Digital Cable TV and Artifacts

[Guest]

Archived from groups: alt.video.digital-tv (More info?)

We just switched to Comcast digital from Comcast analog because of a
good package they offered. The problem is the amount of digital
artifacts on just about all channels.....freezing, stuttering, audio
drops, pixilization, etc. Tried everything I could think of, including
using the S-Video output. Same problem. Sometimes it's worse than
others.

We've only had it for two days but if this is normal for digital I'll
be switching back to analog, much as I like the upgrade in other
respects. A tech will be out monday. I'm hoping a new box will correct
the problem. Any comments on this type of problem? Is this normal with
digital?

Thanks

 

[Guest]

Archived from groups: alt.video.digital-tv (More info?)

"George W." <geo_removethis_wirth@comcast.net> wrote in message
news:6s1nr0l7nn976hiacbukqd4fgbsd1tt6qb@4ax.com...
> We just switched to Comcast digital from Comcast analog because of a
> good package they offered. The problem is the amount of digital
> artifacts on just about all channels.....freezing, stuttering, audio
> drops, pixilization, etc. Tried everything I could think of, including
> using the S-Video output. Same problem. Sometimes it's worse than
> others.
>
> We've only had it for two days but if this is normal for digital I'll
> be switching back to analog, much as I like the upgrade in other
> respects. A tech will be out monday. I'm hoping a new box will correct
> the problem. Any comments on this type of problem? Is this normal with
> digital?
>
> Thanks
======
That's not typical for digital cable. Reads like you've got bad cabling or a
local amplifier or your converter is bad. A cable tech should measure the
signal level at several cable frequency bands to ensure they're okay. It's
the cable company's problem to fix, including providing a new cable
converter. Try unplugging the cable converter (AC) for a ~10 seconds, then
check images again. Also, make sure there's nothing blocking the bottom or
top converter vents to prevent overheating.
John

 

[Guest]

Archived from groups: alt.video.digital-tv (More info?)

"George W." <geo_removethis_wirth@comcast.net> wrote in message
news:6s1nr0l7nn976hiacbukqd4fgbsd1tt6qb@4ax.com...
> We just switched to Comcast digital from Comcast analog because of a
> good package they offered. The problem is the amount of digital
> artifacts on just about all channels.....freezing, stuttering, audio
> drops, pixilization, etc. Tried everything I could think of, including
> using the S-Video output. Same problem. Sometimes it's worse than
> others.
>
> We've only had it for two days but if this is normal for digital I'll
> be switching back to analog, much as I like the upgrade in other
> respects. A tech will be out monday. I'm hoping a new box will correct
> the problem. Any comments on this type of problem? Is this normal with
> digital?
>
> Thanks

No, freezes and audio stops are completely uncharacteristic.

The only artifact to expect to see is tiling ("pixilization" you called it)
related
to compression, where the flow of detail is too intense for the channel
bandwidth.
All digital TV is compressed and when too much of the scene has constant new
data
pumped in, the compression scheme may choke. If you're going to get it, it
might be
at times when the camera pans a crowd scene (as in sports events, as they
follow the action with the stands in the picture). Fades will do it, too,
'cause every
part of the screen has to change at the same time in a fade.

The worst one I ever saw was a swimming pool. The rippling had so much
random
motion that the surface looked like a checkerboard of mixed blues.

Unlike analog, looking at the digital picture asnd knowing it's getting
destroyed by
interference is not usually possible. Digital cable uses frequencies that
are also used
over-the-air. If your problem is just on some channels, consider the cable
may be
letting some signals leak in. Got cell-tower?

 

[Guest]

Archived from groups: alt.video.digital-tv (More info?)

George,

This is not normal, my bet is there is a source of signal loss somewhere.
Have the cabletech come and run a signal line test. I thing there are loss
fittings somewhere on the line or a problem with your downstream that can be
fixed with recabling.

Phil

"George W." <geo_removethis_wirth@comcast.net> wrote in message
news:6s1nr0l7nn976hiacbukqd4fgbsd1tt6qb@4ax.com...
> We just switched to Comcast digital from Comcast analog because of a
> good package they offered. The problem is the amount of digital
> artifacts on just about all channels.....freezing, stuttering, audio
> drops, pixilization, etc. Tried everything I could think of, including
> using the S-Video output. Same problem. Sometimes it's worse than
> others.
>
> We've only had it for two days but if this is normal for digital I'll
> be switching back to analog, much as I like the upgrade in other
> respects. A tech will be out monday. I'm hoping a new box will correct
> the problem. Any comments on this type of problem? Is this normal with
> digital?
>
> Thanks