On the production side, as long as you have a Real or Windows Media Services server running and a Web server, you're set. The presenter doesn't have to make many decisions on streaming settings, and the webcasting software automates the stream distribution. Once our IIS and streaming services were set up, we didn't need to touch them again. You can specify codecs and bit rate on a per-presentation basis: The Accordent and Sonic Foundry products let you save a stream in multiple bit rates, allowing for high- and low-bandwidth presentations. Actual bandwidth will depend on the video-encoding settings--PowerPoint slides and interactive content displays are generally not as bandwidth-intensive as video.
We used a Mini-DV camcorder, which can output live A/V, to capture video and audio. Our participants support any video or audio system your capture card supports: a house sound system for audio, for instance, or a television feed or VHS/DVD player for video.
The three vendors implement PowerPoint capture differently. Communicast requires you to upload the slides first, have them converted to image files, and then display and cycle through slides inside the Communicast presenter. If you're presenting to an in-person audience as well as webcasting, you must have a webcasting director cycling the webcast slides as the presenter does the same. Accordent's PresenterPro requires you to import slides before the presentation. You can let a webcast director cycle through slides, or use a PowerPoint add-in that cycles the webcast slide when the presenter cycles his. In either case, the webcast slides will be synchronized with the presentation. Mediasite has a VGA capture card. You can plug a laptop into the VGA port, or use a VGA splitter to use Mediasite and an overhead projector simultaneously. Mediasite recognizes and captures the slides automatically as they cycle, so there is no need to upload or convert slides before the event. We liked this best.