Signal-Android/app/src/main/res/layout/media_preview_exoplayer_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
    xmlns:tools="http://schemas.android.com/tools"
    tools:viewBindingIgnore="true"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.exoplayer2.ui.AspectRatioFrameLayout
        android:id="@+id/exo_content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center"/>

</FrameLayout>