[Openchrome-users] Using TV resolutions without TV encoder

[John Robinson]

On 04/03/2009 12:45, Ian Blackwood wrote:
> Hi,
>  
> I have a EPIA EN15000G board which is a CN700 / VT1625.
>  
> Previously this was outputting to a PAL TV on the SVideo and the 
> hardware acceleration was working. The only drawback was an amount of 
> overscan.
>  
> I now have a TV with VGA input so I am trying to get higher quality 
> using that connection.
>  
> What I would like to achieve is:
>  
> 1280x720p 50 Hz for MythTV GUI but 720x576 for my Standard Def video 
> playback (staying below 1024 to get hardware acceleration). MythTV lets 
> you do this provided your video provides the resolutions you want.
>  
>  
> I have tried setting the TV type to 720p and this outputs 1280x720p 60 
> Hz and the TV displays it without overscan. :-)  Problem is I cannot 
> then get 720x576.
[...]
> I am thinking these are the modes used for the different "TVType" 
> values. What I don't know is how I would make a modeline from the above 
> information !
>  
> Is there anyone who can point me in the right direction (or have a 
> xorg.conf for a similar setup ?)

If you're using the VGA output, you don't want to set TVType at all, and 
  Option "ActiveDevice" "CRT". Then you can use more modes. You may 
still not get down to 720x576 without setting VertRefresh and HorizSync 
manually for your monitor, and you won't get any lower than 720x576 50Hz 
non-interlaced i.e. 720x576p. My big flat-screen monitor won't do 
720x576 at 50Hz properly anyway, it gets recognised as 720x480 at 60Hz and 
resizes weirdly.

Here's a modeline if you need one:
# 720x576 @ 50 Hz HSync: 31.25 kHz
ModeLine "720x576" 27.00 720 732 796 864 576 581 586 625 -HSync -VSync

Hope that helps.

Cheers,

John.