Reported upstream. `2.14.0` is necessary for playing `m4a` files properly. `2.14.0` with the offending pull request is unusable in Chrome. See #27582. Built from https://develop.svn.wordpress.org/trunk@27853 git-svn-id: http://core.svn.wordpress.org/trunk@27684 1a063a9b-81f0-0310-95a4-ce76da25c4cd