The HTML5 video tag obviously requires a standardised codec in order to achieve full interoperability, but the browser makers have been unable to reach a consensus about which codec to implement in their browsers, HTML5 specification editor Ian Hickson writes.
Google implements both Ogg Theora and H.264 in Chrome, but sadly, the expensive licensing costs for H.264 prevents other Chromium distributors from implementing H.264. Google also said that Ogg Theora's quality-per-bit is not yet good enough for the volume handled by YouTube. Mozilla implements Ogg Theora, but not H.264 due to not being able to provide a license for downstream distributors. Opera will most likely implement Ogg Theora as well, but won't implement H.264 due to its prohibitive licensing costs.
This means that three of the major browser makers standardise on Ogg Theora. While Theora may not be up to par with H.264 yet, the fact that so many browser makers decided to implement it may speed up its development.
So, this leaves only Apple and Microsoft. Apple has said that they will not implement Ogg Theora support in QuickTime (what Safari uses), citing a lack of hardware support and an uncertain patent situation. This seems like a cop-out on Apple's end - the other browser makers seem to have no problems with Theora's patent situation. Microsoft, by the way, hasn't said anything about this situation at all - it's not even known when or if they're going to implement the video tag at all.
According to Hickson, this situation could go either of two ways (or both):
- Ogg Theora encoders continue to improve. Off-the-shelf hardware Ogg Theora decoder chips become available. Google ships support for the codec for long enough without getting sued that Apple's concern regarding submarine patents is reduced. => Theora becomes the de facto codec for the Web.
- The remaining H.264 baseline patents owned by companies who are not willing to license them royalty-free expire, leading to H.264 support being available without license fees. => H.264 becomes the de facto codec for the Web.
As for audio, no common codec has been required, because there are so many more available. Audio is also of less importance, so Hickson argues that we should just wait and see if any common codec surfaces in the future, at which point it could be made a requirement.