When the viewer then attempts to watch an Autobahn-enabled video, the software connects simultaneously to a few copies of the file at once, downloading pieces from several different networks and recombining them on the fly into the streaming video.
This kind of file “swarming” is familiar from peer-to-peer technologies such as Gnutella and Bittorrent, and the more copyright-friendly services like Akamai’s Red Swoosh and VeriSign’s Kontiki. But unlike those services, the Autobahn software does not rely on users to cache and upload data to other viewers.
Swarmcast calls the second and newer component of Autobahn HD adaptive bit-rate streaming. Using this, a publisher would encode several different versions of a video file, at different standards of quality. Software on the viewer’s computer would monitor the local connection, and then select the highest-quality version possible to be streamed.
This feature gives the video stream the ability to adapt as network conditions change. An Autobahn stream might start out at only middling quality, with the picture sharpening as the connection proves to be stable. If something later interferes with the connection, such as another user taking up network resources, the software could quickly readjust to a lower-quality stream.
This aspect in particular helps mimic the instant-on aspect of television, McQuivey notes. A mid-quality stream can start almost instantly, and then improve over the next few seconds, while an unbroken high-quality stream often requires a longer wait before beginning.
None of this guarantees perfect video quality, of course. Swarmcast, like its closest rivals, offers viewers the ability to use connections efficiently. If network conditions are poor, some buffering might still occur, or images might be highly pixelated.
The company is releasing the source code for its Flash player software for free online, so people can build their own customized interfaces or add components such as an ad-insertion tool. For a limited time, the company is offering free content hosting on its network, hoping to convince potential customers of the benefits of its multiple-network swarming service.
For now, the prospect is drawing interest–but many video companies are already looking elsewhere for quality improvements. Technology executives expect widespread adoption of the H.264 compression technology (the same one used by Apple’s iTunes) in a new version of Adobe’s Flash next year, and they say that it’s likely to offer more-substantial and wide-ranging improvements to the online-viewing experience.
In broad strokes, H.264 (also known as MPEG 4 video, or AVC) is the most recent of the video compression technologies approved by the Moving Pictures Experts Group (MPEG) standards body. As implemented in Flash, it relies more heavily than its predecessors on hardware instead of on software to decode the video, and it offers considerably clearer pictures at low bit rates than do most older technologies.
“H.264 is the most promising thing on the horizon,” says Joseph Papa, vice president of engineering for Veoh Networks, a popular Flash-based video-publishing site based in Los Angeles. “Technologies like Swarmcast’s are incremental improvements. They might offer a slight increase based on network conditions, but I wouldn’t describe them as game changing.”