Sorenson Broadcaster

Window into Streaming   Sorenson Broadcaster 1.0's single window offers extensive controls.

Apple's QuickTime 4.0 is the first QuickTime version to permit streaming of live content, such as radio or television feeds, convention speeches, and conferences. But while QuickTime Streaming Server can dish out live streams, it can't encode them. In broadcasting terms, QuickTime Streaming Server is merely a transmitter; it needs an incoming signal to beam out.

And that's where Sorenson Broadcaster 1.0 beams in–it lets you compress live audio and video signals into QuickTime streams. It's a versatile, well-designed tool, although the first version has a few rough edges and abysmal documentation.

Sorenson recommends running Broadcaster on a Power Mac G3, but you may be able to get away with a less powerful machine. We did most of our testing on a 400MHz G3, but we also successfully encoded 28.8-Kbps voice and music streams using an elderly Power Mac 7600/132. Regardless of your Mac's configuration, you don't need additional hardware to encode audio-only content: just plug your audio source into your Mac's input jack. To encode video, you need a Broadcaster-compatible capture card–a list of qualified cards is available on Sorenson's Web site.

A key part of streaming involves choosing compression settings appropriate to your content and to your audience's connection speeds. Sorenson Broadcaster's presets make this job a breeze, and a Customize button lets you tweak settings. After choosing compression settings, you specify the name of the broadcast as well as copyright information. Then you enter the Internet Protocol (IP) address of the QuickTime Streaming Server you'll be using to replicate the stream for listeners.

If your audience is connected to a local area network rather than the Internet, Sorenson Broadcaster offers a multicast mode. Multicasting uses network bandwidth efficiently by letting all users on your network "tune in" to one stream. And multicasting doesn't require QuickTime Streaming Server–all you need is Sorenson Broadcaster.

Sorenson Broadcaster can also archive a live stream to disk. This lets you save a live event for subsequent on-demand delivery using QuickTime Streaming Server. You can also archive live content without actually streaming it.

Before you can begin streaming, you have to announce the broadcast. This involves exporting, via Sorenson Broadcaster, a QuickTime movie containing URL and compression information, which your audience's QuickTime Players use to connect to the live stream.

If you're streaming over the Internet, you need to create a reference movie , stored on QuickTime Streaming Server, that points to the live stream. It's a simple process–or at least it would be if it were accurately documented. Sorenson Broadcaster's documentation is light on details and downright wrong in many places.

Sorenson Broadcaster has a few minor flaws. It lets you enter invalid IP addresses, for example, and it can crash if you enter some values incorrectly. But by and large, version 1.0 is a fine effort. If you're doing live QuickTime streaming, it's the only encoding tool you need.

February 2000 page: 50