Towards Optimal Internet Video

Streaming multimedia over the Internet has been a work in progress for more than a decade. In 2001, audio streaming had been well-investigated. But with the advent of high-speed technology such as ATM and Ethernet, interest turned toward streaming video. With barely enough network speed to do it at the time, people considered how to adapt video to application layer streaming.

One survey addresses solutions to the challenges on three different levels--encoding, application streaming, and operating system support. It discusses how the data can be compressed at different levels, and how applications can choose which quality-level to stream the data at. It does not assume that video will be streamed over TCP, but shows how UDP can be used with error correction schemes. It even shows how an operating system could be changed to better accommodate a video application.

While many of the same techniques discussed in the survey are still widely used, video streaming has changed and improved since then. Due to the improvements in Internet architecture and the increasing demand for Internet video (and I will add multi-core processors), a variety of other strategies are used to effectively stream video.

Because of high demand for video from certain sites, P2P technologies are used to improve scalability. P2P methods such as those used by BitTorrent are being used to offload the stress on servers to clients and other network hosts, allowing a larger number of clients to receive video.

Most Internet video today is streamed through TCP. This is because network capacity is capable of transferring normal-quality video in a timely manner in spite of the overhead required to ensure no loss and packet ordering. It is also used because it provides congestion control; in other words, it is friendly to other data streams in the network.

But video is loss tolerant to a certain extent, and overhead could be saved in the case of streaming high-density video. Could a video transport-layer protocol be helpful that omitted the overhead required for data integrity, and had the network-friendliness of congestion control?