player2.kt

@Composable
fun VideoPlayer() {
    // This is the official way to access current context from Composable functions
    val context = ContextAmbient.current

    // Do not recreate the player everytime this Composable commits
    val exoPlayer = remember {
        SimpleExoPlayer.Builder(context).build().apply {
            val dataSourceFactory: DataSource.Factory = DefaultDataSourceFactory(context,
                Util.getUserAgent(context, context.packageName))

            val source = ProgressiveMediaSource.Factory(dataSourceFactory)
                .createMediaSource(Uri.parse(
                    // Big Buck Bunny from Blender Project
                    "https://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4"
                ))

            this.prepare(source)
        }
    }
    
    // Gateway to traditional Android Views
    AndroidView(
        viewBlock = { context ->
            PlayerView(context).apply {
                player = exoPlayer
                playWhenReady = true
            }
        }
    )
}

I had to change viewBlock to factory and playWhenReady is not a member. But it could be my version of the libraries (compose_version = 1.0.0-beta02). And I'm just starting to understand compose, so expect some misunderstandings.

Yes you are right, this was written for beta01 and an older version of ExoPlayer.