I found this really useful article when working with uploading videos on WordPress. Read more
Browser Support
So which of these file types do you need for your website? Well ideally all 3 would be great as they provide the full support spectrum. Yet this isn’t realistic, and in fact, you can cover all the bases with only two of them. Here is a breakdown of what works for each browser:
Mozilla Firefox – WebM, Ogg
Google Chrome – WebM, Ogg
Opera – WebM, Ogg
Safari – MP4
Internet Explorer 9 – MP4
Internet Explorer 6-8 – No HTML5, Flash Only!
If you remember, earlier I mentioned that most flash video players will support MP4 files as long as they’re encoded in H.264. As such, each of these browsers will embed MP4+Flash as a final resort. This means you only need to create two different video formats to support all browsers. MP4 for Safari/IE9 and a choice between WebM or Ogg for the rest.
In my opinion I highly recommend sticking with the WebM format. It has some big names behind the project (namely Google) and has gained a lot of traction in the HTML5 community. Ogg/Ogv will be supported but will most likely lose out in popularity to WebM’s smaller file sizes. You can read a related piece on the future of video on the web written by Sean Golliher.
Mobile Device Support
This topic is still highly debated since the mobile industry is so young. Apple came out with support for MP4 on Mac and iOS devices. This means you can natively stream .mp4 video files on your iPad, iPhone, or iPod Touch in the standard video UI. This covers a lot of the market share.
Recently Android devices were having a difficult time getting to this same level of support. However Google has finally adopted .mp4 web streaming which now capitalizes on nearly all mobile users. And since Flash isn’t an option here MP4 is the best solution available. This is why you want to embed the .mp4 code first so that iOS devices can recognize the file immediately.