With HTML5 video and audio tags are here and ready for use to easily enhance your websites with audio and video. The tags are available in all major browsers now, except for Opera Mini (audio video). You even got popcorn.js to interact with the media, make you web pages react to the progress of a video and build cool new media enriched websites.
The major problem with HTML5 media though so far has been browser support for the different media formats/codecs. Support has gotten a lot better – not great, but better. At the time of this writing it seems like you only have to offer 2 different formats for audio and video to support a wide range of browsers.
Support mp3 and Ogg Vorbis – you can use other formats in place of ogg as well (and AAC in place of mp3).
Support H.264 (.mp4) + Theora (.ogv) or VP8 (WebM) should do the trick.
On a last not, if you want to convert video files you can use ffmpeg, e.g. for instance theora/.ogv to H.264/WebM:
ffmpeg -i demo.ogv -f mp4 demo.mp4
Hope that this helped 🙂