[mythtv-users] Seeking Advice

[Michael T. Dean]

On 07/25/2007 02:58 PM, Tim Phipps wrote:
> 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).

So you agree that you get a better result using 800x600 (for GUI)?  The
point is that 800x600 isn't possible using a PVR-350's TV out.

And, for what is, IMHO, the definitive opinion on "unscaled" TV out, see
posts from Cory Papenfuss.  Of course, when it all comes down to it,
"picture quality" is really a subjective argument (whereas "picture
accuracy" may be objective--though very difficult to measure).  So,
whether things happen without any scaling/deinterlacing/etc. or whether
the hardware is doing "unseen" filtering of the image, if the (specific)
end user thinks it looks good, it's a good way of doing things (for that
specific end user).  And, then again, there's also the placebo effect
(which I hope anyone on this list talking about improvements in picture
quality is able to see beyond).

Anyway, I highly recommend Hauppauge PVR capture cards (specifically the
PVR-150 and the PVR-500 /only/ if you're lacking PCI slots).  Likewise,
I highly recommend not getting a Hauppauge PVR-350.  Just don't blame me
if you're not happy with the solution you choose. :)

Mike