This issue is doing my head in - hours wasted so far. I'm using Lovefilm Instant which also uses Silverlight.
The quick first question is this: I've read lots of threads where people say "right click" or "press CTRL+SHIFT+S" to access stream manager to change the settings. IT DOESN'T WORK!
It seems that people have some success using "stream manager" in Silverlight 5.0 and below, but since 5.1 I can't find anyone whose managed to access the advanced menu - just hundreds of people asking the same question as me.
I've tried it with hardware acceleration on and off, I've tried it full screen and windowed, I've tried it at native resolution as well as 600x800. Every single time, the jerkyness happens at almost exactly the same points in a pan, but it's not a regular stutter like 24fps pulldown. It might be fine for 1.5 seconds then judder for 10 frames, it might stutter for a frame twice in one second.
My PC, laptop and girlfriend's Macbook can ALL play other full HD content smoothly and without issue, the PC doesn't even struggle with Youtube 4k videos, and I don't have this trouble with any other non-Silverlight provider. Flash, mp4 etc - it all plays perfectly smoothly.
Seems pointless emailing Lovefilm because the many others that have say all the things they've tried, including clearing cookies and cache and updating and trying different browsers. Then after 4 weeks they just get a standard answer like "please clear your cookies" or some other nonsense.
SO many people are having this same problem, yet Lovefilm, Netflix, and also the MSPs in the Microsoft forum, just keep pretending it's not an issue.