YouTube Software Engineer John Harding today explained that the video site was still closely tied to Flash. While the site is "excited" about HTML5 and is using it for most videos in its optional player and mobile devices, many of the site's features still need Adobe's plugin to work well or to work at all. At a minimum, embedding needs the option as videos otherwise can't port over their ads, annotations or notes.
Many of the secondary features considered important to YouTube also need Flash to work. As HTML5 just provides direct access to the video, it can't dynamically adjust the buffer or the bitrate of the video to reflect the quality of service or the sheer load on YouTube's servers. The new web standard can't yet fully address microphone and webcams, doesn't always elegantly scale to full screen, and sometimes has trouble with content showing over top.
The recently introduced YouTube movie rental service also won't work as it needs copy protection due to studio requests.
Harding was emphatic that HTML5 was making "good progress" and that some issues like scaling were being addressed, but he warned that for now there were too many issues on both the creation and playback sides to ignore. Standards would play a part: YouTube has had to fork its video to support both H.264, which Apple and Microsoft are endorsing alongside Google, and the WebM standard Google created to help Chrome, Firefox and other browsers use a patent-free format. Splintering support makes it difficult to advance video technology.
WebM may not help Google's video development, as the MPEG-LA group and members like Apple have warned of patent issues that might not be addressed simply by claiming the format is royalty-free.