[mythtv-users] XvMC question

Scott Kidder kidder.scott at gmail.com
Mon Jul 28 18:57:53 UTC 2008


I, too, was having problems with audio stuttering during ATSC playback using
XvMC on both an NVidia 5200 FX and 6200.  The stuttering only occurred when
the OSD was shown: selecting a new channel, and searching forwards or
backwards.  I had been using the AGPGART AGP driver included in the Linux
2.6.xx kernel.

Last weekend I switched to the propritary AGP driver provided by NVidia.
This required adding the 'agp=off' argument to the kernel in the 'grub.conf'
file and re-installing the kernel with grub.  Since then, I've been able to
play ATSC content without XvMC just fine by chosing the 'Normal' or 'High
Quality' playback profiles in the MythTV front-end.  There's a higher load
placed on the CPU (P4 3.0 GHz Hyper-threaded), but it's only around 70% of
an otherwise idle machine.  So, my suggestion might be to try using the
NVidia AGP driver.  More info on configuring the AGP driver is available on
the NVidia site (
http://us.download.nvidia.com/XFree86/Linux-x86_64/169.04/README/chapter-12.html
).

Regards,
Scott Kidder

On Mon, Jul 28, 2008 at 7:21 AM, Allen Edwards <
allen.edwards at oldpaloalto.com> wrote:

> On Sun, Jul 27, 2008 at 11:25 PM,  <ojw at weilerfamily.com> wrote:
> > Quoting Kevin Kuphal <kkuphal at gmail.com>:
> >
> >> On Sat, Jul 26, 2008 at 11:56 PM, <ojw at weilerfamily.com> wrote:
> >>
> >>>
> >>> I'm having what seems to be an XvMC problem.  Perhaps someone
> >>> here can give me a sanity check...
> >>>
> >>> I'm running a P4 1.8Ghz (400Mhz FSB) with 640MB of RAM on a Dell
> >>> Dimension 4400.  I'm using a nvidia 6200 AGP based card (specifically,
> >>> this one:
> >>> http://www.newegg.com/Product/Product.aspx?Item=N82E16814130233)
> >>> I'm recording only mpeg2 streams from an ATSC tuner.  When I try
> >>> to playback 1080i based recordings, I'm averaging in the mid 70%
> >>> range on my cpu meter as reported by top and about every 5 seconds,
> >>> the video stutters.  Based on what I've heard on this list, this
> >>> sounds like this card should be able to offload some of that cpu
> >>> and that maybe I don't have XvMC set up correctly.
> >>>
> >>> I'm pretty sure I followed all the instructions at
> >>> http://www.mythtv.org/wiki/index.php/XvMC.
> >>>
> >>> Here are some of the things I have checked:
> >>>
> >>> "dmesg | grep nvidia" produces this:
> >>>
> >>> nvidia: module license 'NVIDIA' taints kernel.
> >>> NVRM: loading NVIDIA UNIX x86 Kernel Module  173.14.05  Mon May 19
> >>> 00:06:12 PDT 2008
> >>>
> >>> The kernel version is 2.6.25.4 compiled from sources from kernel.org.
> >>>
> >>> "/sbin/lspci | grep -i nvidia" produces:
> >>>
> >>> 01:00.0 VGA compatible controller: nVidia Corporation NV44A [GeForce
> >>> 6200] (rev a1)
> >>>
> >>> "/sbin/lsmod | grep -i nvidia" produces:
> >>>
> >>> nvidia               7091236  36
> >>> i2c_core               20756  12
> >>>
> >>>
> lgdt330x,qt1010,mt2060,mt352,zl10353,xc3028_tuner,tvp5150,tuner,nvidia,em28xx,i2c_i801,tveeprom
> >>>
> >>> The video card section of my xorg.conf looks like this:
> >>>
> >>> Section "Device"
> >>>     Identifier     "Videocard0"
> >>>     Driver         "nvidia"
> >>>     Option         "UseEvents" "true"
> >>>     Option         "XvmcUsesTextures" "false"
> >>>     Option         "NVAGP" "1"
> >>> EndSection
> >>>
> >>> When I do this "grep Motion /var/log/Xorg.0.log", I get this:
> >>>
> >>> (II) Loading extension XVideo-MotionCompensation
> >>>
> >>> Running "mythfrontend --version" produces this:
> >>>
> >>> Please include all output in bug reports.
> >>> MythTV Version   : exported
> >>> MythTV Branch    : tags/release-0-21
> >>> Library API      : 0.21.20080304-1
> >>> Network Protocol : 40
> >>> Options compiled in:
> >>>  linux release using_oss using_alsa using_backend using_dbox2
> >>> using_dvb using_frontend using_hdhomerun using_iptv using_ivtv
> >>> using_joystick_menu using_v4l using_x11 using_xrandr using_xv
> >>> using_xvmc using_xvmcw using_xvmc_vld using_bindings_perl
> >>> using_bindings_python using_opengl using_ffmpeg_threads using_live
> >>>
> >>> I created a playback profile that only uses xvmc.  The
> >>> "playback" setting screen (3 of 9) has only one line that
> >>> looks like this:
> >>>
> >>> if rez > 0 0 -> XvMC
> >>>
> >>> So I'm kinda at a loss.  I'm a newbie to MythTV so feel
> >>> free to point out the obvious.  I'm a competent linux admin
> >>> so if I need to run some more diagnostics from the command
> >>> line, I'd be happy and able to do that.
> >>>
> >>> Any thoughts?
> >>
> >>
> >> Also make sure you have the Composite extension disabled (double check
> the
> >> XvMC page as I'm sure it mentions this)
> >
> > I checked this and I am indeed disabling the Composite extension.  In
> > another post, william_munson at comcast suggested I check the contents
> > of /etc/X11/XvMCconfig to make sure it has one line that says
> > "libXvMCNVIDIA_dynamic.so.1" which it does, though I used a capital C
> > in Config when I created the filename.  Just in case, I made a
> > symbolic link from XvMCconfig to XvMCConfig.  None of that helped.
> >
> > I did a little bit more searching and found that I probably should
> > have built myth with the following config options:
> >
> > --enable-opengl-video --xvmc-lib=XvMCNVIDIA
> >
> > I did that, then remake'd the source and installed and still didn't
> > affect cpu utilization.
> >
> > I suppose now would be a good time to ask:
> >
> > 1.  Did I get the wrong card?
> >
> > 2.  If #1 is no, am I expecting too much out of my poor little old P4
> 1.8Ghz?
> >
> > 3.  Do I need to run nvidia-xconfig or nvidia-settings to help with
> > this situation?
> >
> > 4.  In the XvMC samples page
> > (http://www.mythtv.org/wiki/index.php/XvMC:Example_CPU_Savings), one
> > note said that to get XvMC working, one had to turn on NvAGP.  I'm
> > guessing I have it on based on my settings posted above but how do I
> > know what to set it to or am I barking up the wrong tree?
> >
> > Any other helpful hints to get XvMC working would be greatly appreciated.
> >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >
>
> I could not get acceptable playback with ATSC with my 2.4GHz P4.  It
> would stutter about once every half hour.  My wife couldn't stand it.
> I bought a new AMD 5400+ and it works great.  But, it even it
> stuttered when OSD was on with XvMC so I don't use it.  The install
> instructions encourage no XvMC but with your 1.8G machine, I don't
> think you will get anything to work without it.
>
> Allen
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
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>
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