[mythtv-users] Recording/live-tv video quality (aka do PVR150 encoders suck?)

Brian Wood beww at beww.org
Mon Jan 28 04:25:08 UTC 2008

Brad DerManouelian wrote:
> On Jan 27, 2008, at 8:08 PM, Scott Traurig wrote:
>> No s-video output from the STB is available.
>> Scott
> You may be experiencing some RF interference with your computer 
> components, but it's hard to diagnose if you can't take the RF out of 
> the equation. Do you have another s-video source you can try to see if 
> the quality is better?  Not sure what you could do it if is better. 
> Shielding? Maybe switch slots on your motherboard to see if it's less in 
> another one?

I don't know what your problem is, but I can tell you it *is* a problem, 
not the inherent performance of the PVR cards.

I record with PVR-150s from analog cable and S-Video from a DISH receiver.

While I can see the difference between these recordings and the original 
source material, nobody else in my family can.

If you know what to look for no recording technique is transparent, but 
with the PVRs the degradation is nowhere near enough to interfere with 

In fact I continue to be amazed at the quality you can get with a PVR 
for under $100. I used to work with encoders/decoders costing hundreds 
of times as much (albeit long ago).

All I can suggest is that you start eliminating things one at a time. 
Look at the quality of your initial signal, make sure it is as good as 
it can be. Try replacing/substituting cards, moving cards, using the 
cards outside of Myth (cat a file form the card then play it with VLC or 
mplayer). Make sure the PVRs have sufficient pure DC power. Check all 
the interconnect cables, twice.

Check the grounding, shielding etc.

Basically what you say is that DVDs look better than your cable TV, not 
surprising really. PVR recordings will look worse, but it's hard to 
quantify by how much, and everyone's eyeballs are qualitatively different.


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