YouTube videos are now served in WebM format as reported by James Zern, Software Engineer, on the company blog. Now the vide site is transcoding all new videos into the WebM format, as well as other supported formats, which include MPEG4, 3GPP, MOV, AVI, MPEGPS, WMV, and FLV.

In the announcement, YouTube says they are working to transcode the rest of the YouTube catalog.

“Given the massive size of our catalog – nearly 6 years of video is uploaded to YouTube every day – this is quite the undertaking,” says software engineer Jmes Zern. “So far we’ve already transcoded videos that make up 99% of views on the site or nearly 30% of all videos into WebM. We’re focusing first on the most viewed videos on the site, and we’ve made great progress here through our cloud-based video processing infrastructure that maximizes the efficiency of processing and transcoding without stopping.”