HTML 5 will introduce new <audio> and <video> elements, for including these objects on a web page in a simple, standard way. Just as Netscape originally became successful due in part to the new <img> element, you can expect browser makers to quickly implement and take advantage of sound and video.
Currently, sound and video is only available using the general purpose <object> element and various non-standard techniques for each plug-in (QuickTime, Silverlight, Flash, etc).
The new elements have several benefits:
- accessible - to search crawlers, the visually impaired, etc
- standard user interface - for play, pause, etc
Possible uses of them include:
- Web page control of play, pause, fast forward, etc
- Web training videos with multiple choice tests on completion
- Video SVG filters (e.g. guassian blurs)
- Synchronized subtitles and sign language
Revealingly, both Flash and Silverlight don't neatly fit into this picture. They don't only enable video - they also handle vector graphics and html-like text. I suppose you could use the <video> element for Flash videos, and the <object> element for Flash graphics and text. But ideally you'd instead use html for text, and an element like <svg> or <vml> for vector graphics, in order to maintain the benefits above.
Once you've got normal html, <video>, <audio>, and <svg>, is every type of multimedia covered? No - there's still a need for interactive gaming user interfaces and 3D, for a start. But you're much further, and there's always the <object> element for missing pieces.