There's not enough space for a pop-up volume control when the applet is in audio-only mode.

Hm, can't it pop up as a separate AWT window or something?

*the terror of java UIs*

With "untrusted java applet" written across it? That'd be a classy volume control.

TimedMediaHandler was deployed at the beginning of November 2012, see
https://www.mediawiki.org/wiki/TimedMediaHandler and http://blog.wikimedia.org/2012/11/08/introducing-wikipedias-new-html5-video-player/ for more information.
It is based on HTML5 and supports closed captions, timed text, WebM, etc.

This bug report was reported about "Cortado". With TimedMediaHandler being in place, Cortado is now ONLY used as a fallback for web browsers that do not support any of the video codecs we offer but have Java installed. This currently is Apple Safari without XiphQt installed, or Microsoft Internet Explorer with Java applet installed.

Please add a comment here in case that you still face the problem described (now with Cortado inside of TimedMediaHandler) if using one of the browsers mentioned above. In that case, this report should be moved to product="MediaWiki extensions" and component="TimedMediaHandler" in this bug tracker.

Issues that also happen with Cortado without TimedMediaHandler should be reported to https://trac.xiph.org/ instead.

Wikimedia itself is currently not actively working on Cortado.
If you are still interested in seeing this, please check the existing upstream tickets at https://trac.xiph.org/query?component=Cortado&group=component&col=id&col=summary&col=status&col=owner&col=type&col=priority&col=milestone&order=priority and if no ticket exists yet for this request, please create one in upstream.

Also see comment 4 in this report for more explanation which way Wikimedia Multimedia currently takes. Closing as WONTFIX for Wikimedia itself.