# How to configure a different stream to Chromecast on Android

Some streaming setups require you to cast a different stream to a Chromecast Receiver device than the one playing on a Chromecast Receiver device. For example, if you're playing HLS + FairPlay DRM on your iOS application, you need to cast a different source with DASH + Widevine DRM to your Chromecast application, because Chromecast applications aren't able to support FairPlay.

You can achieve this use case with the ChromecastConnection API.

## ChromecastConnection API

The ChromecastConnection API allows you to implement callbacks related to Chromecast playback. To achieve the described use case you can use the `onStart` (i.e. the start of a Chromecast session) to set a new stream, and `onStop` (i.e. the end of a Chromecast session) to (re)set your previous stream.

You may also be interested in `onJoin` (i.e. joining an existing Chromecast session with a new device) or `onLeave` (i.e. leaving an existing Chromecast session on a device).

The snippet below has two [sources](https://docs-preview.optiview.dolby.com/pr-861/theoplayer/v11/api-reference/android/com/theoplayer/android/api/source/SourceDescription.Builder):

1. `senderSource` is intended for playback on your sender device (i.e. your Android app)
2. `chromecastSource` is intended for playback on your Chromecast application

The [`setConnectionCallback`](https://docs-preview.optiview.dolby.com/pr-861/theoplayer/v11/api-reference/android/com/theoplayer/android/api/cast/chromecast/Chromecast#setConnectionCallback-com.theoplayer.android.api.cast.chromecast.ChromecastConnectionCallback-) method on the [`Chromecast`](https://docs-preview.optiview.dolby.com/pr-861/theoplayer/v11/api-reference/android/com/theoplayer/android/api/cast/chromecast/Chromecast) instance is used to:

1. Set the `chromecastSource` when Chromecast playback starts through the `onStart` callback.
2. Revert to the `senderSource` when Chromecast playback stops through the `onStop` callback.

```kotlin
val senderSource = SourceDescription.Builder(
    TypedSource.Builder("https://cdn.theoplayer.com/video/elephants-dream/playlist.m3u8")
        .type(SourceType.HLS)
        .build()
).build()
val chromecastSource = SourceDescription.Builder(
    TypedSource.Builder("https://cdn.theoplayer.com/video/big_buck_bunny/big_buck_bunny_metadata.m3u8")
        .type(SourceType.HLS)
        .build()
).build()

val player = theoPlayerView.player
val chromecast = theoPlayerView.cast.chromecast

player.source = senderSource
chromecast.setConnectionCallback(object : ChromecastConnectionCallback {
    override fun onStart(sourceDescription: SourceDescription?): SourceDescription = chromecastSource

    override fun onStop(sourceDescription: SourceDescription?): SourceDescription = senderSource

    override fun onJoin(sourceDescription: SourceDescription?): SourceDescription? = sourceDescription

    override fun onLeave(sourceDescription: SourceDescription?): SourceDescription? = sourceDescription
})
```

The `onJoin` and `onLeave` implementations in the above snippet adhere to the default behavior.