case 1:
                    i = new Intent(A.this, B.class);
                    i.putExtra("channel","http://id=HBO");
                    startActivity(i);
                    break;

Bundle bundle = getIntent().getExtras();
    String channel = bundle.getString("channel");
    Uri uri = Uri.parse(channel);
    Intent intent = new Intent(Intent.ACTION_VIEW, uri);
    intent.setDataAndType(uri, "video/mp4");
    startActivity(intent);

@Override
public void onBackPressed() {
    if (interstitial.isLoaded()) {
        interstitial.show();
    }
    super.onBackPressed();
}