In Theory: Can Cloud Gaming Replace Console?

Time is being called on video gaming as we know it. No less an expert than id software's John Carmack claims that consoles will fall to Moore's Law and that realistically, we're looking at two more generations of bespoke gaming machines before the curtain is drawn. The future is the cloud: gameplay over IP. The question is, what exact form will it take?

We have two working systems to mull over in the here and now: OnLive and Gaikai, both based on the principle of beaming your control inputs to a remote server that transmits back gameplay in the form of compressed video. The advantages are numerous: no need for game code on the client meaning no piracy, while loading is kept to a minimum (and masked rather well within OnLive's excellent front-end interface) with no lengthy installs. As the server holds all the game code, the player needs a simple dumb terminal and game controller, which - in theory - will never need to be upgraded. Both Cloud services have been seen deployed on a vast array of devices from iOS to Android, Blu-ray players and even TV. We've even seen Gaikai running on Xbox 360.

Both Cloud services have been seen deployed on a vast array of devices from iOS to Android, Blu-ray players and even TV. We've even seen Gaikai running on Xbox 360.

There's also the matter of convenience and access. Your whole game library is instantly available, you can play your games on multiple devices (anything with a controller input and video decoding facilities, basically) and integration options are mouth-watering: how about organising a multiplayer session within Facebook? Better yet, why not recommend games to your friends by letting them play the actual game within the browser? Both OnLive and Gaikai plan to have you playing real games launched directly from your Facebook feed - a killer concept that Xbox LIVE and the PlayStation Network would have real issues matching. The potential to expand the audience here is phenomenal.

Of course there are the downsides too. Concerns over lag - the time your controller inputs are reflected by the action on-screen - will never go away completely, but so long as there is a relative amount of consistency, the maths work out that the experience can be eminently playable. In a recent interview with Eurogamer, OnLive's Steve Perlman believes that his system could even outperform console:

"Video games today, when they're built for Xbox 360, PS3 or even PC, they have pre-render queues. In order to get as much realism as they can with the processing hardware they have, they introduce multi-frame lag in games. There is some period of delay before the result hits the screen," he says.

"We're able to compensate for that because we have state of the art servers with very high performance GPUs. A 2005 class Xbox or PS3 game, when you put it on a 2011 class server, we don't have to have that pre-render queue. Instead, we use that time for the network delay. The algorithm keeps getting better and better."

It's an interesting argument but the fact is that all games have latency built-in to different extents, and short of extensive re-engineering, the sort of lag Perlman is talking about can only be mitigated by throwing more power at the existing code, and it definitely won't be completely eliminated as he appears to be suggesting. For example, we measured latency on the Xbox 360 version of Bulletstorm running at 30Hz to be in the region of 133ms, without factoring in additional lag from the display. Conversely, the game running on an i7 with a GTX580 at 60Hz comes down to 84ms (with v-sync enabled).

In an environment where the server is running several virtualised game instances, it is unlikely that OnLive servers will be able to allocate the same amount of resources to Bulletstorm as our i7 games set-up - indeed, at GDC2010, Perlman talked about twice the amount of GPU resource per instance as an Xbox 360 - nowhere near our GTX580 set-up - but let's assume that this latency can be matched. This means that OnLive has to compress the video, transmit it and decompress it in just 50ms: a tough task. As it stands right now, we've seen a baseline lag of 150ms on certain OnLive titles - just one frame off Bulletstorm on Xbox 360, but on other games where performance is variable, response is correspondingly less solid, and occasionally downright lousy.

"We don't tune the system by some sort of scientific measurement on latency," Perlman continues. "We tune the game system from a human perceptual point of view to try to make it so the game plays as good as possible."

It's a bit of an odd comment (and Perlman doesn't expand upon how latency can be "tuned") but then cloud gaming is to an extent all about smoke and mirrors - making the experience playable and enjoyable even if the actual input lag is a touch on the high side. Actually being able to discern latency without a precision controller like a mouse is actually quite difficult unless you're comparing side-by-side with the equivalent local experience. To a certain extent, it either feels "right" or "wrong".