[mythtv-users] PVR-500 picture quality

Paul Gardiner lists at glidos.net
Tue Feb 2 08:24:41 UTC 2010

Joey Morris wrote:
> Paul Gardiner <lists at glidos.net> wrote on Mon, Feb 01, 2010 at 09:26:59AM +0000:
>> I'm sure there's some loss in the capture stage, but don't rule out
>> loss also at the playback stage when dealing with SD under MythTv.
>> My set up has dvb-t as source, so zero loss on the recording side,
>> yet it took me ages (and 3 frontend builds) before I achieved
>> image quality equal to commercial equipment. The trick at playback
>> is to do as little processing as possible, so:
>> 1 Set up the x screen to match the content 720x480. Scaling from
>> 720x480 to 800x600 will lose quality.
>> 2 Don't adjust the playback window to avoid overscan. Scaling from
>> 720x480 to 71Xx47X will really notice.
> I set the GUI width and height to 0x0 to force fullscreen. However, I
> did adjust my overscan in X using the TVOverscan option. Could that
> affect things? I'll play around with it.

I don't know how that works, but possibly yes. Also, when I was using TV out
there was an option with my chip/driver called TVDeflicker. Setting
that to anything but 0 called blurring. Messing about with those
settings made a huge difference for me with TV out, although I never quite
got perfection, and eventually swapped to using VGA to Scart for
output to the TV (not an option for many, I know).

>> 3 Don't use bobdeint or linear deinterlacers.
> I'll play around with the deinterlacers, too. Based on everyone's
> helpful responses, though, I'm guessing it's pretty close to as good
> as it can get.

Yes, quite possibly. You could try viewing your recordings on
a PC with Myth Player. That would more or less avoid any playback
loss (scaling up by large amounts doesn't lose much quality),
but it would still be difficult to do the like for like
comparison with TV showing analogue.


More information about the mythtv-users mailing list