Cast app, android cast app does need both sender and receiver?

I just want to know is that. For creating the cast application we have to develop or provide both functionality sender and receiver. I mean as the user downloads the Cast app in mobile, user also have to download it in the LED. Now the mobile becomes the sender and the LED tv app becomes the receiver.

Is this is the way it all works??

The Google Cast SDK enables you to extend your Android, iOS, or Web app to direct its streaming video and audio to a TV or sound system. Your app becomes the remote control to play, pause, seek, rewind, stop, and otherwise control the media.

The scenario you are asking above is one of the feature we support called "Cast connect" https://developers.google.com/cast/docs/android_tv_receiver which allows users to launch the Android TV application and acts as a receiver.

Please read the document for more information on Senders and receivers:

1. Get Started - https://developers.google.com/cast/docs/get-started
2. Sender - https://developers.google.com/cast/docs/android_sender
3. Web Receiver - https://developers.google.com/cast/docs/web_receiver
4. Android TV receiver(Cast Connect) - https://developers.google.com/cast/docs/web_receiver