subtitle not working

I am using wordpress 3.7.1 and use buildin mediaelements.js video support. I want to ask does this version support subtitles?

I have a video in this page with English and Japanese subtitles

http://www.enterpr1se.info/2013/06/gordon-music-station-onslaught-of-locusts/

Here is the code

[video width="1920" height="1080" mp4="http://www.enterpr1se.info/wp-content/uploads/2013/06/Locust-attack.mp4" captions="http://www.enterpr1se.info/wp-content/uploads/2013/06/Locust_attack_jap.srt" captions="http://www.enterpr1se.info/wp-content/uploads/2013/06/Locust_attack_eng.srt"][/video]

But there’s no control for captions.

Is there anything I missed? Thanks

http://wordpress.org/plugins/media-element-html5-video-and-audio-player/