My problems with Netflix HD streaming started the day after Thanksgiving. Before that, I had been getting extremely clear HD fron Netflix on my Apple TV 3, Sony Blu-Ray player, iPhone, iPad, and MacBook Pro.
Except for the MacBook Pro, which has an ethernet connection, all of the devices are getting Netflix over my WiFi network.
My ISP is Comcast, and I'm consistenlty getting download speeds of 55 MPS over WiFi with an AirPort Extreme router.
All other streaming video sources work fine on all my devices. These include Amazon Video on Demand, Hulu Plus, iTunes (video content I have purchased or rented but not downloaded to my computer), Smithsonian Channel, ABC, HBO Go, etc.
When I watch Amazon Video on my Blu-Ray player, it's showing connection speeds of 5 to 10 MPS and HD looks fine. But when I watch Netflix on the same Blu-Ray player, the connection speed drops to 1 MPS or lower, and the stream either freezes up, or it looks worse than standard definition and is unwatchable, or both.
On the ATV 3, I get a decent Netflix HD signal for the first 30 to 90 seconds, then it stops for a second, and the image becomes so blurry that it is not watchable. I'm not being an HD snob, either. It's worse than a really bad VHS tape made from a very old video source.
The problem seems to be a lot worse after 5:00 PM.
At first I assumed it must be my WiFi router or my cable modem, so I re-set both of them, as well as the Apple TV. It still looked terrible. Netflix even looked bad over LTE on my iPhone, which would seem to indicate that neither Comast nor my WiFi network were the cause of the problem.
So I called Netflix. The first guy I spoke with emailed me a link to their webpage with troubleshooting measures. I'd already found that page myself, and I'd tried all of the suggestions, and none of them worked. He told me that since Netflix streams their video differently than other services, it requires a consistent network speed. OK, I get that, but I have a consistent network speed that is a lot higher than Netflix requires.
I called Netflix again, and this time I was a little more persistent. The woman was polite, but her message was clear: "This is not a Netflix problem. It is either your home network or your ISP. Check your WiFi network again, and then call Comcast." I asked her how she could be so sure it wasn't a Netflix problem, and she said if it were, they would know about it from customer complaints. But of course, if they are refusing to believe the reports from customers like me and others who have commented here, they really have no way of knowing.
I called Comcast, and the support person was more helpful. He confirmed that my internet connection was fine.
One theory I have is that a lot of people bought devices that can stream Netflix during the holiday sales, and they signed up for Netflix's free trial, putting a big hit on the Netflix servers. Whatever it is, I'm convinced it's a Netflix problem.
For now, I'm using my iPhone to access Netflix. The signal still looks really bad at first, but if I move the progress bar button back and forth really fast, eventually I can get a decent HD signal. Once I have a good signal, I send it to my ATV using AirPlay.
This is not a satfisfactory fix, but it's OK for the short-term. If Netflix can't fix it fairly soon, I'll have to drop the streaming and just stick with their DVD/Blu-Ray service.