When I upload mp4 files they are not getting picked up to be transcoded. The trigger for transcoding is the mime type (wp_*_posts.post_mime_type must begin with ‘video/’. The mime type for mp4 is defined correctly in wp-includes/functions.php: get_allowed_mime_types():
‘mp4|m4v’ => ‘video/mp4’,

But when I upload an MP4 file the mime type is loaded as ‘application/octet stream’ and transcoding is not initiated (and I can’t use shortcodes for embedding the mp4.

If I add a plugin filter to add the mime type to the list again, the mime-type is set correctly on upload and transcoding is initiated for mp4 files. Strange.

function add_new_mime_types($mimes=”)
return $mimes;

It does not appear to be server setup related (Apache, etc) since a simple filter fixes things. Has anyone else seen this behavior? By the way, the simple filter above is a great way to add additional file types to encoding (raw DV files, for example) if you want to provide more transcoding options for uploaded files.