Audio-only file playback "stutters" in IE 11 (using Flash audio):
https://en.wikipedia.org/wiki/File:Godzilla.ogg
https://en.wikipedia.org/wiki/File:Psalms_chord.ogg
Fine in Edge on same machine (using native Web Audio). Video files with audio are fine.
Double-check whether this is fixed in updated ogv.js or needs another tweak.