[mythtv-users] XvMC question

Allen Edwards allen.edwards at oldpaloalto.com
Mon Jul 28 14:21:54 UTC 2008


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.
>
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>

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


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