The sample custom receiver is now open source. Go to https://github.com/ooyala/chromecast-sample-receiver and open receiver_custom.html.
Customizable parameters are described in the code comments of the receiver. We will describe some ways you can customize the receiver here, but you are free to customize it in any way you like. You are not limited to the customizations shown here.
The custom receiver has the following components. You can customize them further as you wish. For more information on what you can customize with the custom receiver application, go to https://developers.google.com/cast/docs/custom_receiver.