Follow The Bandwidth
Streaming has applications in both the consumer Web space and the corporate/ institutional world (Internet and intranet). But the availability of bandwidth is vastly different in the two realms, and that directly impacts the extent to which the technology is actually used. "For the average consumer," says David Heppe, VP of marketing & business development at Telestream, "streaming has been hyped beyond the level of current reality, mainly due to network infrastructure limitations, specifically last-mile connectivity."
Trying to stream video without broadband is more than a little masochistic. And with estimates of household DSL and cable-modem penetration generally in the 10% range, it's obviously going to be a while before streaming media can attract an audience in any way comparable to that of television. Most companies and institutions, on the other hand, already have at least DSL connectivity to the Internet and 10Base-T networking to every desktop. No wonder, then, that the vendors of streaming products and services generally see business, education, and government as their most promising markets for the foreseeable future.
"We've seen rapid adoption of streaming video in the corporate space," says Scott Gordon, VP of marketing at SeeItFirst, a vendor of interactive video products for corporate communications and training. "Applications include Webcasting large corporate events, training internal personnel, informing shareholders, training sales partners, extending customer service and support-basically efficiently disseminating important and timely information in a captivating and interactive Web-delivered medium."
Greg Lowitz, general manager of the Webcasting Solutions Group at Pinnacle Systems, says his company is not only selling production and encoding systems to the corporate market, but has also integrated streaming media into it's own corporate operations. "We use streaming in- side and outside our company on a regular basis now," he says, "whether it's for a CEO speech on our quarterly financial performance or a sales-channel training seminar to our dealers." The company also posts demos, live events (such as press conferences), and training on the Pinnacle Broadband Network (PBN) section of its public site.
Mike Nann, who handles technical marketing at video gear vendor DPS, agrees that training is one of the primary applications for streaming video in the corporate market. "It's often easier to convey concepts as moving visuals than as still images," he says, "and streaming video provides corporations with a means of distributing these moving visuals. This can save significant travel costs while increasing productivity, because streaming video can be used as an alternative to face-to-face training sessions."
A similar phenomenon is at work in education. "In recent years, we have begun offering Web-based downloading of educational information as RealMedia files," says David Matney, director of the Video Engineering Group at the Chapel Hill campus of the University of North Carolina School of Medicine. "The availability of materials 24/7 from a server is very important for students. It lets them work at their own pace and look at materials when their schedule permits."
Less is More
The source files for uncompressed video and audio content are huge, yielding a flood of data that can quickly drown almost any network. So the key enabling technology of streaming is data reduction, which is used to reduce the flood to at least a stream (or in the case of Web streaming, a trickle).
There are a few simple things one can do to reduce the bandwidth requirements of streamed media. In video, for instance, one can lower the frame rate (e.g. 15 fps instead of 30) and resolution (e.g. quarter-screen 320 x 240 pixels rather than full-screen 640 x 480). But these steps alone aren't sufficient to yield streamable data rates. So source files are encoded using a compression/decompression algorithm (codec), and then decoded on playback. The degree of compression-and the resulting quality-varies depending on the bitrate of the source file and the bandwidth available for streaming.
A wide variety of codecs are used for video and audio today, but most are designed around two basic techniques. One is to express more efficiently the redundant information generally found in temporal media. The resulting data stream should be bit-for-bit identical to the source when reconstructed by the decoder during playback. Unfortunately, such lossless compression doesn't go far enough in reducing the bitrate. So most video codecs also employ "perceptual coding," in which the encoder-based on assumptions about human perception-discards those bits that will likely be missed least by human eyes or ears.
Perceptual coding has advanced remarkably over the last decade, making it possible to stream recognizable content through smaller and smaller pipes. But limited bandwidth still imposes severe constraints on quality. Suffice it to say that in the Web-streaming context, the term "near-VHS quality" is used as a compliment.
Most codecs allow for encoding over a range of different bitrates to support transmission over connections of different speeds. For audio, common codecs include RealAudio, MP3 (MPEG-1, Layer 3 audio), Windows Media Audio (WMA), and MPEG Advanced Audio Coding (AAC). For video, those who favor a standardized solution are rallying around MPEG-4, but proprietary formats-Real, Windows Media, and QuickTime (Sorenson Video)- are the most popular. The leading companies are continually trying to squeeze better quality into fewer bits, and they leapfrog each other regularly. As the codecs change, the software players that run the decoding algorithms on client machines must be upgraded accordingly.
For companies contemplating streaming any significant volume of material, deciding on the appropriate codec is just the start. If the encoding is to be done in-house, rather than by an outside service, it quickly becomes apparent that there has to be an efficient system in place for batch preprocessing and encoding of multiple source files to multiple codecs and bitrates. Among the many solutions available for encoding, Media Cleaner Pro from Media 100 and Sonic Foundry's Stream Anywhere are examples of approaches based on internal computer processing, while systems from companies such as Pinnacle Systems and Minerva Networks are built around external hardware units.
More comprehensive than simple encoding solutions are systems that combine encoding, distribution, and tracking into a single automated workflow. A video source (live feed, tape, or digital file), for example, might be automatically captured, optimized, encoded for different formats and varying bitrates, and published (posted) to the servers from which the files will stream. Systems along these lines are available from vendors such as Anystream and Telestream.
In addition to encoding and distribution, an organization that deals with video and audio on a large scale-generators of content for broadcast or cable, for instance, or enterprises with a large archive of promotional and training material-will want content management solutions to keep track of the assets they have available to be streamed. Virage is a leading vendor in this category, offering an Internet Video Application Platform that includes searchable database capabilities for video files.
With solutions now available for every step of the chain, both the efficiency with which streaming media can be prepared and the ease with which it can be played back are light-years ahead of where they were back in the mid-1990s. But while tools can facilitate implementation of streaming, they can't by themselves make streaming commonplace.
"Technological optimizations are critical," says Matt Cupal, senior VP for strategy and business development at Sorenson Media. "But users aren't going to want to know what codecs or players to use, or to learn about what network protocols are best suited to their needs. For broad adoption, streaming video cannot continue to be a novelty. We've got to wrap the core technology inside go-to-market solutions. The greatest impact on the success of our industry will come from business-centric optimizations that solve business needs."