Wired:

The video encoding is handled by the new video platform Yahoo has been developing. The platform is a transcoder that converts any uploaded video to H.264 format, and it’s accessible through an API. It’s only available internally right now, and Yahoo will continue to expand its use across the rest of its video-heavy sites like Music, News and Sports. The company says it plans on eventually opening up the video transcoder platform for use by independent publishers and developers.