I subscribe to Comcast here in Western US, really no choice it is the only game in town

[G+_Rickbearcat]

Rud Dog So you say that they came out a year ago and you passed their tests with flying colors, eh? Did you verify this to yourself, i.e. turned on your TV's and made sure that the problem was cleared up? I bet you did, otherwise, you wouldn't have allowed the tech to leave your place.

 

So, what has changed since that last visit from the technician in the past year? If everything was working well then, what have you done to the "system" that might have changed things? Start thinking about what you've done from the day he left to today and maybe you can pinpoint the area most likely to have caused things to go haywire. This is all I've got on solutions at this point without having to come to your house with test equipment in hand! Again, best of luck.

[G+_Rud Dog]

Travis Hershberger Will do. That will require a quiet house meaning no one home or recording anything anything short of that and I won't have a quiet house. Thank you for the testing ideas.

[G+_Rud Dog]

Rickbearcat will put on the old thinking cap. Thank you for helping out.

[G+_Jason Marsh]

Five questions to ask:

 

1) How are the streaming boxes connected to the network?

-- If over WiFi or coax (HPNA) , get/make a long patch cable and try over ethernet.

-- If already on ethernet, verify that the cabling performs to standard. Speedtest from a laptop over the run in question to verify you get the same speed from any/all wired nodes.

-- If HPNA is in use, check connection stats from the streaming devices. HPNA can be fickle. Clean/re-terminate any connections with less than great link quality.

 

2) Is something resident on your network causing the problem?

-- Shut down all network devices and bring each up alone to test connectivity, link quality, throughput/speed, and presence of the fault symptom (pixelation).

-- If you recently brought a TOR node online, installed a sync/torrent service, or a SamKnows box, you could be creating the choke point by taxing upload throughput. You need good upload to maintain a healthy & fast TCP connection for all your client machines. If the streaming service is over UDP this may not matter.

 

3) Did your ISP recently have a marketing push to sell greater bandwidth to everyone in your neighborhood?

-- Cable is a shared medium in your neighborhood. If they've recently added or upgraded many customers in your area, the cable equipment servicing your area may be oversubscribed. Test at different times of day to determine if it's just "the internet's busy".

 

4) Does the symptom occur when streaming recorded shows from one device to another, with recorded shows ON the viewing device, or only when streaming FROM the internet?

-- Between devices; local network problem

-- Stored on the device used to watch; device problem

-- From internet only; back to questions 1, 2, 3.

 

5) What kind of real download speed do you get when downloading a large file from the internet. Time an ISO download from Ubuntu, Microsoft, or other large entity that should have a solid CDN delivering their bits. Do the math and figure out your REAL download speed. You may have a great connection to your ISP's central office/aggregation point, but if their peering arrangements are inadequate, the problem could be pretty far from your locality and no tech they send out could find anything wrong.

[G+_Rud Dog]

New update. Don't know why I didn't notice this before but the described pixelation only happens on channels 2 and 5 believe they are Fox and CBS. Still pondering this one.

[G+_Jason Marsh]

Do those channels stream at a higher bitrate than the others? Perhaps you can change the TV type in the comcast box to force a lower resolution. Set to 720p, as most aren't streaming higher than that anyways, but there's a chance the two troublesome ones are, at least in your locality.

[G+_Rud Dog]

Jason Marsh Will check and see if the two channels mentioned are in fact coming over at a higher resolution then 720p. Thank you.

[G+_Jason Marsh]

My parents have AT&T (VDSL) now, after leaving Comcast (coax) over video quality issues.

 

Comcast wouldn't spend any money to improve the reliability of their service, even though it was just bad coax in the neighborhood. They were out at least a dozen times in the last year before my parents left for AT&T, and never did much more than note the signal quality problem, replace the CPE, and install a new drop to the service location. None of this ever really solved the problem.

 

Their problems on AT&T stem from one of the two pairs supplying their VDSL connection. There are no unused circuits to swap on the local loop, so they're stuck with a poor-quality link. If anything is recording or Windows is downloading updates, there isn't enough bandwidth left to actually watch tv without pixelation or complete loss of the video feed.

 

Their only other options now are satellite and terrestrial OTA. I've never been satisfied with satellite tv, but maybe I can convince them to cut the cord and go OTA like I did.

[G+_Rud Dog]

Update: in my attempts to figure out why a couple of channels on my Comcast video feed were pixelated decided to run Spinrite on my Tivo drive. Well that didn't work out, while trying to get Spinrite CD to boot I hosed my PC settings and had to revert to reinstalling Windows 8.1.

Come to think of it never did get Spinrite booted, that's another mess.

 

While I had the drive out I took the Tivo case out to the garage and gave it a good blow out with the air hose. Re seated the Comcast scrambler card (lack of knowing what it is actually called) and placed the Tivo unit back in service. To my surprise the first few nights the problem was gone now I just have to wait and see if this fixed it or just kicked it down the road a piece. Hopefully this can help someone else if they stumble on this particular experience.

[G+_Rud Dog]

Turns out I was correct in my assumption, kicked it down the road a piece, although it doesn't do it as regularly as it did before the re-seating of the card. So going to take the cards down to Comcast and ask for new ones. Will keep you posted.

[G+_Rud Dog]

As mentioned took the two converter cards into Comcast and they gladly exchanged them for two new ones. So far going on the first week since install, no problems.

[G+_Rud Dog]

It's back...how do I test if its the Tivo or the incoming cable signal?