Quote:
Originally Posted by
PanamaMike 
It's one thing to observe, it's another thing to "verify" or validate that what you're observing is really what you think it is.
I've seen folks demonstrate LCD timing lag by using programs and video cameras. For those with enough technical knowledge, there are ways to demonstrate what they are observing.
Unfortunately, I don't have the knowledge to do so, this is why I ask. After reviewing the thead, it's quite possible different people are seeing different artifacts. This is why I brought up the mud, which can look like jitter during certain pans.
I'm a bit surprised jitter is a problem since caching of the video should address the problem. For a long time, I thought choppiness I was observing with flash, HULU Desktop, was being caused by a bad HPET or clock timing issues. Turns out the real problem was due to repeated calls to flash action scripts which were being called more often than necessary. Once the software was fixed, the choppiness went away...This may end up being the same for Silverlight.
Also note network packet size can introduce less than smooth video. There are quite a bit of variables one has to look at when playing back streaming video on a PC; these issues just don't come up on an appliance.
Mike
I've considered using a high-speed video camera to record what is happening, but I don't have access to one. It certainly would provide objective proof.
However, everything that I see can be explained by the playback chain not hitting the vsync at exactly the right time. Since there is no tearing, we can be sure that updates are synced to vsync. When I set the refresh rate of my display to 24hz and display 24hz material, there should be zero telecine judder and every frame should be displayed. At 24hz dropped frames are very obvious. What I see when I do this experiment are dropped frames, but the playback diagnostics do not report any dropped frames. When the refresh rate is set to 60 Hz and 24 Hz material is displayed there should be a fixed cadence as frames are repeated. If this cadence is not consistent then you will get jerky, jittery playback. That is exactly what I see.
This is not a networking issue. Both networks that I tried this on have more than adequate bandwith and there is enough buffering in the playback chain that any minor variations in packet delivery times should not show up on the display.
However, in the final analysis it doesn't matter what the root cause is. The Netflix playback on a PC is unwatchable for me and many others because of this jitter. Nothing solves it: different CPUs, GPUs, networks, displays, drivers, OSes, Silverlight versions, etc. A media streaming box looks fine to me, and the PC should be at least as good.
