[mythtv-users] nVidia and XvMC

William Lewis minutemaidpark at hotmail.com
Tue Nov 15 18:27:42 EST 2005


>I have gotten XvMC working on my Athlon 64 with an nVidia 6600LE.
>However, it wasn't easy, basically, I do a brute force hack to beat it
>into submission whenever I start up my X Session.
>
>First, when compiling Myth, force it to compile against libXVMCNVIDIA,
>I've had nothing but trouble with libXVMCW.  This requires modifying the
>"if" statement around line 1699 of configure (talking v0.18.1 here).
>You might need to do "ln
>-s /usr/X11R6/lib/libXvMCNVIDIA.so.1 /usr/lib/libXvMCNVIDIA.so" for this
>to work properly.
>
>Recompile MythTV, go into TV Options and select the option to use XVMC.
>Playback a video and prepare to be disappointed (at least I was).
>
>Why is this?  Because it couldn't open up the video properly.
>Apparently it gets some access denied issue (I'm at work so I can't get
>the exact output right now).  Here's what I did to fix it.
>
>Create a two frame mpeg movie using mencoder.  It's important that it
>have more than one frame.  Two seems to work quite well.  Then, I made
>sure that my version of mplayer had xvmc support with it.  I had to
>recompile it for that (using Ubuntu Breezy).  Then, I had my startup
>script for mythfrontend execute the following script:
>
>#!/bin/sh
># bang away on XVMC until it works
>ROUNDS=0
>for x in $(seq 1 100); do
>         LINE=$(~/bin/mplayer -vo xvmc -vc ffmpeg12mc ~/bin/fix.mpg -ao 
>none 2>&1 | grep "End of file")
>         if [ "x$LINE" == "xExiting... (End of file)" ]; then
>                 echo "Took ${ROUNDS} tries to succeed"
>                 exit
>         fi
>         ROUNDS=$x
>done
>echo "Unable to initialize xvmc"
>
>Where fix.mpg is the name my little two frame mpeg file.  This
>essentially tries to run Mplayer 100 times on the little file.  The
>first time it actually succeeds and plays it, it stops.  The reason is
>because I notice that once I actually had XVMC working, it would just
>keep working for that session.  Thus, by beating XVMC into submission
>when I first start, I'm good for XvMC on MythTV.  Usually it takes about
>3 or 4 tries.  Once it took 15, but that's the most.  This script
>automates all that, and makes it transparent.
>
>That being said, XVMC is not a be all end all here.  It still seems far
>from perfect.  Occassionally I see a frame that looks out of place, I've
>been told that this is a sign that XVMC isn't working 100% properly on
>my system [1].  But XVMC is working.  I now have a grayscale display
>that gets really choppy when the UI is up, but requires basically 0
>overhead on my XOrg server instance.
>
>This is good enough for me to watch and pause live 720p programs with no
>difficulty.  Overall CPU load will hover around 20% there with
>ocassional I/O related hiccups.  However, I still have some problems
>with 1080i programs stuttering, probably I/O related issues.  I think
>there is something funky with my motherboard and linux support (I get
>the nasty digital static on my pcHDTV card too, but HDTV from the cable
>box works fine).  So, if anyone knows ways to make those better, I'd
>love to hear them.  Otherwise I'm gonna have to buy a new motherboard,
>which is a shame because this one has gazillions of bells and
>whistles(the pcHDTV records just fine on my Athlon 700, that just can't
>play it back).
>
>FWIW, here's the specs on the system I'm working with:
>AMD 3200+ (clocked at 2400), 1GB generic ram, MSI k8n-neo4 platinum,
>400GB LVM DMA 100/133 drives (2 x 200, hdparm -tT gives a read rate of
>about 50MB/s on the drive), WinTV PVR-250, XFX GeForce 6600LE 256MB,
>firewire to DCT6200 comcast box, pcHDTV 3000 (which gets staticy if
>there is any other substantial disk I/O at the same time, don't blame
>the OC either, it barfs at 2GHz too).
>
>--Patrick
>
>[1] http://gentoo-wiki.com/HOWTO_Setup_MythTV
>


>_______________________________________________
>mythtv-users mailing list
>mythtv-users at mythtv.org
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users


Well, I just got home, recompiled mplayer (with xvmc support this time 
(Oops)), and everything worked like a charm.  Great picture, no breaks, 18% 
CPU usage while watching recorded video.  What a difference.  Thanks for all 
your help.




More information about the mythtv-users mailing list