSaverX11Private: Calling xscreensaver-command -deactivate<br>
2010-10-25 21:56:44.611 NVP(0): prebuffering pause<br>2010-10-25 21:56:44.613 NVP(0): Waiting for prebuffer.. 0 AAUAAAAAALAdLAA<br>2010-10-25 21:56:44.708 NVP(0): prebuffering pause<br>2010-10-25 21:56:44.709 NVP(0): Waiting for prebuffer.. 0 AADAALAAALADUAA<br>
<br>This isn't the only time that prebuffering pauses occur, but it accounts for the majority and so I would like to establish why these ones are occurring first.<br><br>With frequency scaling disabled (as described above) and watching live TV, top tends to show between 55% and 70% idle. When the xscreensaver-command occurs I don't always see idle drop to 0%, but wonder if this is due to the refresh rate of top. Therefore, I'm not sure if CPU bottleneck might be causing the problem.<br>
<br>I don't think swap is an issue because I've 1GB RAM, and top indicates only about 20MB of swap is used.<br><br>I do wonder if the hard drive might be a potential culprit - I'm using a 1TB WD10EARS partitioned with a system partition (ext3), swap and data (xfs). This is a sata drive, so I've got a sata<->IDE converter. Is there a way for me to check the drive performance? Alternatively is it possible to get MythFrontend to buffer more data from disk, so it can cope with longer interruptions in the data?<br>
<br>If I've missed any important information then just let me know.<br><br>Any help would be greatly appreciated.<br><br>Thanks,<br>Rob<br><div style="visibility: hidden; left: -5000px;" id="avg_ls_inline_popup"></div>
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