There's now an easy way to stream any video file on your computer or network-connected device through Google Chromecast and to your television. It's called Videostream.
Videostream is a web app available on the Chrome Web Store. You can install it on your Chrome browser or Chromebook. And once you do, you can start playing your own locally stored movies and videos. Some Chrome web apps, such as Plex, require that you do complicated things like set up a media server to stream, but this app is simple. It recently added support for any file, including mkv, avi, mp4, etc, and has a remote control app for your mobile device.
So, how does Videostream work? Install the web app. Then, when the app opens in your browser, click the orange "Select a movie to play" button. You'll then be able to choose a video file stored on your computer or even a hard drive on your network. Once you select the file, go to your Chromecast extension at the top-right of the browser and select your Google Chromecast. If you don't have the Chromecast extension, download it from the Chrome Web Store.
READ: Google Chromecast review
You'll need to make sure your Chromecast is plugged into a television that's turned on, naturally, and that your input is switched to Chromecast. And voila! Your movie should stream instantly from your computer to your big screen. You can even pay the premium Videostream subscription, which costs just $1.49 a year, to make a video playlist and then control what's playing on that playlist with the Videostream Android app.
With Videostream, you can cast home videos or movies you've download from your computer to a television. You can cast any type of video you want, in fact. It's a really handy app that anyone with a Chromecast should immediately download.