All new videos uploaded to YouTube are now transcoded into WebM. WebM is an open media file format for video and audio on the web. Its openness allows anyone to improve the format and its integrations, resulting in a better experience for you in the long-term. YouTube hopes to reduce the technical incompatibilities that prevent you from accessing video while improving the overall online video landscape.
Transcoding to WebM
Transcoding all new video uploads into WebM is an important first step, and YouTube also working to transcode our entire video catalog to WebM. Given the massive size of the catalog - nearly 6 years of video is uploaded to YouTube every day - this is quite the undertaking.
So far YouTube already transcoded videos that make up 99% of views on the site or nearly 30% of all videos into WebM. They are focusing first on the most viewed videos on the site, and made great progress here through there cloud-based video processing infrastructure that maximizes the efficiency of processing and transcoding without stopping.
How it works
At busy upload times, YouTube's processing power is dedicated to new uploads, and at less busy times, their cloud will automatically switch some of our processing to encode older videos into WebM.
In keeping with their goal of making videos universally accessible, YouTube will continue to support H.264 as an important codec for video on YouTube. They are also committed to continuing to develop the HTML5 video player which was announced last year.