The proportion of online videos compatible with HTML5 has increased from 10% to 63% in the past year, according to video-tracking site MeFeedia.
A study by MeFeedia of 30 million video clips from 30,000 video sources found the rise in the number offering HTML 5 compatibility has been rapid.
In January 2010, only 10% were HTML 5-compatible using the H.264 standard, but that jumped to 26% in May, 54% in June and 63% in February 2011.
The H.264 format appears set to challenge Flash as the dominant format for online video producers.
In an open letter, Apple's chief executive Steve Jobs listed the reasons for not supporting flash in the company mobile device products.
Steve Jobs said Flash was unreliable, not secure, had an impact on mobile battery life and was not designed for touchscreens.
YouTube, Microsoft and others have joined Apple in supporting H.264 as a replacement for Flash.