[mythtv-users] xorg.conf Section Extension

[Drew Tomlinson]

I'm attempting to enable XvMC on a Nvidia FX 5500 card.  I've followed 
the instructions on the wiki 
(http://mythtv.org/wiki/index.php/XvMC#NVIDIA_2).  My question is 
regarding adding these lines to my xorg.conf file:

Section "Extensions"
    Option "Composite" "Disabled"
EndSection

What do these lines mean?  "Section Extensions" is not in the xorg.conf 
man page.  Googling reveals lots of advice to *enable* it for Compiz but 
no explanation of what it does.

My experience is that when this section is in my xorg.conf, chromakey 
works.  With chromakey working, I don't get nearly as much audio stutter 
when the OSD is on.  Also, the picture looks like it has been 
deinterlaced.  However the Off | Half | Full | Stretch view modes do not 
work properly.  Left and right cropping is OK but vertical cropping is 
only cropped from the top.  The bottom is not cropped.  This feature is 
important to me because I have a widescreen television and use the Full 
mode when viewing letterboxed content.  I hate watching a small picture 
in the middle of my screen.  ;)

When this section is not in my xorg.conf file, chromakey doesn't work as 
evidenced by this snippet of my frontend log:

2008-05-06 11:15:18.338 VideoOutputXv: XvMC Adaptor Name: 'NV17 Video 
Texture'
2008-05-06 11:15:18.388 VideoOutputXv: Ack! Disabling ChromaKey OSD
                        We can't use ChromaKey OSD if chromakeying is 
not supported!

Thus the audio is very choppy anytime the OSD is displayed.  However the 
Off | Half | Full | Stretch view mode work just fine.

Is there anyway I can have both chromakey and proper cropping?  I've 
included my xorg.conf for the nvidia 169.12 drivers below.

Thanks,

Drew

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 1.0  (buildmeister at builder3)  Thu Feb 14 
18:20:37 PST 2008

# 05/05/08
# Upgraded from MX 4000 card to FX 5500 card in an effort to get XvMC 
working.
# Old card was not supported by the v100+ drivers.  New card worked OK 
with old
# drivers but upgraded to newest to see if there was any improvement (not
# really).  After upgrade, XvMC would just max out CPU usage my mythfrontend
# and result in black screen.  Started over with brand new config generated
# by nvidia-xconfig.  Added old modeline (wouldn't work with "auto") and 
a few
# other bits.  Seems to be working OK.  Minor audio stutter occasionally.

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
    RgbPath         "/usr/lib/X11/rgb"
EndSection

Section "Module"
    Load           "dbe"
    Load           "extmod"
    Load           "type1"
    Load           "freetype"
    Load           "glx"
EndSection

Section "InputDevice"
    # generated from data in "/etc/conf.d/gpm"
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol"
    Option         "Device" "/dev/input/mice"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       30.0 - 110.0
    VertRefresh     50.0 - 150.0
    Option         "DPMS"
    DisplaySize       447 251
    # My 1920x1080i mode
    Mode "1920x1080i"
         DotClock 74.25
         HTimings 1760 1928 1984 2204
         VTimings 990 1034 1040 1113
         Flags "-HSync" "-VSync" "Interlace"
    EndMode
EndSection

Section "Device"
        Identifier  "Device0"
        Driver      "nvidia"
        VendorName  "eVGA"
        BoardName   "NV34 GeForce FX 5500"
        Option      "NvAGP" "1"
    Option         "RenderAccel" "TRUE"
    Option      "XvmcUsesTextures" "FALSE"
    Option      "UseEvents" "true"
        Option      "NoLogo" "1"
        Option      "ConnectedMonitor" "CRT"
        Option      "UseEdid"   "FALSE"
    Option      "AllowGLXWithComposite" "true"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
        Modes "1920x1080i"
    EndSubSection
EndSection

Section "DRI"
#        Group        0
        Mode         0666
EndSection

# This section breaks Zoom mode in Myth. No cropping done from bottom. All
# from top.  However this section is required for chromakey OSD to work.
#
#Section "Extensions"
#        Option "Composite" "Disabled"
#EndSection

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