The evolution of encoding

Webcasting — the transmission of audio and video over the Internet and other networks — is more than a buzzword. Despite a rough economic year for nearly all things Internet, the webcast industry continues to evolve. Video producers are now moving from desktop encoding to standalone, rackmount webcasting units. This month we'll go over the key differences between the standalone units and the more traditional, software-based desktop encoding systems.

As the technical manager for the professional postproduction division of DPS/Leitch Technology, Mike Nann has been involved with the webcast industry since its infancy. His company currently offers the dpsNetStreamer, a rackmount, standalone video and audio encoder that allows producers to encode live video and audio sources for the Web in realtime. The product provides as many as six simultaneous streams in RealNetworks and Microsoft formats.

NetStreamer is part of a new breed of easy-to-use products that allow webcasters to get up and running quickly. These machines are designed to eliminate the days of tweaking in desktop encoding software and the hours spent rendering the results. These days, it's realtime all the way, without the wait. Nann sees the quality continuing to ramp up in webcasting solutions, while broadband expands.

“The more recent web codecs deliver a far more pleasing result than they did a few years ago,” he says. “This improvement in quality has made webcasts more appealing to viewers. A few years ago, a lot of people considered most webcasts unwatchable simply because of the quality issue. And it wasn't long ago that we didn't have technical aspects of the formats, such as multiple bit-rate encoding. The increased penetration of broadband has been a big technical advancement.

“Meanwhile, the products for producing a webcast have improved exponentially. Even for non-realtime encoding, a lot of the advanced parameters and options for optimizing quality and compression that are available today in encoding packages just didn't exist not that long ago.”

Part of the excitement and convenience, Nann notes, comes from being able to use a webcast encoding unit as a standalone production machine. In the end, this allows video producers to focus on content rather than technical considerations.

“In terms of live webcasting, it wasn't long ago that features like logo and title insertion, combining live video with pre-recorded video, and other ‘traditional’ production features weren't available, or required the use of external processing to the incoming video signal,” Nann says. “Webcast producers had to use multiple separate software applications and tools to achieve functionality that's now available in single integrated solutions, greatly reducing complexity. A few years ago, technical limitations of webcasting dictated how a webcast was produced. While there are obviously still technical considerations specific to webcasting that producers have to take into account, we're starting to reach a point where the content can dictate how a webcast is produced, rather than technical considerations.”

So, what about content? What does it take to get users to tune in?

“A webcast of a national sporting event that doesn't really have any value-add over what's on TV will likely get only novelty interest,” Nann says.

“But a webcast of an event that's not nationally televised, or goes behind the scenes of what's on TV, will capture some attention.

“Where live web streaming is in high demand right now is for more regional applications. From a public standpoint, there's demand for webcasts of regional events, such as parades, municipal government meetings, and local sporting events. There's also a lot of demand for special-interest live webcasts — university convocations, education and training, and corporate events such as shareholder meetings.”

Encoding video on a desktop certainly gives more options for tweaking than running it through a standalone, rackmount unit. The tradeoff is that with more encoding quality you get less encoding speed.

“With enough CPU horsepower, almost anything that can be done in software can be done on-the-fly,” Nann says. “Realistically though, precise software processing currently has an edge in encoding quality because of the specific preprocessing that can be applied to the video being encoded.

“You could theoretically embed that same software functionality into hardware for on-the-fly encoding, but that's pretty limiting. Encoding formats are frequently upgraded [thus changing the nature of what preprocessing will be most effective], and using a software basis for on-the-fly encoding provides the most future flexibility. Today, it really amounts to a tradeoff between encoding speed and encoding quality. For many applications, the producer can't wait 10 hours for a software package like Media 100's Cleaner to squeeze an extra 10% of quality into the available bandwidth limits.”

For this reason, Nann says desktop encoding may not be a real solution in a deadline-driven broadcast environment. “Obviously, processing on the desktop isn't acceptable for live webcasts. And even encoding for later, on-demand viewing often has to be done in a more timely fashion. It's a productivity thing,” he says.

“Having the encoding done in realtime, even if it's just archived for later use rather than streamed live, means the producer can move on to his next encode rather than wait for the current one to finish. Precise software encoding times are long even for short-form pieces, and if you need to webcast a seminar or event that's an hour or longer, the rendering times become even more unacceptable.

“I'm not saying that on-the-fly encoding isn't of acceptable quality — it certainly is; the quality of today's on-the-fly encoders is great. Non-realtime software processing does have a degree of quality advantage, though. But the producer has to decide whether the lengthy encoding time to squeeze that extra little bit of quality with precise software encoding is worth sacrificing timeliness of delivery and productivity.”

Finally, I asked Mike what video producers should look for when selecting a webcasting solution. While file formats are certainly key, being able to cast multiple streams is pivotal.

“In short, as a producer you want to be able to reach the widest audience possible, and provide each viewer with the optimal quality for their particular viewing environment,” he says.

“That's just not possible with a single stream. The more simultaneous streams, the more viewers you can reach optimally. Make sure that the streams can be independently scaled in terms of resolution. Many of the advantages of multiple streams would be lost if they all had to be exactly the same size. Also, stream amount should be limited only by CPU power, not by a built-in, artificial limit of the unit.

The systems that don't impose any particular limit will be far more flexible and will scale up.”

As you search for a webcasting solution, bear in mind that there are organizations that specifically cater to this large section of the video market. From a video content developer standpoint, joining a group of knowledgeable producers in the webcasting business can help when guidance and recommendations are required.

Stop by the International Web-casting Association website at www.webcasters.org for information on how to join and get involved. Some of the benefits of IWA membership include being able to promote your webcasting events through the organization's website, posting on discussion boards, discounts on various conferences and products, as well as a monthly association newsletter. The group also provides grants to educational and nonprofit endeavors in video streaming, so it is a great way to get exposure if you are working on a video project of that nature.

Webcasting, as well as the Web itself, will hopefully go the way of electricity as an industry. You don't think about electricity, you just use it. The Web has certainly become a vital part of all of our lives, and the webcasting field will continue to develop stand-alone products that make producing a webcast as easy as flipping a few more switches in your studio or control room.

It's an exciting time to be a video producer and the efforts to make broadcasting over the Web even easier should be welcome news for video producers all around the world.

Frank McMahon is a media artist specializing in directing, editing, animation, and graphic design. He can be reached via his media company at www.fmstudio.com, or through the Portland Media Artists at www.mediaartist.com.

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