Microsoft says it’s found a way to cut the bandwidth needed for cloud-based gaming by 80 percent. It shifts part of the work to the user’s device, so results will likely be variable.
The company has been working with researchers at Duke University and has come up with a tool named Kahawai, the Hawaiian word for “stream.” It aims to deal with the problem that while streamed games, with the majority of the work done by a remote server, can allow top-notch games on less-powerful devices, the resulting bandwidth makes it less viable for anyone on a mobile data package or fixed-line broadband with a data cap.
The Kahawai solution tries to find a happy medium between pure device gaming and pure cloud streaming when it comes to the work of generating graphics. It means the user’s device will either produce a basic ‘sketch’ of every frame, completely producing selected frames (at least six per second but more depending on capabilities) or a combination of the two. The remote server will continue to do the bulk of the frames and complete the fine detail.
The basis of the technology is that many of the ‘big picture’ elements of an on-screen image won’t necessarily change that much from frame to frame. Instead it’s more minor changes such as shading that help create more impressive graphics. The system also takes advantage of the H.264 video compression format.
The researchers tested the game on Doom 3 and found that the average bandwidth needed to stream it was cut by 80 percent without any obviously visible decline in the graphics. They also asked 50 ‘hardcore’ gamers to carry out a set task (killing 12 monsters on a specified level) and found that not only did they subjectively rate the performance of the game as the same both with and without the Kahawai tool running, but objectively the player performance didn’t vary significantly with or without Kahawai. The testing also showed the response times were largely identical in both tests.
Testers used one of two devices: a high-end PC with graphics card and a Microsoft Surface Pro 3 tablet. The general pattern of Kahawai not affecting performance was consistent across both devices.
According to the researchers, the tool can also be modified to allow the game to continue running without an active Internet connection, albeit with a noticeable drop in graphics quality. The idea here wouldn’t so much be to target offline play, but instead to make game streaming viable on connections which have the occasional dropout.