Signal-Android/app/src/main/res/layout/giphy_mp4.xml

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

    <com.google.android.exoplayer2.ui.AspectRatioFrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_margin="3dp">

        <com.google.android.material.imageview.ShapeableImageView
            android:id="@+id/still_image"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="fitXY"
            app:shapeAppearanceOverlay="@style/Signal.ShapeOverlay.Rounded" />

    </com.google.android.exoplayer2.ui.AspectRatioFrameLayout>
</FrameLayout>