packages/SystemUI/res/layout/qs_media_panel.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2019 The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License
  -->

<!-- Layout for media controls inside QSPanel carousel -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/qs_media_controls"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:gravity="center_horizontal|fill_vertical"
    android:padding="16dp"
    android:background="@drawable/qs_media_background"
    >

    <!-- Header section -->
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="16dp"
    >

        <ImageView
            android:id="@+id/album_art"
            android:layout_width="@dimen/qs_media_album_size"
            android:layout_height="@dimen/qs_media_album_size"
            android:layout_marginRight="16dp"
            android:layout_weight="0"
        />

        <LinearLayout
            android:orientation="vertical"
            android:layout_width="0dp"
            android:layout_height="@dimen/qs_media_album_size"
            android:layout_weight="1"
        >
            <LinearLayout
                android:orientation="horizontal"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center"
            >
                <com.android.internal.widget.CachingIconView
                    android:id="@+id/icon"
                    android:layout_width="16dp"
                    android:layout_height="16dp"
                    android:layout_marginEnd="5dp"
                />
                <TextView
                    android:id="@+id/app_name"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textSize="14sp"
                    android:singleLine="true"
                />
            </LinearLayout>

            <!-- Song name -->
            <TextView
                android:id="@+id/header_title"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:singleLine="true"
                android:fontFamily="@*android:string/config_headlineFontFamilyMedium"
                android:textSize="18sp"
                android:paddingBottom="6dp"
                android:gravity="center"/>

            <!-- Artist name -->
            <TextView
                android:id="@+id/header_artist"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:fontFamily="@*android:string/config_bodyFontFamily"
                android:textSize="14sp"
                android:singleLine="true"
            />
        </LinearLayout>

        <!-- Output chip -->
        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:visibility="gone"
            android:paddingTop="6dp"
            android:paddingBottom="6dp"
            android:paddingLeft="12dp"
            android:paddingRight="12dp"
            android:gravity="center"
            android:id="@+id/media_seamless"
            android:background="@*android:drawable/media_seamless_background"
            android:layout_weight="1"
        >
            <ImageView
                android:layout_width="@dimen/qs_seamless_icon_size"
                android:layout_height="@dimen/qs_seamless_icon_size"
                android:src="@*android:drawable/ic_media_seamless"
                android:layout_marginRight="8dp"
                android:id="@+id/media_seamless_image"
            />
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:fontFamily="@*android:string/config_bodyFontFamily"
                android:text="@*android:string/ext_media_seamless_action"
                android:textSize="14sp"
                android:id="@+id/media_seamless_text"
                android:singleLine="true"
            />
        </LinearLayout>
    </LinearLayout>

    <!-- Controls -->
    <LinearLayout
        android:id="@+id/media_actions"
        android:orientation="horizontal"
        android:layoutDirection="ltr"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        >
        <ImageButton
            style="@android:style/Widget.Material.Button.Borderless.Small"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            android:gravity="center"
            android:visibility="gone"
            android:id="@+id/action0"
        />
        <ImageButton
            style="@android:style/Widget.Material.Button.Borderless.Small"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            android:gravity="center"
            android:visibility="gone"
            android:id="@+id/action1"
        />
        <ImageButton
            style="@android:style/Widget.Material.Button.Borderless.Small"
            android:layout_width="52dp"
            android:layout_height="52dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            android:gravity="center"
            android:visibility="gone"
            android:id="@+id/action2"
        />
        <ImageButton
            style="@android:style/Widget.Material.Button.Borderless.Small"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            android:gravity="center"
            android:visibility="gone"
            android:id="@+id/action3"
        />
        <ImageButton
            style="@android:style/Widget.Material.Button.Borderless.Small"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginStart="8dp"
            android:layout_marginEnd="8dp"
            android:gravity="center"
            android:visibility="gone"
            android:id="@+id/action4"
        />
    </LinearLayout>
</LinearLayout>