[mythtv-users] DVI v. Component

[Gert van der Knokke]

Cory Papenfuss wrote:

>     As an example, consider my GeForce2 400MX I bought 2 years ago or 
> so. I wanted the potential for video in/out on it, so I got one that 
> said it did both. I was unpleasantly surprised when I actually started 
> using it to find how crappy the quality was.  Turns out they used a 
> crappier video output chip that also had video in.  Marketspeak said 
> it was great, and only by looking at the datasheet on the chip could 
> you see that it was limited to 240 lines of output. Basically 
> worthless, but I didn't discover that until way too late after I got it.

But this is not the Geforce chip's fault, it is the TV-Out encoder chip 
which can't handle interlace and thus always creates a non-interlaced 
picture (hence each line is simply doubled)

>     That's the main reason I use my funky VGA->NTSC transcoder box.  
> Any VGA port can output high quality video at TV resolutions (or else 
> it would be an even crappier computer card).  I bypass the flicker 
> filtering since its only use is to make still computer-generated 
> text/graphics look better.  Video... especially captured NTSC video... 
> should be displayed without flicker filtering to minimize processing 
> and distortion.
>
Your transcoder box does interlace then ?

>     WRT scaling, it's also why I use a 720x480 modeline on the funky 
> VGA->NTSC transcoder box... don't need to scale anything while viewing 
> max quality ivtv or dvd video.  Now, if only I could get 
> pseudo-genlocking to force vertical sync between capture and output 
> cards.  Don't some NVIDIA driver thingies do that and support 
> interlaced output now?
>
Still all these efforts are in vain since for example DVD's can be 
recorded in different resolutions, especially vertically there is a lot 
of spreading.. Your average stand alone DVD player scales the output 
nicely onto the standard 4/3 or 16/9 canvas but you'll never now how 
much lines or pixels per line there were originally unless you start to 
rip the DVD.

MythTV does a similar thing, it displays an edge to edge image but when 
I look at the raw recordings from the PVR250 it has  left and right 
black borders.. So MythTV is scaling too.. How can one really know if 
the image is 1-to-1 ?

Gert