Herald uses the Brightcove player which can deliver Flash or HTML5=H264.
Firefox on my Mac desktop prompts for installation of the Flash plugin which indicates either Brightcove is not smart enough to detect h264 support for FF on mac or FF does not have this support.
Safari plays this content using h264 no problems.
Which Android browsers will play the Herald videos in h264?
Before you say that [your browser] plays Herald videos in h264 - please visit the Flash player test page to see if Flash is installed on your device - my guess is Brightcove will use Flash by default therefore making success false where Flash is installed.