• United States
by Steve Taylor and Larry Hettick

H.263 squeezes video into slow links

Jan 15, 20032 mins

* Closeup on H.263

Today, we’d like to acquaint you with a way to offer video services using the ITU-T standard H.263.

Part of the H.323 family of protocols, H.263 specifies a way to send video over IP. Like its cousin H.261, designed for implementing ISDN-based video using Nx64K bit/sec channels, H.263 is designed to offer video – only in low-bit-rate environments, below 64K bit/sec. (For more on the family tree of H.323, H.261, and H.263, check out the links below.)

Technically, the H.262 standard specifies content and format for streams of both video encoders and decoders. Since H.263 does not specify the audio channel streams, users should make sure the audio channel implementation follows a suitable audio standard implementation to assure both audio quality and synchronous delivery of the video and audio.

Using H.263 offers several advantages. Not only does it work where bandwidth is below 64K bit/sec, but the video quality also ranges from “as good as TV” to “much better than ISDN.” The other advantage is that, by using H.263, video is simply one more IP application to manage in a converged environment. 

Relative to wireless, some companies like DoCoMo, HP and Phillips are looking toward H.263 as one alternative to providing video over IP over wireless, although not much has been published otherwise about H.263 in the wireless environment.

Next week, we’ll take a look at another video-over-IP standard specifically designed for mobile: H.324M.