I have WordPress 3.5.1 and upgraded MediaElement.js to 2.10.3, which is use in the sermon browser plugin 0.45.4. After upgrade the Audio Controls (play, length, volume, progress of buffer and audio) did not appear in Chrome or IE9. Instead a black bar with a large bold word DOWNLOAD displayed. Clicking on the black bar starts a full screen play of the audio where the audio controls are visible (working and correct). My problem is that it looks ugly and most people are not going to know to click on the black bar.
I deleted MediaElement.js and uploaded version 2.9.1, activated it and everything works fine.
I found this thread, which didn't seem resolved at the time (and I urgently wanted my site working again):
Does anyone have a fix to get MediaElement.js 2.10.3 working with WordPress 3.5.1 (and Sermon Browser 0.45.4)?