Fire TV instructions:
On your FireTV, Download AllCast Receiver for Fire TV and start the application
No setup necessary!
Download AllCast Receiver from the Chrome web store and start the application
Can't find the Receiver? Adjust your firewall settings to allow UDP/TCP ports 53515.
Android to Android mirroring:
Download AllCast Receiver from the Google Play store and start the application
Screen Recording also supports recording to GIF.