Is mv4 video supported by all systems/browsers?

Question

I'm having problems with Firefox (39) and mp4 video in the videojs player. The mp4s are created in Handbrake, from .movs. Problem is in some files there's no audio in playback off my server in Firefox. The audio is "there" - it plays normally in Firefox off the C drive.

On a hunch, I converted the .movs to .m4v and discover the audio plays in Firefox off the server. Works in Chrome and IE-11 too (all on Windows 7). iOS no problem. I read here that mp4 and m4v "are the exact same file, the only difference is the extension", so why one is delivering audio in FF and one not I have no idea.

Before switching the files on the server,.,.. might m4v be not supported by other browsers or by other operating systems?

Answer 1

This is likely https://bugzilla.mozilla.org/show_bug.cgi?id=875573

Make sure your server sets the mime type for m4v to video/mp4 instead of video/x-m4v.