Here is how you carry out and explain a latency test:
http://www.eurogamer.net/articles/digital-foundry-vs-project-natal-article
Even running in real-time, the video of me waving my right arm up and down gives some indication of the lag, but it's important to emphasise the "some indication" bit in the strongest-possible terms. The video recording was made at 1080i - 60 fields per second - and this can be interpolated out with reasonable accuracy to a progressive 60FPS video. Frame-counting from moving my arm down to the on-screen Avatar following suit appears to be close to 200ms (12 frames, a fifth of a second). Before we go ballistic on this, it's got to be put into context in a number of respects:
- We don't know the latency of the display, which could be anything between 1-5 frames (it's a Samsung, so it'll likely be towards the lower end).
- We don't know the latency caused by the game code - it varies dramatically, even between 30FPS games.
- Of course, Natal isn't finished yet, and best guestimates say it'll be 14 months until it's out in the shops. There's a very strong possibility that the final production unit will be different.
With that in mind, an educated guess on the optimistic side would be that this Breakout-style demo operates between 133ms to 166ms - effectively the same range of response as Halo 3 working with the joypad. Assuming it's an ultra-quality, low-latency display, that delta shifts to 166ms-200ms - similar to Killzone 2/GTAIV controller lag. Certainly in this test, the latency is noticeable, and I think it's clear to see when the video is running in real-time, but until we get the tech into controlled conditions, preferably in a straight head-to-head with the conventional joypad performing like-for-like tasks (dash navigation, for example), a precise latency figure isn't possible. As I've said, what we see here is an indication of likely performance.
