[mythtv-users] Analog tuner picture grainy

[Brian Wood]

On Sunday 05 April 2009 15:20:44 Steve V wrote:
> I have a PVR500 card. The picture from either the tuner (tuning into UHF
> analog broadcasts) or the composite input is very grainy. Whereas, the TV
> looks fine using the same aerial connection or composite source.
>
> I've tried all sorts of tests.
>
> I moved the card to a different PC (a linux box) still the same grainy
> look.
>
> Tried a different card in this PC (a Pixelview CX88) still the same grainy
> look.
>
> Tried
> cat /dev/video0 > /tmp/test.mpg
> mplayer /tmp/test.mpg
>
> still grainy.
>
> I have read that it may be something to do with bitrates, I increased the
> bitrate under recording profiles (I increased the default profile as I
> guess this is the one that is used when watching live TV). Still grainy.
>
> Just to confirm the same composite source straight into the TV is not
> grainy.
>
> Does anyone have any suggestions? 

The quality of PVR recordings is somewhat less that what I would 
call "Broadcast Quality", but it can be pretty good. I can see the 
degradation in my own PVR recordings, but so far nobody else in the household 
can tell the difference.

People have different sensitivities to this sort of problem, so without 
actually seeing what you are talking about it's hard for me to tell if you 
have a setup problem, or if what you are seeing is normal for PVRs.

Can you put up a short clip somewhere I and others could get it?

If you could tell us what parameters (resolution and bitrate) you are using it 
would also be helpful.

There are a lot of parameters you can tweak on the PVRs. There is a lot of 
discussion of this on the IVTV and other forums, ie:

http://www.mythtvtalk.com/forum/general/5939-how-can-i-improve-tv-picture-quality.html

Note that a PVR-500 is basically a pair of PVR-150s, so discussions of the 
150s are relevant to your problem.

-- 
beww
beww at beww.org