do you really need a separate App? I have the Fire stick and all I need to do is enable mirroring in the Fire stick settings and then when I open video on the phone, Screen Mirror is one of the share options. This is built into the os I believe.
Casting is much better than mirroring. When you can, you can still use your phone for anything but calls and it won't interfere with whatever you're casting. When you mirror, everything on your phone comes up on the TV
Anyone any idea how to cast a video in my Google Drive to my Chromecast?