[mythtv-users] Seeking Advice

[Tim Phipps]

On Wednesday 25 July 2007 6:10 pm, Michael T. Dean wrote:
> IMHO, you
> can get a much better result using a video card running at 800x600 or
> 1024x768 with the TV-out chip sampling from that picture.  (And, BTW,
> regardless of what people may tell you, there's no equivalent of 1:1
> pixel mapping for SDTV using a TV out.)

True, but only because pixels don't exist for SDTV with a TV out. Lines do 
exist and they are important. Using a TV-out chip to sample is going to 
involve scaling and deinterlacing, both of which will degrade your picture.

You can get TV out at SDTV native resolution and I think it looks better, 
especially when watching interlaced material. I'm using an EPIA6000 as a 
frontend and using the 720x576Noscale mode makes all the difference (it turns 
off the scaling). TV recording is from a couple of Freecom DVB-T USB dongles 
so the source is very crisp. I use 800x600 for the GUI mode so that the 
frontend doesn't have to scale the theme images, and the scaling is turned on 
so horizontal lines don't waggle up and down. It also underscans so I can see 
the whole display.

In the frontend setup I turn on the custom modelines and Myth uses RandR to 
switch to 720x576 for programme display. It runs at about 16% CPU and gives a 
better picture than the TV's own analogue tuner. I used to use 800x600 before 
I got the EPIA and I could see the artifacts from the scaler (slight double 
imaging on moving objects, like watching NTSC programmes that have been 
converted to PAL).  BTW it boots from a 4GB flash disk-on-module and being 
fanless it's silent, shame the same can't be said of the TV's flyback 
transformer.

I'm not looking forward to the day I have to replace the TV and there is only 
LCD, somewhere along the line there's going to be a deinterlacer and it will 
probably be pot-luck as to how good it is.

Cheers,
Tim.