The debate between using Adobe Flash or HTML5 for online videos could be winding down, but the war among different video formats is heating up.

A whopping 63 percent of all videos on the Web are now HTML5-compatible, compared to only 10 percent just a year ago, according to video-sharing site Mefeedia. Instead of relying solely on Flash to display their videos, many more Web sites are adopting video formats that can run directly in HTML5-compatible browsers.

The majority of the sites uncovered by Mefeedia are using H.264, the most common video format since it's also compatible for playback using Flash. Google's VP8, or WebM, video codec is second on the popularity charts, followed by Ogg, aka Ogg Theora.

With Apple's no-Flash requirement, Mefeedia says that sites such as YouTube, Daily Motion, Blip TV, and Vimeo are among those striving to support video on iOS devices. Specifically, mobile devices now represent 5 percent of the traffic to Mefeedia's site, up from 1 percent a year ago.

Although HTML5 has shot up in popularity as an alternative to Flash, the array of video codes supported within HTML5 are themselves battling for dominance. H.264 may currently be the most common among the three on the Web, but lately it's divided different companies against each other.

Google recently dropped a bombshell by announcing it would no longer support H.264 in its Chrome browser and would instead push for its own WebM codec. Many in the industry decried the decision, but Google justified it by saying that H.264 carries with it some hefty royalty fees, while WebM is open source. Apple and Microsoft are members of a patent pool called MPEG-LA that actually licenses the code for H.264, while Mozilla and Opera are stuck paying the licensing fees.

The debate over HTML5 video formats is one that could be with us for awhile. This means that for the time being, many Web sites will need to continue to support more than one format for their videos. In Mefeedia's eyes, "Web video is maturing and becoming more complex."

To compile its findings, Mefeedia analyzed the videos indexed on its site (around 30 million from more than 30,000 video sites). The index includes videos from such content partners as Hulu, CBS, and ABC as well as videos from YouTube, Vimeo, and DailyMotion. Mefeedia specifically looked at videos that can play within HTML5's "video" tag, which in most cases means videos encoded using H.264.