XOrg Configuration

xorg.conf

 Section "Monitor"
        Identifier      "SD TV"
        VendorName      "TV Vendor"
        ModelName       "TV Model"
        HorizSync       15.625 #kHz
        VertRefresh     50.0 #Hz 
        DisplaySize     400 225
 EndSection

Section "Monitor" Options useful to MythTV

DisplaySize 

This allows you to set the aspect ratio of your TV. 400 225 is 16:9 400 300 is 4:3

Nvidia

 Section "Device"
        Identifier      "GeForce 8500 GT 256MB"
        Driver          "nvidia"
        VendorName      "Asus"
        BoardName       "Nvidia GeForce 8500 GT"
        BusID           "PCI:5:0:0"
        Option  "NoLogo"                "True"
        Option  "RenderAccel"           "True"
        Option  "XvmcUsesTextures"      "True"
        Option  "UseEdidDpi"            "False"
        Option  "DPI"                   "100 x 100"
        Option  "UseEvents"             "False"
        Option  "DPMS"                  "False"
 EndSection

Section "Device" Options useful to MythTV

Option "DPI" 

This allows you to set the font DPI and will override any other places it is set (Apart from EDI) . Myth is set to look best when your fonts have a DPI of 100x100.

Option "DPMS" 

Setting this to "False" turns off 'Display Power Management Signaling' for your monitor or TV (Meaning your screen won't blank after 20 mins). However I'm not sure if it is necessary to set this any longer as I believe Myth manages it for you.

Option "NoLogo" 

Setting this to "True" turns off the Nvidia logo when X starts.

Option "RenderAccel" 

Option "UseEdidDpi" 

Setting this to "False" will stop the Nvidia drivers from reading your TV/Monitors EDI and therefore overriding your "DPI" setting.

Option "UseEvents" 

Option "XvmcUsesTextures" 

 Section "Screen"
        Identifier      "Screen0"
        Device          "GeForce 8500 GT 256MB"
        Monitor         "SD TV"
        Option          "TVStandard"            "PAL-I"
        Option          "UseDisplayDevice"      "TV"
        Option          "TVOutFormat"           "SVIDEO"
        Option          "TVOverScan"            "0.0"
        DefaultDepth    24
 EndSection

Section "Screen" Options useful to MythTV

Option "TVOutFormat" 

Tell the Nvidia drivers how they output to your display device. Options are; AUTOSELECT, COMPONENT, COMPOSITE, SCART, SVIDEO

To use COMPOSITE you will need to use the s-video to rgb cable and use the blue connector. The COMPOSITE signal will be on there.

Option "TVOverScan" 

Can be used to enable Overscan, when the TV encoder supports it. Valid values are decimal values in the range 1.0 (which means overscan as much as possible: make the image as large as possible) and 0.0 (which means disable overscanning: make the image as small as possible). Overscanning is disabled (0.0) by default.

Option "TVStandard" 

Used to set the TV out resolution. Options are; PAL-B, PAL-D, PAL-G, PAL-H, PAL-I, PAL-K1, PAL-M, PAL-N, PAL-NC, NTSC-J, NTSC-M, HD480i, HD480p, HD720p, HD1080i, HD1080p, HD576i, HD576p

Option "UseDisplayDevice" 

The "UseDisplayDevice" option can be used if there are multiple display devices connected, and you want the connected TV to be used instead of the connected CRTs and/or DFPs.

XvMC config

Nvidia

If XvMC does not seem to be working with the nvidia binary drivers installed or X is consuming a lot of cpu while using XvMC output in Myth, look for the file XvMCConfig in your /etc/X11 directory. the contents of the file should point to libXvMCNVIDIA_dynamic.so.1 on your system. After a fresh Gentoo build and emerge of .20 mythtv this file did not exist, so i coppied it over from my knoppmyth build and edited it to suit my system. Cpu usage dropped in half and XvMC started working as evidenced by the colorless osd!

/usr/lib/libXvMCNVIDIA_dynamic.so.1

VGA to SCART converter

The 'TV out' on most graphics cards produces a less than acceptable picture and has 'hardware locked' resolutions/refresh rates. Using the VGA (RGB) out allows you to have total control.

This method will achieve, by far, the best result when outputting to a SD TV. The picture quality will be equal or better than that of a digibox and motion problems (unsmooth news tickers & camera 'pans') linked with resolution and refresh rates can be fine tuned with modelines. You will need to have an RGB capable SCART input on your TV.

Modelines

To get fine control over the resolution and be able to use a VGA to SCART converter you need to use modelines. Modelines go in the 'Monitor' section and are then referenced in the 'Screen' section of your xorg.conf eg.

Section "Monitor"
        Identifier      "SD TV"
        VendorName      "Monitor Vendor"
        ModelName       "Monitor Model"
        HorizSync       14 - 18.0 #kHz
        VertRefresh     45 - 65.0 #Hz
        
        ## 720x576 @ 25Hz, 15.6kHz hsync, ccir601 PAL, mpeg, 702 dots displayed
        ModeLine "720x576@25i" 13.5   720 732 795 864  576 581 586 625 interlace -hsync -vsync

        ## Set for 16:9 display. For 4:3 replace 225 with 300.
        DisplaySize     400 225
EndSection

...

Section "Screen"
        Identifier      "Screen0"
        Device          "GeForce 8500 GT 256MB"
        Monitor         "SD TV"
        SubSection      "Display"
                Modes   "702x576@25i" "704x576@25i" "720x576@25i" "768x576@25i" "768x576@50" "720x576@60" "720x576i"
                Depth   24
        EndSubSection
EndSection

Here are some other PAL modelines that may be helpful

• Mode lines for SD PAL TV resolutions

       Modeline "800x576pali" 15.38  800 823 895 984  576 580 583 625 -hsync -vsync interlace
       Modeline "800x288pal-half"  15.38  800 823 895 984  288 290 292 313 -hsync -vsync
       Modeline "768x576pali" 14.76  768 789 858 944  576 580 583 625 -hsync -vsync interlace
       Modeline "768x288pal-half"  14.76  768 789 858 944  288 290 292 313 -hsync -vsync
       Modeline "720x576pali" 13.88  720 742 808 888  576 580 583 625 -hsync -vsync interlace
       Modeline "720x288pal-half"  13.88  720 742 808 888  288 290 292 313 -hsync -vsync
       Modeline "704x576pali" 13.50  704 722 786 864  576 580 583 625 -hsync -vsync interlace
       Modeline "704x288pal-half"  13.50  704 722 786 864  288 290 292 313 -hsync -vsync
       Modeline "650x576pali" 12.50  650 669 728 800  576 580 583 625 -hsync -vsync interlace

• Some others

1. ## 702x576 @ 25Hz, 15.6kHz hsync, itu-r bt.470 PAL, analog broadcast

ModeLine "702x576@25i" 13.5 702 722 785 864 576 581 586 625 interlace -hsync -vsync

1. ## 704x576 @ 25Hz, 15.6kHz hsync, itu-r bt.470 PAL, mpeg, 702 dots displayed

ModeLine "704x576@25i" 13.5 704 723 786 864 576 581 586 625 interlace -hsync -vsync

1. ## 720x576 @ 25Hz, 15.6kHz hsync, ccir601 PAL, mpeg, 702 dots displayed

ModeLine "720x576@25i" 13.5 720 732 795 864 576 581 586 625 interlace -hsync -vsync

1. ## 768x576 @ 25Hz, 15.6kHz hsync, square dot itu-r bt.470 PAL, TV-monitor, 767 dots displayed

ModeLine "768x576@25i" 14.75 768 789 858 944 576 581 586 625 interlace -hsync -vsync

1. ## 768x576 @ 50Hz, 31.3kHz hsync, progressive square dot itu-r bt.470 PAL

ModeLine "768x576@50" 29.5 768 789 858 944 576 581 586 625 -hsync -vsync

1. ## nonstandard PAL (Works with BOB deinterlace) It is 60Hz but works well with nVIDIA PAL-B TV-OUT Nvidia option: Option "TVStandard" "PAL-B"

ModeLine "720x576@60" 32.7 720 744 816 912 576 577 580 597

1. ## This modeline is 50Hz interlaced and works well with kerneldeint:

ModeLine "720x576i" 13.875 720 744 808 888 576 581 586 625 -hsync -vsync interlace

And some NTSC ones

• Mode lines for SD NTSC TV resolutions

       Modeline "800x480ntsci" 15.10  800 808 879 960  480 484 487 525 -hsync -vsync interlace
       Modeline "800x240ntsc-half"  15.10  800 808 879 960  240 242 244 263 -hsync -vsync
       Modeline "720x480ntsci" 13.59  720 727 791 864  480 484 487 525 -hsync -vsync interlace
       Modeline "720x240ntsc-half"  13.59  720 727 791 864  240 242 244 263 -hsync -vsync
       Modeline "704x480ntsci" 13.34  704 714 776 848  480 484 487 525 -hsync -vsync interlace
       Modeline "704x240ntsc-half"  13.34  704 714 776 848  240 242 244 263 -hsync -vsync
       Modeline "657x480ntsci" 12.50  657 667 725 792  480 484 487 525 -hsync -vsync interlace
       Modeline "657x240ntsc-half"  12.50  657 667 725 792  240 242 244 263 -hsync -vsync
       Modeline "640x480ntsci" 11.32  640 646 703 786  480 484 487 525 -hsync -vsync interlace
       Modeline "640x240ntsc-half"  11.32  640 646 703 786  240 242 244 263 -hsync -vsync

Nvidia Configuration

Section "Device"
        Identifier      "GeForce 8500 GT 256MB"
        Driver          "nvidia"
        VendorName      "Asus"
        BoardName       "Nvidia GeForce 8500 GT"
        BusID           "PCI:5:0:0"
        Option  "UseEDIDFreqs"          "False"
        Option  "UseEdidDpi"            "False"
        Option  "ModeValidation"        "AllowNon60HzDFPModes, NoMaxPClkCheck, NoEdidMaxPClkCheck, AllowInterlacedModes, NoMaxSizeCheck, NoHorizSyncCheck, NoVertRefreshCheck, NoWidthAlignmentCheck, NoDFPNativeResolutionCheck, NoVirtualSizeCheck, NoVesaModes, NoEdidModes, NoXServerModes, NoPredefinedModes" 
        Option  "NoLogo"                "True"
        Option  "XvmcUsesTextures"      "True"
        Option  "DPI"                   "100 x 100"
        Option  "UseEvents"             "False"
        Option  "DPMS"                  "False"
EndSection

Building a VGA to SCART converter

Before we start I must credit these two pages, most of this information came from these sources:

http://www.idiots.org.uk/vga_rgb_scart/index.html http://www.nexusuk.org/projects/vga2scart/circuit

Materials (aside from leads):

• 3.3K Ohm Resistor - (R1) - (Farnell order No. 934-3040)
• 1.2K Ohm Resistor - (R2) - (Farnell order No. 934-2524)
• 820 Ohm Resistor - (R3) - (Farnell order No. 934-3563)
• 68 Ohm Resistor - (R4) - (Farnell order No. 934-3490)
• BC548B Transistor - (Q1) - (Farnell order No. 933-910)

The easiest way to do this is to buy a VGA monitor extender lead (just male to male) and a SCART lead that has one of the plastic case connectors you can open. Cut one end off the VGA lead, open and unsolder the SCART connector then solder it to the VGA lead as follows:

Converter Schematic:

These connections should be made:

I had to use a multimeter to figure out what number pins on the VGA side where what colour wires, as the wire colours made no sense.

Make sure you connect the 'Chassis ground' on the VGA to pin 21 (SCART-GND) on the SCART. The 'GND' on the converter schematic is referring to VGA pin 10 (Sync Ground) which, as the table says, connects to SCART pin 17.

When you are done soldering you can clip the SCART connector casing back around the connector keeping all your work safe! Remember to insulate anything that might contact when enclosed in the small space.

Extra info you may need

Some TVs do not automatically know they are receiving an RGB signal and so all you will get is a blank screen. This can be overcome by giving pins 16(+) and 18(-) on the SCART ~1-3V. This tells the TV it is receiving an RGB signal. You can do this using a 3V DC adapter. A tidier setup is to take power from the PC. Using one pair of CAT5e wire, connect the pins to the +5v and 0v on a PSU molex connector.

The other pin it can be useful to power is SCART pin 8. With ~5-8V it will set the TV to '16:9 AV mode' and with ~9.5-12V '9.5 to 12V'. Powering this will also automatically change the TV to the input when it is active.

Alternate method

Main article: HOWTO Setup MythTV in Framebuffer

MythTV can be set up in the framebuffer, though this is only recommended for advanced users.

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