Audio and video on the Internet

摘要

As Doctor Johnson said ...When it comes to dogs walking on their hind legs you have to marvel at the ingenuity of audio and video on the Internet. As with those legendary canines in Dr Johnson's observation the wonder is not how well they do it but that they can do it at all! I'm not referring to so-called broadband of course. Give anyone a few megabits of data and you would expect some kind of video to be possible. But down in the land of the dial-up modem and the mobile telephone there are no such riches to be found and a lot of ingenuity is needed to make video possible: and sometimes it is a struggle to 'merely' carry audio. One of the ironies in the history of multimedia is the way developments in delivery media change, and as a result we have to start over again with the quality of video we can use. I could say it was something of a roller coaster ride, but that implies a level of speed and excitement. So I will refer to it as something of a see-saw going up and down repeatedly. When videodisks were introduced in the late 1970s and multimedia was known as interactive video, we had a reasonably high quality source of video and audio at our command. The video channel was full bandwidth PAL or NTSC and could be accessed frame by frame.