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Shaw analog slowly degrading? (No, hardware issue)

3K views 6 replies 5 participants last post by  pcmacdon 
#1 ·
I've been using a home grown PVR (Mythtv with a PVR350) on Shaw
for 4+ years now, and in the last few months have noticed
a disturbing trend. Progressively more and more
channels look like crap when recorded to my PVR and no amount of
tweaking the hardware encoder has any effect.

On these channels, the picture suffers from combing, jagged edge effects
with horizontal lines jumping intermittantly.
And motion tends to exacerbate it the most. Were not talking
about a few artifacts here, it actually hurts
the eyes to watch it and is barely watchable.

At first just one or two stations were affected but now about half
of them have the problem. However, these same channels look OK on the TV.
Also hooking the PVR cable to the TV also looks OK.

Has anybody else witnessed this or anything similar?
 
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#2 ·
If you have less signal strength, then it can affect one device (tuner) more than another. Remove any upstream splitters as a test and also have Shaw check your signal strength. You should also check your various cables and connections to make sure they're good by undoing/redoing, trying a different RF-coax, etc.
 
#3 ·
I have noticed the same. Some of the worst channels are the US channels that have gone all digital. What does SHAW use to downconvert the digital HD signals to analog? Whatever they are using, the poor signal conversion is very annoying. I'm sure SHAW would like to have all of us ANALOG users go away and buy their digital converters!
 
#5 ·
I've seen differences in artifacts with analog and digital sources and with various connections. This could originate with Shaw but could be in the PVR picture processing or one of the TV settings. For example, a TV's comb filter will make the picture worse if used with an S-video connection and a digital source. With digital signals, very little processing is usually required. OTOH, I wouldn't be surprised if Shaw was causing the problems. Their handling of US analog signals was always poor. I doubt they put much money or effort into converting the new HD digital signals to SD analog. Shaw (and Rogers) would rather phase out analog TV than invest any money into it.
 
#6 ·
I forgot to mention that I also have a cable booster (which
I upgraded last year to handle higher channels).
Also, I tested disconnecting all other TV/devices and still
have the problem, so I don't think signal strenght is the issue.

My PVR350 does not have a comb filter so
I suspect the problem is due to mpeg'ing an image
that has previously been mpeg-ed (eg. feed from a US network).
But this is just a guess.

Also, I see this problem even if I grab raw mpeg encoded data
and display it on the PC, so it has nothing to do with the connection
to the TV.

I'd consider going digital but I've heard getting Mythtv to work with a
DCT is a pain (IR blaster?), and the shaw PVR's leave something
to be desired.

Another alternative would be upgrading to a newer PVR card
that has a comb filter...
 
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