burst.com Technology-Understanding Faster-Than-Real-Time: Page 1

The Technology Behind Burstware®

The demand for high quality video delivered over networks continues to grow, spurred on by advances in network and data-encoding technology. Multimedia data delivery technology must meet several key technical challenges, however, in order to meet the demand.

The Challenges of Video Delivery

To be successful, a network video delivery technology must meet these technical challenges:

Provide jitter-free, eye-catching images and CD-quality sound
Make video delivery affordable by providing the maximum number of videos to the maximum number of viewers at a minimum cost
Intelligently manage network resources
Support open standards to ensure smooth integration with evolving encoding schemes, multiple platforms, and existing applications

Jitter-Free, Eye-Catching Images

Even the most reliable networks are subject to server and network leg failures, and everyday network inconsistencies and fluctuations. This results in the jittery, freeze frame quality that plagues most internet and many intranet viewing experiences.

Ideally, the viewer is insulated from network problems. A robust data delivery system handles downed servers, routers, and network legs; as well as network noise and delays; while the viewer enjoys an uninterrupted viewing experience.

Streaming's Constant Bit Rate Exposes Videos to Disruptions

Conventional data delivery schemes transmit audio and video data in a stream that flows at a constant bit rate. The server sends data at this rate and the client plays at the same rate. This is known as real-time streaming.

In order to keep the video image on the client screen moving, data must arrive over the network at a constant rate and exactly when needed. Streaming's "just-in-time" delivery scheme means constant exposure to network disruptions. The inconsistencies and fluctuations endemic to the network environment prevent a constant and reliable flow of data. Because streaming technologies match play rate to delivery rate, any data delay or loss will show on the viewing screen.

Streaming's Limited Buffering Scheme

Real-time streaming architectures offer limited client-side buffering, but this scheme presents two problems, both due to the fact that streaming delivers data only at the rate at which it plays the data:

The buffers tend to be too small, because large buffers result in delays at start-up time, while the buffers fill. Video viewing cannot begin until the buffer is full and data delivery has stopped; otherwise, the buffer never fills up.

As the buffer gets depleted because of network problems, streaming architectures either stop video play in order to fill up the buffer or allow the buffer to deplete.

Regulated Bursts Prevent Video Disruptions

The Burstware® server delivers data in large bursts. At delivery time, the information is dropped into a large buffer on the client machine at a rate faster than what is required to keep video playing on the client screen.

This provides the client with a stored buffer of cached data from which the client draws to play the video onscreen.

Client Shielded from Network Disruptions

The Burstware® architecture protects the client from changing network conditions. Should the flow of data across the network slow or cease, the client remains unaffected, continuing to play the data from its local buffer. As the network recovers, the buffer resumes filling at a Faster-Than-Real-Time™ rate, giving the client a "reserve" of data in case of subsequent network disruptions.