Multiple Delivery Mechanisms for Streaming

Personal Area Networks
Once content has been delivered to a particular device, how is playback affected as the user moves from device to device, selecting each for a particular task? The partial answer may be found in Apple’s popular iPod audio playback device. The iPod has a feature that allows recorded audiobooks, which are sold both on the iTunes store and the Audible site, to be roundtripped from iTunes to iPod and back again.

This roundtripping is fairly seamless: iTunes keeps track of where in the multi-hour audiobook it is; when the iPod is removed from its dock and the audiobook is selected on the iPod, the iPod will begin playing the audiobook at the same spot where iTunes left off. Upon return to the docking station, the iPod then informs iTunes where it stopped playing the audiobook so that iTunes can resume playback from that spot.

Streaming content delivery can expand the iPod model to a slightly more complex, but highly flexible, model. If content is downloaded to a particular device, such as a local computer or media server, that local device can then search for other available media-enabled devices—a home theater system with a hard drive, a laptop, or a PDA—and begin downloading a portion of the content to these devices.

Ideally, content would be loaded on to the secondary device in reverse order—from the end of the movie backwards—so that the content most likely to be played will be available first. If the content being downloaded to this secondary device reaches a point in the content that the primary device has already viewed, downloading to the secondary device will cease in order to adhere to copyright issues. Content would then continue to be erased from the secondary device as the primary device plays, effectively keeping the two devices synchronized and eliminating unneeded content from the secondary device, which typically has a smaller storage capacity.

When the secondary device moves off the personal area network, the primary device can be programmed to continue or stop playing. If it stops playing and the digital rights management key is handed off to the secondary device, the secondary device can then be set to play content back on a non-local device with existing technologies such as Bluetooth, effectively acting as a media server to a non-local monitor—a car video screen or a hotel room flat-panel or TV monitor. Roundtripping also would occur once the secondary device moves back into the personal area network. While this scenario may sound far-fetched, it is completely achievable with current technologies such as Bluetooth, 802.11 hotspots, and peer-to-peer networks.

Keys to the Kingdom
The key to emerging delivery networks is not just faster pipes or speedier CPUs. As streaming content continues to be encoded in better-quality compression algorithms, such as H.264, proponents and adopters of these technologies will implement them most effectively if they do so with knowledge in three key areas: how the content will be used, what emerging interfaces and compression technologies are most likely to benefit the end user from a quality standpoint, and how to transmit content properly across existing content delivery networks.