[mythtv-users] Digital Pegs CPU

Paulin paulin at spextreme.com
Wed Nov 26 22:01:15 UTC 2008


On Wed, Nov 26, 2008 at 1:33 AM, Rod Smith <mythtv at rodsbooks.com> wrote:

> On Tuesday 25 November 2008 08:24:01 pm Paulin wrote:
> > Myth Community,
> > I'm hoping someone can point me in the right direction on this one.
> >
> > I currently have a VIA EPIA M10000 (1ghz processor) with 512 RAM running
> > MiniMyth.  When I run an analog program (recorded or live) from the
> backend
> > it looks pretty good.  The CPU is running around 70%.  However when I run
> a
> > Digital signal (live or recorded) the picture pauses regularly (about
> every
> > 30 seconds), kinda like a buffer playing catchup.  Anyway I've noticed
> the
> > CPU is pegged at 100% so I believe that is really the issue for the
> > stuttering.
>
> I think you need to be more precise concerning your recording
> types/formats.
> To MythTV, all recordings are digital, so there's something other than this
> that differentiates your recordings. (I know you mean analog transmission
> vs.
> digital transmission [or perhaps some other medium, like DVDs], but my
> point
> is that a factor that happens to be correlated with this distinction is the
> real culprit, not the analog vs. digital source per se.) There's a good
> chance that your recordings vary in their resolutions and/or bitrates. This
> is particularly true if your "digital" signal is in fact an HDTV broadcast.
> My suspicion is that an HD recording will strain a 1GHz CPU; depending on
> the
> precise format and various other options, such recordings can consume half
> or
> more of my 3GHz Intel Celeron-D CPU's time. Issues like recording format
> (MPEG-2 vs. MPEG-4 vs. other odd formats) can also play a role.
>
> One factor that I found extremely important is proper X configuration.
> Specifically, with an nVidia video card, be sure the following line appears
> in the "Device" section for your video card in /etc/X11/xorg.conf:
>
>    Option         "UseEvents" "True"
>
> Without this line, X uses excessive CPU time, thus producing stuttering and
> other problems when playing back HD recordings on my system. It's
> conceivable
> you'd see similar symptoms even with SD content on a 1GHz system if this
> isn't set correctly.
>
> There are lots of other potential culprits, too, like deinterlacing
> settings,
> XvMC support, etc.
>
> --
> Rod Smith
> _______________________________________________
>

Well I did have the UseEvents option in the xorg.conf.  Here is my xorg in
case you see any other issues.

Section "Files"

#    ModulePath  "/usr/lib/nvidia/xorg/modules"

    ModulePath  "/usr/lib/xorg/modules"

EndSection


Section "ServerFlags"

    Option      "DefaultServerLayout" "Layout1"

    Option      "XkbDisable"          "false"

    Option      "AllowMouseOpenFail"  "true"

    Option      "BlankTime"           "0"

    Option      "StandbyTime"         "0"

    Option      "SuspendTime"         "0"

    Option      "OffTime"             "0"

    Option      "NoPM"                "true"

    Option      "Xinerama"            "false"

    Option      "AIGLX"               "false"

EndSection


Section "Module"

    Load        "dbe"

    Load        "dri"

    Load "extmod"

    Load        "freetype"

    Load "glx"

    Load        "int10"

    Load        "record"

EndSection


Section "InputDevice"

    Identifier "Keyboard1"

    Driver "kbd"

    Option      "AutoRepeat"   "500 30"

    Option      "XkbRules"     "base"

    Option      "XkbModel"     "pc105"

    Option      "XkbLayout"    "us"

EndSection


Section "InputDevice"

    Identifier "Mouse1"

    Driver      "mouse"

    Option      "Protocol"     "PS/2"

    Option      "Device"       "/dev/input/mice"

    Option      "ZAxisMapping" "4 5"

EndSection


Section "Monitor"

    Identifier  "Monitor1"

    DisplaySize 320 180

    HorizSync 10.0-70.0

    VertRefresh 58.0-62.0,118.0-122.0









EndSection


Section "Device"

    Identifier  "Device_intel_810"

    Driver      "intel"

    Option      "XvMCSurfaces"    "7"

    Option      "XvPreferOverlay" "true"


    Option      "Monitor-" "Monitor1"

EndSection


Section "Device"

    Identifier  "Device_intel_915"

    Driver      "intel"

    Option      "XvPreferOverlay" "true"


    Option      "Monitor-" "Monitor1"

EndSection


Section "Device"

    Identifier  "Device_nvidia"

    Driver      "nvidia"

    Option      "NoLogo"              "true"

    Option      "ConnectedMonitor"    ""

    Option      "TVStandard"          "NTSC"

    Option "TVOutFormat"         "S-Video"

    Option "TVOverScan"          "0.0"

    Option      "UseEdidFreqs"        "false"

    Option      "UseEDIDDpi"          "false"

    Option      "DynamicTwinView"     "false"

    Option      "UseEvents"           "true"

    Option      "ExactModeTimingsDVI" "true"

    Option      "ModeValidation"      "NoDFPNativeResolutionCheck"

EndSection


Section "Device"

    Identifier  "Device_openchrome"

    Driver      "openchrome"

    Option      "EnableAGPDMA"        "true"

    Option      "ActiveDevice"        "TV"

    Option "TVType"              "NTSC"

    Option "TVOutput"            "S-Video"

    Option      "TVDeflicker"         "2"

EndSection


Section "Device"

    Identifier  "Device_radeon"

    Driver      "radeon"

EndSection


Section "Device"

    Identifier  "Device_radeonhd"

    Driver      "radeonhd"

EndSection


Section "Device"

    Identifier  "Device_savage"

    Driver      "savage"

EndSection


Section "Device"

    Identifier  "Device_sis"

    Driver      "sis"

EndSection


Section "Device"

    Identifier  "Device_vmware"

    Driver      "vmware"

EndSection


Section "Screen"

    Identifier  "Screen1"

    Device      "Device_openchrome"

    Monitor     "Monitor1"

    DefaultDepth 24


    Subsection "Display"

        Depth       24

        ViewPort    0 0

        Modes       "704x480" "704x480" "704x480" "704x480"

    EndSubsection

EndSection


Section "ServerLayout"

    Identifier  "Layout1"

    Screen      "Screen1"

    InputDevice "Mouse1"       "CorePointer"

    InputDevice "Keyboard1"    "CoreKeyboard"

EndSection


Section "DRI"

    Mode 0666

EndSection



And I'm sorry if I'm not explaining things properly.  A lot of this is very
new to me and I'm still trying to learn.

As for my Digital/Analog.  Basically I have Comcast who is sending the
analog and digital over the line.  I have two cards.  The PVR250 recording
the analog channels from Comcast.  Then I have a HVR1250 getting the Comcast
digital channels.   I did realize they are all become MPEG files and I would
guess the digital is MPEG4 while the PVR is doing MPEG2 (but that is a
guess).

I figured the digital recordings are just bigger (bit rate/resolution) which
is accounting for the problem.  So with that how can I adjust that.  Second
I know that the M10000 board has an MPEG decoder, so I'm surprised the CPU
is hit as much for playback.  Or is it being hit for the data transmission
(streaming) that is causing the problem.

And again I'm sorry if I'm using the wrong terms or not describing things
well.  Still learning.

Thanks
steve
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