Terry Barnaby wrote: > Hi, > > I am trying to track down a problem I have with MythTv under Fedora 8 using > the openchrome driver and libchromeXvMC library. > MythTv has a lot of juddering and glitches even though the XvMC VLD > acceleration is in use. > This is also present with the stock via driver and libviaXvMC library. > > Using the old mp2decoder XvMC test program I see that sending one > frame at 25Hz uses about 12% CPU. If I modify mp2decoder to send > two frames at 50Hz (Just calling XvMCPutSurface twice with the same > frame) the CPU usage shoots up to 98%. This is equivalent to > MythTv outputting in BOB de-interlace mode and appears to show the > same problem I have with MythTv. > > I guess this could be a libchromeXvMC/libviaXvMC or DRM issue. > Has anyone any idaes on this ? > > Cheers > > > Terry > > > _______________________________________________ > openchrome-users mailing list > [email protected] > http://wiki.openchrome.org/mailman/listinfo/openchrome-users > Main page: > http://www.openchrome.org > Wiki: > http://wiki.openchrome.org > User Forum: > http://wiki.openchrome.org/tikiwiki/tiki-view_forum.php?forumId=1 >
I have tracked this down a bit further. The syncVideo() routine is being called from pciFlush() with doSleep = 0. This is sitting in a tight loop for 20ms (I guess until the next VSYNC ??). Even setting doSleep to 1 does not fix the issue as in MythTv the output thread is a Realtime thread and nanosleep() is, I believe, implemented as a tight loop when call from a real-time thread. I'm not sure of exactly the best way to fix this issue ... Does syncVideo() wait for the next VSYNC period ? Cheers Terry _______________________________________________ openchrome-users mailing list [email protected] http://wiki.openchrome.org/mailman/listinfo/openchrome-users Main page: http://www.openchrome.org Wiki: http://wiki.openchrome.org User Forum: http://wiki.openchrome.org/tikiwiki/tiki-view_forum.php?forumId=1
