MBONE: Multicasting Tomorrow's Internet
MIME is a specification that offers a way to interchange text in languages that have different character sets and exchange multimedia e-mail among various computer systems. In addition to plain old ASCII text, MIME messages can include other character sets, images and sounds, PostScript files, pointers to FTPable files, and more.
For more information about MIME, read the comp.mail.mime FAQ, which is available on the Internet at ftp://rtfm.mit.edu/pub/usenet-by-group/news.answers/mail/mime-faq/ and at http://www.cis.ohio-state.edu/text/faq/usenet/mail/mime-faq/top.html.
Not all e-mail clients can handle MIME, although an increasing number of them do. We use Eudora (for the Mac and Windows) and TCP/Connect II (for the Macintosh) for our MIME e-mail needs.
Using VideoMail, you can digitize yourself (using audio and video, or just audio, depending on the hardware attached to your Mac), enter an e-mail address, and watch VideoMail encode the multimedia message and fire it off to an associate in just a few seconds. The recipient receives e-mail with an encoded attachment a QuickTime movie of your face and voice. (See Figure 2-14.)
VideoMail works great for short messages, but you're likely to annoy your friends if you send them a 10-minute video of yourself with a cat on your head. As with all other multimedia, sending audio and video messages with VideoMail takes a good chunk of bandwidth about 7 Kbps for audio only and 30 Kbps for audio and video. The program's author recommends keeping AV messages to 15 seconds or less, and audio-only messages to under 45 seconds. A 15-second VideoMail message with audio and video can take about 4 minutes to download at 14.4 Kbps. Many users would agree that although that time could be much faster, it approaches an acceptable download time for a message of that length.
VideoMail is not an end-all e-mail program. It was designed to be a simple, send-only multimedia mailer and is a fine complement to a full-featured e-mail program such as Eudora. Perhaps soon, full-featured mail programs will include the ability to capture and send audio and video without the help of a separate program such as VideoMail.
Figure 2-14: VideoMail screenshot.
For more information about VideoMail, check out http://www.spyglass.com/~dtrinka/videomail.html.
But electronic mail doesn't occur in real time; it doesn't matter terribly whether the message you send is received in ten seconds or two minutes. So, with multimedia e-mail, the information can travel at a more leisurely pace than it can with real-time applications. If packets arrive out of order, they can be reassembled in sequence with no loss of continuity. When your e-mail program barks that mail has arrived, you'll receive a clear message, complete with video and audio.
Some people say that in the Internet's middle future, your service provider's charges may be based on how much information you send and how quickly you want that data to arrive, rather than on how long you're online. Under this scheme, real-time audio and video, which use a large amount of bandwidth and require fast distribution to the recipient, would be expensive. On the other hand, a multimedia e-mail message would cost less to send because although it might use the same amount of bandwidth, data could be sent at a lower priority because precise timing is not critical.
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