Interestingly you can deliver vorbis audio natively, via Java, and via Flash 10 (see https://launchpad.net/fogg), so for audio you only need one format for 99% coverage.
And despite that fact no-one talks about it, Vorbis is actually state of the art, competitive with both AAC and AAC-HE at their respective sweet spots but without the problem of AAC-HE degrading badly on decoders that only support AAC (e.g. Apple stuff).
(Vorbis is also patent clear, used widely by big companies, well supported in hardware, and music seems to have moved away from DRM so it basically trumps every objection made to Theora.)
For video, though people like to talk about H.264 as if it was a single codec, it's actually a family or toolkit designed to go from web video on small portable devices up to Hollywood Blue-Ray on 100" projector televisions. (I've seen people seriously claim Theora is unsuitable as a standard web codec because it doesn't handle film grain as well as H.264. Film grain!) Unfortunately you can't encode one H.264 stream that'll work on everything as encode and decode complexity ramp up harshly as you move up the profiles.
I predict that since the iPhone (and similar) is the hot platform right now, and it doesn't have Flash, you'll see a lot of places following Kroc Camen's lead and encoding twice, one for Theora and one for iPhone compatible H.264 which will then be deliver by Flash for non-Theora platforms.
The kicker here is that iPhone compatible H.264 is far from the best possible quality you could squeeze out for desktop use, but is more than good enough for most folks so the two videos will be basically equivalent in quality.
And despite that fact no-one talks about it, Vorbis is actually state of the art, competitive with both AAC and AAC-HE at their respective sweet spots but without the problem of AAC-HE degrading badly on decoders that only support AAC (e.g. Apple stuff).
(Vorbis is also patent clear, used widely by big companies, well supported in hardware, and music seems to have moved away from DRM so it basically trumps every objection made to Theora.)
For video, though people like to talk about H.264 as if it was a single codec, it's actually a family or toolkit designed to go from web video on small portable devices up to Hollywood Blue-Ray on 100" projector televisions. (I've seen people seriously claim Theora is unsuitable as a standard web codec because it doesn't handle film grain as well as H.264. Film grain!) Unfortunately you can't encode one H.264 stream that'll work on everything as encode and decode complexity ramp up harshly as you move up the profiles.
I predict that since the iPhone (and similar) is the hot platform right now, and it doesn't have Flash, you'll see a lot of places following Kroc Camen's lead and encoding twice, one for Theora and one for iPhone compatible H.264 which will then be deliver by Flash for non-Theora platforms.
http://camendesign.com/code/video_for_everybody
The kicker here is that iPhone compatible H.264 is far from the best possible quality you could squeeze out for desktop use, but is more than good enough for most folks so the two videos will be basically equivalent in quality.