Originally Posted by
broadwayblue
Don't know about how they play on Chromecast, but you can play MKV or other local files in Chrome...a shortcut is to press Ctrl + O and navigate to the file on your local or network device.
On my win7 pc with latest chrome, mp4 plays, but not avi or mkv.
mp4 and mkv are container formats, so it might depend on the underlying codec.