androidx/media/MediaPlayer2.java

/*
 * Copyright 2018 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.
 */

package androidx.media;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.annotation.TargetApi;
import android.graphics.SurfaceTexture;
import android.media.AudioAttributes;
import android.media.DeniedByServerException;
import android.media.MediaDrm;
import android.media.MediaDrmException;
import android.media.MediaFormat;
import android.media.MediaTimestamp;
import android.media.PlaybackParams;
import android.media.ResourceBusyException;
import android.media.SyncParams;
import android.media.TimedMetaData;
import android.media.UnsupportedSchemeException;
import android.os.Build;
import android.os.PersistableBundle;
import android.view.Surface;

import androidx.annotation.IntDef;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.List;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.Executor;


/**
 * @hide
 * MediaPlayer2 class can be used to control playback
 * of audio/video files and streams. An example on how to use the methods in
 * this class can be found in {@link android.widget.VideoView}.
 *
 * <p>Topics covered here are:
 * <ol>
 * <li><a href="#StateDiagram">State Diagram</a>
 * <li><a href="#Valid_and_Invalid_States">Valid and Invalid States</a>
 * <li><a href="#Permissions">Permissions</a>
 * <li><a href="#Callbacks">Register informational and error callbacks</a>
 * </ol>
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For more information about how to use MediaPlayer2, read the
 * <a href="{@docRoot}guide/topics/media/mediaplayer.html">Media Playback</a> developer guide.</p>
 * </div>
 *
 * <a name="StateDiagram"></a>
 * <h3>State Diagram</h3>
 *
 * <p>Playback control of audio/video files and streams is managed as a state
 * machine. The following diagram shows the life cycle and the states of a
 * MediaPlayer2 object driven by the supported playback control operations.
 * The ovals represent the states a MediaPlayer2 object may reside
 * in. The arcs represent the playback control operations that drive the object
 * state transition. There are two types of arcs. The arcs with a single arrow
 * head represent synchronous method calls, while those with
 * a double arrow head represent asynchronous method calls.</p>
 *
 * <p><img src="../../../images/mediaplayer_state_diagram.gif"
 *         alt="MediaPlayer State diagram"
 *         border="0" /></p>
 *
 * <p>From this state diagram, one can see that a MediaPlayer2 object has the
 *    following states:</p>
 * <ul>
 *     <li>When a MediaPlayer2 object is just created using <code>create</code> or
 *         after {@link #reset()} is called, it is in the <em>Idle</em> state; and after
 *         {@link #close()} is called, it is in the <em>End</em> state. Between these
 *         two states is the life cycle of the MediaPlayer2 object.
 *         <ul>
 *         <li> It is a programming error to invoke methods such
 *         as {@link #getCurrentPosition()},
 *         {@link #getDuration()}, {@link #getVideoHeight()},
 *         {@link #getVideoWidth()}, {@link #setAudioAttributes(AudioAttributes)},
 *         {@link #setPlayerVolume(float)}, {@link #pause()}, {@link #play()},
 *         {@link #seekTo(long, int)} or
 *         {@link #prepare()} in the <em>Idle</em> state.
 *         <li>It is also recommended that once
 *         a MediaPlayer2 object is no longer being used, call {@link #close()} immediately
 *         so that resources used by the internal player engine associated with the
 *         MediaPlayer2 object can be released immediately. Resource may include
 *         singleton resources such as hardware acceleration components and
 *         failure to call {@link #close()} may cause subsequent instances of
 *         MediaPlayer2 objects to fallback to software implementations or fail
 *         altogether. Once the MediaPlayer2
 *         object is in the <em>End</em> state, it can no longer be used and
 *         there is no way to bring it back to any other state. </li>
 *         <li>Furthermore,
 *         the MediaPlayer2 objects created using <code>new</code> is in the
 *         <em>Idle</em> state.
 *         </li>
 *         </ul>
 *         </li>
 *     <li>In general, some playback control operation may fail due to various
 *         reasons, such as unsupported audio/video format, poorly interleaved
 *         audio/video, resolution too high, streaming timeout, and the like.
 *         Thus, error reporting and recovery is an important concern under
 *         these circumstances. Sometimes, due to programming errors, invoking a playback
 *         control operation in an invalid state may also occur. Under all these
 *         error conditions, the internal player engine invokes a user supplied
 *         MediaPlayer2EventCallback.onError() method if an MediaPlayer2EventCallback has been
 *         registered beforehand via
 *         {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)}.
 *         <ul>
 *         <li>It is important to note that once an error occurs, the
 *         MediaPlayer2 object enters the <em>Error</em> state (except as noted
 *         above), even if an error listener has not been registered by the application.</li>
 *         <li>In order to reuse a MediaPlayer2 object that is in the <em>
 *         Error</em> state and recover from the error,
 *         {@link #reset()} can be called to restore the object to its <em>Idle</em>
 *         state.</li>
 *         <li>It is good programming practice to have your application
 *         register a OnErrorListener to look out for error notifications from
 *         the internal player engine.</li>
 *         <li>IllegalStateException is
 *         thrown to prevent programming errors such as calling
 *         {@link #prepare()}, {@link #setDataSource(DataSourceDesc)}
 *         methods in an invalid state. </li>
 *         </ul>
 *         </li>
 *     <li>Calling
 *         {@link #setDataSource(DataSourceDesc)} transfers a
 *         MediaPlayer2 object in the <em>Idle</em> state to the
 *         <em>Initialized</em> state.
 *         <ul>
 *         <li>An IllegalStateException is thrown if
 *         setDataSource() is called in any other state.</li>
 *         <li>It is good programming
 *         practice to always look out for <code>IllegalArgumentException</code>
 *         and <code>IOException</code> that may be thrown from
 *         <code>setDataSource</code>.</li>
 *         </ul>
 *         </li>
 *     <li>A MediaPlayer2 object must first enter the <em>Prepared</em> state
 *         before playback can be started.
 *         <ul>
 *         <li>There are an asynchronous way that the <em>Prepared</em> state can be reached:
 *         a call to {@link #prepare()} (asynchronous) which
 *         first transfers the object to the <em>Preparing</em> state after the
 *         call returns (which occurs almost right way) while the internal
 *         player engine continues working on the rest of preparation work
 *         until the preparation work completes. When the preparation completes,
 *         the internal player engine then calls a user supplied callback method,
 *         onInfo() of the MediaPlayer2EventCallback interface with {@link #MEDIA_INFO_PREPARED},
 *         if an MediaPlayer2EventCallback is registered beforehand via
 *         {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)}.</li>
 *         <li>It is important to note that
 *         the <em>Preparing</em> state is a transient state, and the behavior
 *         of calling any method with side effect while a MediaPlayer2 object is
 *         in the <em>Preparing</em> state is undefined.</li>
 *         <li>An IllegalStateException is
 *         thrown if {@link #prepare()} is called in
 *         any other state.</li>
 *         <li>While in the <em>Prepared</em> state, properties
 *         such as audio/sound volume, screenOnWhilePlaying, looping can be
 *         adjusted by invoking the corresponding set methods.</li>
 *         </ul>
 *         </li>
 *     <li>To start the playback, {@link #play()} must be called. After
 *         {@link #play()} returns successfully, the MediaPlayer2 object is in the
 *         <em>Started</em> state. {@link #getPlayerState()} can be called to test
 *         whether the MediaPlayer2 object is in the <em>Started</em> state.
 *         <ul>
 *         <li>While in the <em>Started</em> state, the internal player engine calls
 *         a user supplied callback method MediaPlayer2EventCallback.onInfo() with
 *         {@link #MEDIA_INFO_BUFFERING_UPDATE} if an MediaPlayer2EventCallback has been
 *         registered beforehand via
 *         {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)}.
 *         This callback allows applications to keep track of the buffering status
 *         while streaming audio/video.</li>
 *         <li>Calling {@link #play()} has not effect
 *         on a MediaPlayer2 object that is already in the <em>Started</em> state.</li>
 *         </ul>
 *         </li>
 *     <li>Playback can be paused and stopped, and the current playback position
 *         can be adjusted. Playback can be paused via {@link #pause()}. When the call to
 *         {@link #pause()} returns, the MediaPlayer2 object enters the
 *         <em>Paused</em> state. Note that the transition from the <em>Started</em>
 *         state to the <em>Paused</em> state and vice versa happens
 *         asynchronously in the player engine. It may take some time before
 *         the state is updated in calls to {@link #getPlayerState()}, and it can be
 *         a number of seconds in the case of streamed content.
 *         <ul>
 *         <li>Calling {@link #play()} to resume playback for a paused
 *         MediaPlayer2 object, and the resumed playback
 *         position is the same as where it was paused. When the call to
 *         {@link #play()} returns, the paused MediaPlayer2 object goes back to
 *         the <em>Started</em> state.</li>
 *         <li>Calling {@link #pause()} has no effect on
 *         a MediaPlayer2 object that is already in the <em>Paused</em> state.</li>
 *         </ul>
 *         </li>
 *     <li>The playback position can be adjusted with a call to
 *         {@link #seekTo(long, int)}.
 *         <ul>
 *         <li>Although the asynchronuous {@link #seekTo(long, int)}
 *         call returns right away, the actual seek operation may take a while to
 *         finish, especially for audio/video being streamed. When the actual
 *         seek operation completes, the internal player engine calls a user
 *         supplied MediaPlayer2EventCallback.onCallCompleted() with
 *         {@link #CALL_COMPLETED_SEEK_TO}
 *         if an MediaPlayer2EventCallback has been registered beforehand via
 *         {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)}.</li>
 *         <li>Please
 *         note that {@link #seekTo(long, int)} can also be called in the other states,
 *         such as <em>Prepared</em>, <em>Paused</em> and <em>PlaybackCompleted
 *         </em> state. When {@link #seekTo(long, int)} is called in those states,
 *         one video frame will be displayed if the stream has video and the requested
 *         position is valid.
 *         </li>
 *         <li>Furthermore, the actual current playback position
 *         can be retrieved with a call to {@link #getCurrentPosition()}, which
 *         is helpful for applications such as a Music player that need to keep
 *         track of the playback progress.</li>
 *         </ul>
 *         </li>
 *     <li>When the playback reaches the end of stream, the playback completes.
 *         <ul>
 *         <li>If current source is set to loop by {@link #loopCurrent(boolean)},
 *         the MediaPlayer2 object shall remain in the <em>Started</em> state.</li>
 *         <li>If the looping mode was set to <var>false
 *         </var>, the player engine calls a user supplied callback method,
 *         MediaPlayer2EventCallback.onCompletion(), if an MediaPlayer2EventCallback is
 *         registered beforehand via
 *         {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)}.
 *         The invoke of the callback signals that the object is now in the <em>
 *         PlaybackCompleted</em> state.</li>
 *         <li>While in the <em>PlaybackCompleted</em>
 *         state, calling {@link #play()} can restart the playback from the
 *         beginning of the audio/video source.</li>
 * </ul>
 *
 *
 * <a name="Valid_and_Invalid_States"></a>
 * <h3>Valid and invalid states</h3>
 *
 * <table border="0" cellspacing="0" cellpadding="0">
 * <tr><td>Method Name </p></td>
 *     <td>Valid Sates </p></td>
 *     <td>Invalid States </p></td>
 *     <td>Comments </p></td></tr>
 * <tr><td>attachAuxEffect </p></td>
 *     <td>{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} </p></td>
 *     <td>{Idle, Error} </p></td>
 *     <td>This method must be called after setDataSource.
 *     Calling it does not change the object state. </p></td></tr>
 * <tr><td>getAudioSessionId </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>getCurrentPosition </p></td>
 *     <td>{Idle, Initialized, Prepared, Started, Paused, Stopped,
 *         PlaybackCompleted} </p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change the
 *         state. Calling this method in an invalid state transfers the object
 *         to the <em>Error</em> state. </p></td></tr>
 * <tr><td>getDuration </p></td>
 *     <td>{Prepared, Started, Paused, Stopped, PlaybackCompleted} </p></td>
 *     <td>{Idle, Initialized, Error} </p></td>
 *     <td>Successful invoke of this method in a valid state does not change the
 *         state. Calling this method in an invalid state transfers the object
 *         to the <em>Error</em> state. </p></td></tr>
 * <tr><td>getVideoHeight </p></td>
 *     <td>{Idle, Initialized, Prepared, Started, Paused, Stopped,
 *         PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change the
 *         state. Calling this method in an invalid state transfers the object
 *         to the <em>Error</em> state.  </p></td></tr>
 * <tr><td>getVideoWidth </p></td>
 *     <td>{Idle, Initialized, Prepared, Started, Paused, Stopped,
 *         PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change
 *         the state. Calling this method in an invalid state transfers the
 *         object to the <em>Error</em> state. </p></td></tr>
 * <tr><td>getPlayerState </p></td>
 *     <td>{Idle, Initialized, Prepared, Started, Paused, Stopped,
 *          PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change
 *         the state. Calling this method in an invalid state transfers the
 *         object to the <em>Error</em> state. </p></td></tr>
 * <tr><td>pause </p></td>
 *     <td>{Started, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Prepared, Stopped, Error}</p></td>
 *     <td>Successful invoke of this method in a valid state transfers the
 *         object to the <em>Paused</em> state. Calling this method in an
 *         invalid state transfers the object to the <em>Error</em> state.</p></td></tr>
 * <tr><td>prepare </p></td>
 *     <td>{Initialized, Stopped} </p></td>
 *     <td>{Idle, Prepared, Started, Paused, PlaybackCompleted, Error} </p></td>
 *     <td>Successful invoke of this method in a valid state transfers the
 *         object to the <em>Preparing</em> state. Calling this method in an
 *         invalid state throws an IllegalStateException.</p></td></tr>
 * <tr><td>release </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>After {@link #close()}, the object is no longer available. </p></td></tr>
 * <tr><td>reset </p></td>
 *     <td>{Idle, Initialized, Prepared, Started, Paused, Stopped,
 *         PlaybackCompleted, Error}</p></td>
 *     <td>{}</p></td>
 *     <td>After {@link #reset()}, the object is like being just created.</p></td></tr>
 * <tr><td>seekTo </p></td>
 *     <td>{Prepared, Started, Paused, PlaybackCompleted} </p></td>
 *     <td>{Idle, Initialized, Stopped, Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change
 *         the state. Calling this method in an invalid state transfers the
 *         object to the <em>Error</em> state. </p></td></tr>
 * <tr><td>setAudioAttributes </p></td>
 *     <td>{Idle, Initialized, Stopped, Prepared, Started, Paused,
 *          PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method does not change the state. In order for the
 *         target audio attributes type to become effective, this method must be called before
 *         prepare().</p></td></tr>
 * <tr><td>setAudioSessionId </p></td>
 *     <td>{Idle} </p></td>
 *     <td>{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted,
 *          Error} </p></td>
 *     <td>This method must be called in idle state as the audio session ID must be known before
 *         calling setDataSource. Calling it does not change the object
 *         state. </p></td></tr>
 * <tr><td>setAudioStreamType (deprecated)</p></td>
 *     <td>{Idle, Initialized, Stopped, Prepared, Started, Paused,
 *          PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method does not change the state. In order for the
 *         target audio stream type to become effective, this method must be called before
 *         prepare().</p></td></tr>
 * <tr><td>setAuxEffectSendLevel </p></td>
 *     <td>any</p></td>
 *     <td>{} </p></td>
 *     <td>Calling this method does not change the object state. </p></td></tr>
 * <tr><td>setDataSource </p></td>
 *     <td>{Idle} </p></td>
 *     <td>{Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted,
 *          Error} </p></td>
 *     <td>Successful invoke of this method in a valid state transfers the
 *         object to the <em>Initialized</em> state. Calling this method in an
 *         invalid state throws an IllegalStateException.</p></td></tr>
 * <tr><td>setDisplay </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>setSurface </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>loopCurrent </p></td>
 *     <td>{Idle, Initialized, Stopped, Prepared, Started, Paused,
 *         PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method in a valid state does not change
 *         the state. Calling this method in an
 *         invalid state transfers the object to the <em>Error</em> state.</p></td></tr>
 * <tr><td>isLooping </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>setDrmEventCallback </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>setMediaPlayer2EventCallback </p></td>
 *     <td>any </p></td>
 *     <td>{} </p></td>
 *     <td>This method can be called in any state and calling it does not change
 *         the object state. </p></td></tr>
 * <tr><td>setPlaybackParams</p></td>
 *     <td>{Initialized, Prepared, Started, Paused, PlaybackCompleted, Error}</p></td>
 *     <td>{Idle, Stopped} </p></td>
 *     <td>This method will change state in some cases, depending on when it's called.
 *         </p></td></tr>
 * <tr><td>setPlayerVolume </p></td>
 *     <td>{Idle, Initialized, Stopped, Prepared, Started, Paused,
 *          PlaybackCompleted}</p></td>
 *     <td>{Error}</p></td>
 *     <td>Successful invoke of this method does not change the state.
 * <tr><td>play </p></td>
 *     <td>{Prepared, Started, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Stopped, Error}</p></td>
 *     <td>Successful invoke of this method in a valid state transfers the
 *         object to the <em>Started</em> state. Calling this method in an
 *         invalid state transfers the object to the <em>Error</em> state.</p></td></tr>
 * <tr><td>stop </p></td>
 *     <td>{Prepared, Started, Stopped, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Error}</p></td>
 *     <td>Successful invoke of this method in a valid state transfers the
 *         object to the <em>Stopped</em> state. Calling this method in an
 *         invalid state transfers the object to the <em>Error</em> state.</p></td></tr>
 * <tr><td>getTrackInfo </p></td>
 *     <td>{Prepared, Started, Stopped, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Error}</p></td>
 *     <td>Successful invoke of this method does not change the state.</p></td></tr>
 * <tr><td>selectTrack </p></td>
 *     <td>{Prepared, Started, Stopped, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Error}</p></td>
 *     <td>Successful invoke of this method does not change the state.</p></td></tr>
 * <tr><td>deselectTrack </p></td>
 *     <td>{Prepared, Started, Stopped, Paused, PlaybackCompleted}</p></td>
 *     <td>{Idle, Initialized, Error}</p></td>
 *     <td>Successful invoke of this method does not change the state.</p></td></tr>
 *
 * </table>
 *
 * <a name="Permissions"></a>
 * <h3>Permissions</h3>
 * <p>One may need to declare a corresponding WAKE_LOCK permission {@link
 * android.R.styleable#AndroidManifestUsesPermission &lt;uses-permission&gt;}
 * element.
 *
 * <p>This class requires the {@link android.Manifest.permission#INTERNET} permission
 * when used with network-based content.
 *
 * <a name="Callbacks"></a>
 * <h3>Callbacks</h3>
 * <p>Applications may want to register for informational and error
 * events in order to be informed of some internal state update and
 * possible runtime errors during playback or streaming. Registration for
 * these events is done by properly setting the appropriate listeners (via calls
 * to
 * {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)},
 * {@link #setDrmEventCallback(Executor, DrmEventCallback)}).
 * In order to receive the respective callback
 * associated with these listeners, applications are required to create
 * MediaPlayer2 objects on a thread with its own Looper running (main UI
 * thread by default has a Looper running).
 *
 */
@TargetApi(Build.VERSION_CODES.P)
@RestrictTo(LIBRARY_GROUP)
public abstract class MediaPlayer2 extends MediaPlayerBase {
    /**
     * Create a MediaPlayer2 object.
     *
     * @return A MediaPlayer2 object created
     */
    public static final MediaPlayer2 create() {
        return new MediaPlayer2Impl();
    }

    /**
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    public MediaPlayer2() { }

    /**
     * Releases the resources held by this {@code MediaPlayer2} object.
     *
     * It is considered good practice to call this method when you're
     * done using the MediaPlayer2. In particular, whenever an Activity
     * of an application is paused (its onPause() method is called),
     * or stopped (its onStop() method is called), this method should be
     * invoked to release the MediaPlayer2 object, unless the application
     * has a special need to keep the object around. In addition to
     * unnecessary resources (such as memory and instances of codecs)
     * being held, failure to call this method immediately if a
     * MediaPlayer2 object is no longer needed may also lead to
     * continuous battery consumption for mobile devices, and playback
     * failure for other applications if no multiple instances of the
     * same codec are supported on a device. Even if multiple instances
     * of the same codec are supported, some performance degradation
     * may be expected when unnecessary multiple instances are used
     * at the same time.
     *
     * {@code close()} may be safely called after a prior {@code close()}.
     * This class implements the Java {@code AutoCloseable} interface and
     * may be used with try-with-resources.
     */
    // This is a synchronous call.
    @Override
    public abstract void close();

    /**
     * Starts or resumes playback. If playback had previously been paused,
     * playback will continue from where it was paused. If playback had
     * reached end of stream and been paused, or never started before,
     * playback will start at the beginning. If the source had not been
     * prepared, the player will prepare the source and play.
     *
     */
    // This is an asynchronous call.
    @Override
    public abstract void play();

    /**
     * Prepares the player for playback, asynchronously.
     *
     * After setting the datasource and the display surface, you need to
     * call prepare().
     *
     */
    // This is an asynchronous call.
    @Override
    public abstract void prepare();

    /**
     * Pauses playback. Call play() to resume.
     */
    // This is an asynchronous call.
    @Override
    public abstract void pause();

    /**
     * Tries to play next data source if applicable.
     */
    // This is an asynchronous call.
    @Override
    public abstract void skipToNext();

    /**
     * Moves the media to specified time position.
     * Same as {@link #seekTo(long, int)} with {@code mode = SEEK_PREVIOUS_SYNC}.
     *
     * @param msec the offset in milliseconds from the start to seek to
     */
    // This is an asynchronous call.
    @Override
    public void seekTo(long msec) {
        seekTo(msec, SEEK_PREVIOUS_SYNC /* mode */);
    }

    /**
     * Gets the current playback position.
     *
     * @return the current position in milliseconds
     */
    @Override
    public abstract long getCurrentPosition();

    /**
     * Gets the duration of the file.
     *
     * @return the duration in milliseconds, if no duration is available
     *         (for example, if streaming live content), -1 is returned.
     */
    @Override
    public abstract long getDuration();

    /**
     * Gets the current buffered media source position received through progressive downloading.
     * The received buffering percentage indicates how much of the content has been buffered
     * or played. For example a buffering update of 80 percent when half the content
     * has already been played indicates that the next 30 percent of the
     * content to play has been buffered.
     *
     * @return the current buffered media source position in milliseconds
     */
    @Override
    public abstract long getBufferedPosition();

    /**
     * Gets the current player state.
     *
     * @return the current player state.
     */
    @Override
    public abstract @PlayerState int getPlayerState();

    /**
     * Gets the current buffering state of the player.
     * During buffering, see {@link #getBufferedPosition()} for the quantifying the amount already
     * buffered.
     * @return the buffering state, one of the following:
     */
    @Override
    public abstract @BuffState int getBufferingState();

    /**
     * Sets the audio attributes for this MediaPlayer2.
     * See {@link AudioAttributes} for how to build and configure an instance of this class.
     * You must call this method before {@link #prepare()} in order
     * for the audio attributes to become effective thereafter.
     * @param attributes a non-null set of audio attributes
     */
    // This is an asynchronous call.
    @Override
    public abstract void setAudioAttributes(@NonNull AudioAttributesCompat attributes);

    /**
     * Gets the audio attributes for this MediaPlayer2.
     * @return attributes a set of audio attributes
     */
    @Override
    public abstract @Nullable AudioAttributesCompat getAudioAttributes();

    /**
     * Sets the data source as described by a DataSourceDesc.
     *
     * @param dsd the descriptor of data source you want to play
     */
    // This is an asynchronous call.
    @Override
    public abstract void setDataSource(@NonNull DataSourceDesc dsd);

    /**
     * Sets a single data source as described by a DataSourceDesc which will be played
     * after current data source is finished.
     *
     * @param dsd the descriptor of data source you want to play after current one
     */
    // This is an asynchronous call.
    @Override
    public abstract void setNextDataSource(@NonNull DataSourceDesc dsd);

    /**
     * Sets a list of data sources to be played sequentially after current data source is done.
     *
     * @param dsds the list of data sources you want to play after current one
     */
    // This is an asynchronous call.
    @Override
    public abstract void setNextDataSources(@NonNull List<DataSourceDesc> dsds);

    /**
     * Gets the current data source as described by a DataSourceDesc.
     *
     * @return the current DataSourceDesc
     */
    @Override
    public abstract @NonNull DataSourceDesc getCurrentDataSource();

    /**
     * Configures the player to loop on the current data source.
     * @param loop true if the current data source is meant to loop.
     */
    // This is an asynchronous call.
    @Override
    public abstract void loopCurrent(boolean loop);

    /**
     * Sets the playback speed.
     * A value of 1.0f is the default playback value.
     * A negative value indicates reverse playback, check {@link #isReversePlaybackSupported()}
     * before using negative values.<br>
     * After changing the playback speed, it is recommended to query the actual speed supported
     * by the player, see {@link #getPlaybackSpeed()}.
     * @param speed the desired playback speed
     */
    // This is an asynchronous call.
    @Override
    public abstract void setPlaybackSpeed(float speed);

    /**
     * Returns the actual playback speed to be used by the player when playing.
     * Note that it may differ from the speed set in {@link #setPlaybackSpeed(float)}.
     * @return the actual playback speed
     */
    @Override
    public float getPlaybackSpeed() {
        return 1.0f;
    }

    /**
     * Indicates whether reverse playback is supported.
     * Reverse playback is indicated by negative playback speeds, see
     * {@link #setPlaybackSpeed(float)}.
     * @return true if reverse playback is supported.
     */
    @Override
    public boolean isReversePlaybackSupported() {
        return false;
    }

    /**
     * Sets the volume of the audio of the media to play, expressed as a linear multiplier
     * on the audio samples.
     * Note that this volume is specific to the player, and is separate from stream volume
     * used across the platform.<br>
     * A value of 0.0f indicates muting, a value of 1.0f is the nominal unattenuated and unamplified
     * gain. See {@link #getMaxPlayerVolume()} for the volume range supported by this player.
     * @param volume a value between 0.0f and {@link #getMaxPlayerVolume()}.
     */
    // This is an asynchronous call.
    @Override
    public abstract void setPlayerVolume(float volume);

    /**
     * Returns the current volume of this player to this player.
     * Note that it does not take into account the associated stream volume.
     * @return the player volume.
     */
    @Override
    public abstract float getPlayerVolume();

    /**
     * @return the maximum volume that can be used in {@link #setPlayerVolume(float)}.
     */
    @Override
    public float getMaxPlayerVolume() {
        return 1.0f;
    }

    /**
     * Adds a callback to be notified of events for this player.
     * @param e the {@link Executor} to be used for the events.
     * @param cb the callback to receive the events.
     */
    // This is a synchronous call.
    @Override
    public abstract void registerPlayerEventCallback(@NonNull Executor e,
                                                     @NonNull PlayerEventCallback cb);

    /**
     * Removes a previously registered callback for player events
     * @param cb the callback to remove
     */
    // This is a synchronous call.
    @Override
    public abstract void unregisterPlayerEventCallback(@NonNull PlayerEventCallback cb);

    /**
     * Insert a task in the command queue to help the client to identify whether a batch
     * of commands has been finished. When this command is processed, a notification
     * {@code MediaPlayer2EventCallback.onCommandLabelReached} will be fired with the
     * given {@code label}.
     *
     * @see MediaPlayer2EventCallback#onCommandLabelReached
     *
     * @param label An application specific Object used to help to identify the completeness
     * of a batch of commands.
     */
    // This is an asynchronous call.
    public void notifyWhenCommandLabelReached(@NonNull Object label) { }

    /**
     * Sets the {@link Surface} to be used as the sink for the video portion of
     * the media.  Setting a
     * Surface will un-set any Surface or SurfaceHolder that was previously set.
     * A null surface will result in only the audio track being played.
     *
     * If the Surface sends frames to a {@link SurfaceTexture}, the timestamps
     * returned from {@link SurfaceTexture#getTimestamp()} will have an
     * unspecified zero point.  These timestamps cannot be directly compared
     * between different media sources, different instances of the same media
     * source, or multiple runs of the same program.  The timestamp is normally
     * monotonically increasing and is unaffected by time-of-day adjustments,
     * but it is reset when the position is set.
     *
     * @param surface The {@link Surface} to be used for the video portion of
     * the media.
     * @throws IllegalStateException if the internal player engine has not been
     * initialized or has been released.
     */
    // This is an asynchronous call.
    public abstract void setSurface(Surface surface);

    /* Do not change these video scaling mode values below without updating
     * their counterparts in system/window.h! Please do not forget to update
     * {@link #isVideoScalingModeSupported} when new video scaling modes
     * are added.
     */
    /**
     * Specifies a video scaling mode. The content is stretched to the
     * surface rendering area. When the surface has the same aspect ratio
     * as the content, the aspect ratio of the content is maintained;
     * otherwise, the aspect ratio of the content is not maintained when video
     * is being rendered.
     * There is no content cropping with this video scaling mode.
     */
    public static final int VIDEO_SCALING_MODE_SCALE_TO_FIT = 1;

    /**
     * Discards all pending commands.
     */
    // This is a synchronous call.
    public abstract void clearPendingCommands();

    /**
     * Returns the width of the video.
     *
     * @return the width of the video, or 0 if there is no video,
     * no display surface was set, or the width has not been determined
     * yet. The {@code MediaPlayer2EventCallback} can be registered via
     * {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)} to provide a
     * notification {@code MediaPlayer2EventCallback.onVideoSizeChanged} when the width
     * is available.
     */
    public abstract int getVideoWidth();

    /**
     * Returns the height of the video.
     *
     * @return the height of the video, or 0 if there is no video,
     * no display surface was set, or the height has not been determined
     * yet. The {@code MediaPlayer2EventCallback} can be registered via
     * {@link #setMediaPlayer2EventCallback(Executor, MediaPlayer2EventCallback)} to provide a
     * notification {@code MediaPlayer2EventCallback.onVideoSizeChanged} when the height is
     * available.
     */
    public abstract int getVideoHeight();

    /**
     * Return Metrics data about the current player.
     *
     * @return a {@link PersistableBundle} containing the set of attributes and values
     * available for the media being handled by this instance of MediaPlayer2
     * The attributes are descibed in {@link MetricsConstants}.
     *
     *  Additional vendor-specific fields may also be present in
     *  the return value.
     *  @hide
     *  TODO: This method is not ready for public. Currently returns metrics data in MediaPlayer1.
     */
    @RestrictTo(LIBRARY_GROUP)
    public abstract PersistableBundle getMetrics();

    /**
     * Sets playback rate using {@link PlaybackParams}. The object sets its internal
     * PlaybackParams to the input, except that the object remembers previous speed
     * when input speed is zero. This allows the object to resume at previous speed
     * when play() is called. Calling it before the object is prepared does not change
     * the object state. After the object is prepared, calling it with zero speed is
     * equivalent to calling pause(). After the object is prepared, calling it with
     * non-zero speed is equivalent to calling play().
     *
     * @param params the playback params.
     */
    // This is an asynchronous call.
    public abstract void setPlaybackParams(@NonNull PlaybackParams params);

    /**
     * Gets the playback params, containing the current playback rate.
     *
     * @return the playback params.
     */
    @NonNull
    public abstract PlaybackParams getPlaybackParams();

    /**
     * Sets A/V sync mode.
     *
     * @param params the A/V sync params to apply
     */
    // This is an asynchronous call.
    public abstract void setSyncParams(@NonNull SyncParams params);

    /**
     * Gets the A/V sync mode.
     *
     * @return the A/V sync params
     */
    @NonNull
    public abstract SyncParams getSyncParams();

    /**
     * Seek modes used in method seekTo(long, int) to move media position
     * to a specified location.
     *
     * Do not change these mode values without updating their counterparts
     * in include/media/IMediaSource.h!
     */
    /**
     * This mode is used with {@link #seekTo(long, int)} to move media position to
     * a sync (or key) frame associated with a data source that is located
     * right before or at the given time.
     *
     * @see #seekTo(long, int)
     */
    public static final int SEEK_PREVIOUS_SYNC    = 0x00;
    /**
     * This mode is used with {@link #seekTo(long, int)} to move media position to
     * a sync (or key) frame associated with a data source that is located
     * right after or at the given time.
     *
     * @see #seekTo(long, int)
     */
    public static final int SEEK_NEXT_SYNC        = 0x01;
    /**
     * This mode is used with {@link #seekTo(long, int)} to move media position to
     * a sync (or key) frame associated with a data source that is located
     * closest to (in time) or at the given time.
     *
     * @see #seekTo(long, int)
     */
    public static final int SEEK_CLOSEST_SYNC     = 0x02;
    /**
     * This mode is used with {@link #seekTo(long, int)} to move media position to
     * a frame (not necessarily a key frame) associated with a data source that
     * is located closest to or at the given time.
     *
     * @see #seekTo(long, int)
     */
    public static final int SEEK_CLOSEST          = 0x03;

    /** @hide */
    @IntDef(flag = false, /*prefix = "SEEK",*/ value = {
            SEEK_PREVIOUS_SYNC,
            SEEK_NEXT_SYNC,
            SEEK_CLOSEST_SYNC,
            SEEK_CLOSEST,
    })
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface SeekMode {}

    /**
     * Moves the media to specified time position by considering the given mode.
     * <p>
     * When seekTo is finished, the user will be notified via OnSeekComplete supplied by the user.
     * There is at most one active seekTo processed at any time. If there is a to-be-completed
     * seekTo, new seekTo requests will be queued in such a way that only the last request
     * is kept. When current seekTo is completed, the queued request will be processed if
     * that request is different from just-finished seekTo operation, i.e., the requested
     * position or mode is different.
     *
     * @param msec the offset in milliseconds from the start to seek to.
     * When seeking to the given time position, there is no guarantee that the data source
     * has a frame located at the position. When this happens, a frame nearby will be rendered.
     * If msec is negative, time position zero will be used.
     * If msec is larger than duration, duration will be used.
     * @param mode the mode indicating where exactly to seek to.
     */
    // This is an asynchronous call.
    public abstract void seekTo(long msec, @SeekMode int mode);

    /**
     * Get current playback position as a {@link MediaTimestamp}.
     * <p>
     * The MediaTimestamp represents how the media time correlates to the system time in
     * a linear fashion using an anchor and a clock rate. During regular playback, the media
     * time moves fairly constantly (though the anchor frame may be rebased to a current
     * system time, the linear correlation stays steady). Therefore, this method does not
     * need to be called often.
     * <p>
     * To help users get current playback position, this method always anchors the timestamp
     * to the current {@link System#nanoTime system time}, so
     * {@link MediaTimestamp#getAnchorMediaTimeUs} can be used as current playback position.
     *
     * @return a MediaTimestamp object if a timestamp is available, or {@code null} if no timestamp
     *         is available, e.g. because the media player has not been initialized.
     *
     * @see MediaTimestamp
     */
    @Nullable
    public abstract MediaTimestamp getTimestamp();

    /**
     * Resets the MediaPlayer2 to its uninitialized state. After calling
     * this method, you will have to initialize it again by setting the
     * data source and calling prepare().
     */
    // This is a synchronous call.
    @Override
    public abstract void reset();

    /**
     * Sets the audio session ID.
     *
     * @param sessionId the audio session ID.
     * The audio session ID is a system wide unique identifier for the audio stream played by
     * this MediaPlayer2 instance.
     * The primary use of the audio session ID  is to associate audio effects to a particular
     * instance of MediaPlayer2: if an audio session ID is provided when creating an audio effect,
     * this effect will be applied only to the audio content of media players within the same
     * audio session and not to the output mix.
     * When created, a MediaPlayer2 instance automatically generates its own audio session ID.
     * However, it is possible to force this player to be part of an already existing audio session
     * by calling this method.
     * This method must be called before one of the overloaded <code> setDataSource </code> methods.
     */
    // This is an asynchronous call.
    public abstract void setAudioSessionId(int sessionId);

    /**
     * Returns the audio session ID.
     *
     * @return the audio session ID. {@see #setAudioSessionId(int)}
     * Note that the audio session ID is 0 only if a problem occured when the MediaPlayer2 was
     * contructed.
     */
    public abstract int getAudioSessionId();

    /**
     * Attaches an auxiliary effect to the player. A typical auxiliary effect is a reverberation
     * effect which can be applied on any sound source that directs a certain amount of its
     * energy to this effect. This amount is defined by setAuxEffectSendLevel().
     * See {@link #setAuxEffectSendLevel(float)}.
     * <p>After creating an auxiliary effect (e.g.
     * {@link android.media.audiofx.EnvironmentalReverb}), retrieve its ID with
     * {@link android.media.audiofx.AudioEffect#getId()} and use it when calling this method
     * to attach the player to the effect.
     * <p>To detach the effect from the player, call this method with a null effect id.
     * <p>This method must be called after one of the overloaded <code> setDataSource </code>
     * methods.
     * @param effectId system wide unique id of the effect to attach
     */
    // This is an asynchronous call.
    public abstract void attachAuxEffect(int effectId);


    /**
     * Sets the send level of the player to the attached auxiliary effect.
     * See {@link #attachAuxEffect(int)}. The level value range is 0 to 1.0.
     * <p>By default the send level is 0, so even if an effect is attached to the player
     * this method must be called for the effect to be applied.
     * <p>Note that the passed level value is a raw scalar. UI controls should be scaled
     * logarithmically: the gain applied by audio framework ranges from -72dB to 0dB,
     * so an appropriate conversion from linear UI input x to level is:
     * x == 0 -> level = 0
     * 0 < x <= R -> level = 10^(72*(x-R)/20/R)
     * @param level send level scalar
     */
    // This is an asynchronous call.
    public abstract void setAuxEffectSendLevel(float level);

    /**
     * Class for MediaPlayer2 to return each audio/video/subtitle track's metadata.
     *
     * @see MediaPlayer2#getTrackInfo
     */
    public abstract static class TrackInfo {
        /**
         * Gets the track type.
         * @return TrackType which indicates if the track is video, audio, timed text.
         */
        public abstract int getTrackType();

        /**
         * Gets the language code of the track.
         * @return a language code in either way of ISO-639-1 or ISO-639-2.
         * When the language is unknown or could not be determined,
         * ISO-639-2 language code, "und", is returned.
         */
        public abstract String getLanguage();

        /**
         * Gets the {@link MediaFormat} of the track.  If the format is
         * unknown or could not be determined, null is returned.
         */
        public abstract MediaFormat getFormat();

        public static final int MEDIA_TRACK_TYPE_UNKNOWN = 0;
        public static final int MEDIA_TRACK_TYPE_VIDEO = 1;
        public static final int MEDIA_TRACK_TYPE_AUDIO = 2;

        /** @hide */
        @RestrictTo(LIBRARY_GROUP)
        public static final int MEDIA_TRACK_TYPE_TIMEDTEXT = 3;

        public static final int MEDIA_TRACK_TYPE_SUBTITLE = 4;
        public static final int MEDIA_TRACK_TYPE_METADATA = 5;

        @Override
        public abstract String toString();
    };

    /**
     * Returns a List of track information.
     *
     * @return List of track info. The total number of tracks is the array length.
     * Must be called again if an external timed text source has been added after
     * addTimedTextSource method is called.
     */
    public abstract List<TrackInfo> getTrackInfo();

    /**
     * Returns the index of the audio, video, or subtitle track currently selected for playback,
     * The return value is an index into the array returned by {@link #getTrackInfo()}, and can
     * be used in calls to {@link #selectTrack(int)} or {@link #deselectTrack(int)}.
     *
     * @param trackType should be one of {@link TrackInfo#MEDIA_TRACK_TYPE_VIDEO},
     * {@link TrackInfo#MEDIA_TRACK_TYPE_AUDIO}, or
     * {@link TrackInfo#MEDIA_TRACK_TYPE_SUBTITLE}
     * @return index of the audio, video, or subtitle track currently selected for playback;
     * a negative integer is returned when there is no selected track for {@code trackType} or
     * when {@code trackType} is not one of audio, video, or subtitle.
     * @throws IllegalStateException if called after {@link #close()}
     *
     * @see #getTrackInfo()
     * @see #selectTrack(int)
     * @see #deselectTrack(int)
     */
    public abstract int getSelectedTrack(int trackType);

    /**
     * Selects a track.
     * <p>
     * If a MediaPlayer2 is in invalid state, it throws an IllegalStateException exception.
     * If a MediaPlayer2 is in <em>Started</em> state, the selected track is presented immediately.
     * If a MediaPlayer2 is not in Started state, it just marks the track to be played.
     * </p>
     * <p>
     * In any valid state, if it is called multiple times on the same type of track (ie. Video,
     * Audio, Timed Text), the most recent one will be chosen.
     * </p>
     * <p>
     * The first audio and video tracks are selected by default if available, even though
     * this method is not called. However, no timed text track will be selected until
     * this function is called.
     * </p>
     * <p>
     * Currently, only timed text tracks or audio tracks can be selected via this method.
     * In addition, the support for selecting an audio track at runtime is pretty limited
     * in that an audio track can only be selected in the <em>Prepared</em> state.
     * </p>
     * @param index the index of the track to be selected. The valid range of the index
     * is 0..total number of track - 1. The total number of tracks as well as the type of
     * each individual track can be found by calling {@link #getTrackInfo()} method.
     * @throws IllegalStateException if called in an invalid state.
     *
     * @see MediaPlayer2#getTrackInfo
     */
    // This is an asynchronous call.
    public abstract void selectTrack(int index);

    /**
     * Deselect a track.
     * <p>
     * Currently, the track must be a timed text track and no audio or video tracks can be
     * deselected. If the timed text track identified by index has not been
     * selected before, it throws an exception.
     * </p>
     * @param index the index of the track to be deselected. The valid range of the index
     * is 0..total number of tracks - 1. The total number of tracks as well as the type of
     * each individual track can be found by calling {@link #getTrackInfo()} method.
     * @throws IllegalStateException if called in an invalid state.
     *
     * @see MediaPlayer2#getTrackInfo
     */
    // This is an asynchronous call.
    public abstract void deselectTrack(int index);

    /**
     * Interface definition for callbacks to be invoked when the player has the corresponding
     * events.
     */
    public abstract static class MediaPlayer2EventCallback {
        /**
         * Called to indicate the video size
         *
         * The video size (width and height) could be 0 if there was no video,
         * no display surface was set, or the value was not determined yet.
         *
         * @param mp the MediaPlayer2 associated with this callback
         * @param dsd the DataSourceDesc of this data source
         * @param width the width of the video
         * @param height the height of the video
         */
        public void onVideoSizeChanged(
                MediaPlayer2 mp, DataSourceDesc dsd, int width, int height) { }

        /**
         * Called to indicate available timed metadata
         * <p>
         * This method will be called as timed metadata is extracted from the media,
         * in the same order as it occurs in the media. The timing of this event is
         * not controlled by the associated timestamp.
         * <p>
         * Currently only HTTP live streaming data URI's embedded with timed ID3 tags generates
         * {@link TimedMetaData}.
         *
         * @see MediaPlayer2#selectTrack(int)
         * @see TimedMetaData
         *
         * @param mp the MediaPlayer2 associated with this callback
         * @param dsd the DataSourceDesc of this data source
         * @param data the timed metadata sample associated with this event
         */
        public void onTimedMetaDataAvailable(
                MediaPlayer2 mp, DataSourceDesc dsd, TimedMetaData data) { }

        /**
         * Called to indicate an error.
         *
         * @param mp the MediaPlayer2 the error pertains to
         * @param dsd the DataSourceDesc of this data source
         * @param what the type of error that has occurred.
         * @param extra an extra code, specific to the error. Typically
         * implementation dependent.
         */
        public void onError(
                MediaPlayer2 mp, DataSourceDesc dsd, @MediaError int what, int extra) { }

        /**
         * Called to indicate an info or a warning.
         *
         * @param mp the MediaPlayer2 the info pertains to.
         * @param dsd the DataSourceDesc of this data source
         * @param what the type of info or warning.
         * @param extra an extra code, specific to the info. Typically
         * implementation dependent.
         */
        public void onInfo(MediaPlayer2 mp, DataSourceDesc dsd, @MediaInfo int what, int extra) { }

        /**
         * Called to acknowledge an API call.
         *
         * @param mp the MediaPlayer2 the call was made on.
         * @param dsd the DataSourceDesc of this data source
         * @param what the enum for the API call.
         * @param status the returned status code for the call.
         */
        public void onCallCompleted(
                MediaPlayer2 mp, DataSourceDesc dsd, @CallCompleted int what,
                @CallStatus int status) { }

        /**
         * Called to indicate media clock has changed.
         *
         * @param mp the MediaPlayer2 the media time pertains to.
         * @param dsd the DataSourceDesc of this data source
         * @param timestamp the new media clock.
         */
        public void onMediaTimeChanged(
                MediaPlayer2 mp, DataSourceDesc dsd, MediaTimestamp timestamp) { }

        /**
         * Called to indicate {@link #notifyWhenCommandLabelReached(Object)} has been processed.
         *
         * @param mp the MediaPlayer2 {@link #notifyWhenCommandLabelReached(Object)} was called on.
         * @param label the application specific Object given by
         *        {@link #notifyWhenCommandLabelReached(Object)}.
         */
        public void onCommandLabelReached(MediaPlayer2 mp, @NonNull Object label) { }

        /* TODO : uncomment below once API is available in supportlib.
         * Called when when a player subtitle track has new subtitle data available.
         * @param mp the player that reports the new subtitle data
         * @param data the subtitle data
         */
        // public void onSubtitleData(MediaPlayer2 mp, @NonNull SubtitleData data) { }
    }

    /**
     * Sets the callback to be invoked when the media source is ready for playback.
     *
     * @param eventCallback the callback that will be run
     * @param executor the executor through which the callback should be invoked
     */
    // This is a synchronous call.
    public abstract void setMediaPlayer2EventCallback(
            @NonNull Executor executor, @NonNull MediaPlayer2EventCallback eventCallback);

    /**
     * Clears the {@link MediaPlayer2EventCallback}.
     */
    // This is a synchronous call.
    public abstract void clearMediaPlayer2EventCallback();

    /* Do not change these values without updating their counterparts
     * in include/media/mediaplayer2.h!
     */
    /** Unspecified media player error.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onError
     */
    public static final int MEDIA_ERROR_UNKNOWN = 1;

    /** The video is streamed and its container is not valid for progressive
     * playback i.e the video's index (e.g moov atom) is not at the start of the
     * file.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onError
     */
    public static final int MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK = 200;

    /** File or network related operation errors. */
    public static final int MEDIA_ERROR_IO = -1004;
    /** Bitstream is not conforming to the related coding standard or file spec. */
    public static final int MEDIA_ERROR_MALFORMED = -1007;
    /** Bitstream is conforming to the related coding standard or file spec, but
     * the media framework does not support the feature. */
    public static final int MEDIA_ERROR_UNSUPPORTED = -1010;
    /** Some operation takes too long to complete, usually more than 3-5 seconds. */
    public static final int MEDIA_ERROR_TIMED_OUT = -110;

    /** Unspecified low-level system error. This value originated from UNKNOWN_ERROR in
     * system/core/include/utils/Errors.h
     * @see MediaPlayer2.MediaPlayer2EventCallback#onError
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final int MEDIA_ERROR_SYSTEM = -2147483648;

    /**
     * @hide
     */
    @IntDef(flag = false, /*prefix = "MEDIA_ERROR",*/ value = {
            MEDIA_ERROR_UNKNOWN,
            MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK,
            MEDIA_ERROR_IO,
            MEDIA_ERROR_MALFORMED,
            MEDIA_ERROR_UNSUPPORTED,
            MEDIA_ERROR_TIMED_OUT,
            MEDIA_ERROR_SYSTEM
    })
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface MediaError {}

    /* Do not change these values without updating their counterparts
     * in include/media/mediaplayer2.h!
     */
    /** Unspecified media player info.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_UNKNOWN = 1;

    /** The player switched to this datas source because it is the
     * next-to-be-played in the playlist.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_STARTED_AS_NEXT = 2;

    /** The player just pushed the very first video frame for rendering.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_VIDEO_RENDERING_START = 3;

    /** The player just rendered the very first audio sample.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_AUDIO_RENDERING_START = 4;

    /** The player just completed the playback of this data source.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_PLAYBACK_COMPLETE = 5;

    /** The player just completed the playback of the full playlist.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_PLAYLIST_END = 6;

    /** The player just prepared a data source.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_PREPARED = 100;

    /** The video is too complex for the decoder: it can't decode frames fast
     *  enough. Possibly only the audio plays fine at this stage.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_VIDEO_TRACK_LAGGING = 700;

    /** MediaPlayer2 is temporarily pausing playback internally in order to
     * buffer more data.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_BUFFERING_START = 701;

    /** MediaPlayer2 is resuming playback after filling buffers.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_BUFFERING_END = 702;

    /** Estimated network bandwidth information (kbps) is available; currently this event fires
     * simultaneously as {@link #MEDIA_INFO_BUFFERING_START} and {@link #MEDIA_INFO_BUFFERING_END}
     * when playing network files.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final int MEDIA_INFO_NETWORK_BANDWIDTH = 703;

    /**
     * Update status in buffering a media source received through progressive downloading.
     * The received buffering percentage indicates how much of the content has been buffered
     * or played. For example a buffering update of 80 percent when half the content
     * has already been played indicates that the next 30 percent of the
     * content to play has been buffered.
     *
     * The {@code extra} parameter in {@code MediaPlayer2EventCallback.onInfo} is the
     * percentage (0-100) of the content that has been buffered or played thus far.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_BUFFERING_UPDATE = 704;

    /** Bad interleaving means that a media has been improperly interleaved or
     * not interleaved at all, e.g has all the video samples first then all the
     * audio ones. Video is playing but a lot of disk seeks may be happening.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_BAD_INTERLEAVING = 800;

    /** The media cannot be seeked (e.g live stream)
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_NOT_SEEKABLE = 801;

    /** A new set of metadata is available.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_METADATA_UPDATE = 802;

    /** A new set of external-only metadata is available.  Used by
     *  JAVA framework to avoid triggering track scanning.
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final int MEDIA_INFO_EXTERNAL_METADATA_UPDATE = 803;

    /** Informs that audio is not playing. Note that playback of the video
     * is not interrupted.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_AUDIO_NOT_PLAYING = 804;

    /** Informs that video is not playing. Note that playback of the audio
     * is not interrupted.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_VIDEO_NOT_PLAYING = 805;

    /** Failed to handle timed text track properly.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     * {@hide}
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final int MEDIA_INFO_TIMED_TEXT_ERROR = 900;

    /** Subtitle track was not supported by the media framework.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_UNSUPPORTED_SUBTITLE = 901;

    /** Reading the subtitle track takes too long.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onInfo
     */
    public static final int MEDIA_INFO_SUBTITLE_TIMED_OUT = 902;

    /**
     * @hide
     */
    @IntDef(flag = false, /*prefix = "MEDIA_INFO",*/ value = {
            MEDIA_INFO_UNKNOWN,
            MEDIA_INFO_STARTED_AS_NEXT,
            MEDIA_INFO_VIDEO_RENDERING_START,
            MEDIA_INFO_AUDIO_RENDERING_START,
            MEDIA_INFO_PLAYBACK_COMPLETE,
            MEDIA_INFO_PLAYLIST_END,
            MEDIA_INFO_PREPARED,
            MEDIA_INFO_VIDEO_TRACK_LAGGING,
            MEDIA_INFO_BUFFERING_START,
            MEDIA_INFO_BUFFERING_END,
            MEDIA_INFO_NETWORK_BANDWIDTH,
            MEDIA_INFO_BUFFERING_UPDATE,
            MEDIA_INFO_BAD_INTERLEAVING,
            MEDIA_INFO_NOT_SEEKABLE,
            MEDIA_INFO_METADATA_UPDATE,
            MEDIA_INFO_EXTERNAL_METADATA_UPDATE,
            MEDIA_INFO_AUDIO_NOT_PLAYING,
            MEDIA_INFO_VIDEO_NOT_PLAYING,
            MEDIA_INFO_TIMED_TEXT_ERROR,
            MEDIA_INFO_UNSUPPORTED_SUBTITLE,
            MEDIA_INFO_SUBTITLE_TIMED_OUT
    })
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface MediaInfo {}

    //--------------------------------------------------------------------------
    /** The player just completed a call {@link #attachAuxEffect}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_ATTACH_AUX_EFFECT = 1;

    /** The player just completed a call {@link #deselectTrack}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_DESELECT_TRACK = 2;

    /** The player just completed a call {@link #loopCurrent}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_LOOP_CURRENT = 3;

    /** The player just completed a call {@link #pause}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_PAUSE = 4;

    /** The player just completed a call {@link #play}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_PLAY = 5;

    /** The player just completed a call {@link #prepare}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_PREPARE = 6;

    /** The player just completed a call {@link #releaseDrm}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_RELEASE_DRM = 12;

    /** The player just completed a call {@link #restoreDrmKeys}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_RESTORE_DRM_KEYS = 13;

    /** The player just completed a call {@link #seekTo}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SEEK_TO = 14;

    /** The player just completed a call {@link #selectTrack}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SELECT_TRACK = 15;

    /** The player just completed a call {@link #setAudioAttributes}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_AUDIO_ATTRIBUTES = 16;

    /** The player just completed a call {@link #setAudioSessionId}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_AUDIO_SESSION_ID = 17;

    /** The player just completed a call {@link #setAuxEffectSendLevel}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_AUX_EFFECT_SEND_LEVEL = 18;

    /** The player just completed a call {@link #setDataSource}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_DATA_SOURCE = 19;

    /** The player just completed a call {@link #setNextDataSource}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_NEXT_DATA_SOURCE = 22;

    /** The player just completed a call {@link #setNextDataSources}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_NEXT_DATA_SOURCES = 23;

    /** The player just completed a call {@link #setPlaybackParams}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_PLAYBACK_PARAMS = 24;

    /** The player just completed a call {@link #setPlaybackSpeed}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_PLAYBACK_SPEED = 25;

    /** The player just completed a call {@link #setPlayerVolume}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_PLAYER_VOLUME = 26;

    /** The player just completed a call {@link #setSurface}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_SURFACE = 27;

    /** The player just completed a call {@link #setSyncParams}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SET_SYNC_PARAMS = 28;

    /** The player just completed a call {@link #skipToNext}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_COMPLETED_SKIP_TO_NEXT = 29;

    /** The player just completed a call {@code notifyWhenCommandLabelReached}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCommandLabelReached
     * @hide
     */
    @RestrictTo(LIBRARY_GROUP)
    public static final int CALL_COMPLETED_NOTIFY_WHEN_COMMAND_LABEL_REACHED = 1003;

    /**
     * @hide
     */
    @IntDef(flag = false, /*prefix = "CALL_COMPLETED",*/ value = {
            CALL_COMPLETED_ATTACH_AUX_EFFECT,
            CALL_COMPLETED_DESELECT_TRACK,
            CALL_COMPLETED_LOOP_CURRENT,
            CALL_COMPLETED_PAUSE,
            CALL_COMPLETED_PLAY,
            CALL_COMPLETED_PREPARE,
            CALL_COMPLETED_RELEASE_DRM,
            CALL_COMPLETED_RESTORE_DRM_KEYS,
            CALL_COMPLETED_SEEK_TO,
            CALL_COMPLETED_SELECT_TRACK,
            CALL_COMPLETED_SET_AUDIO_ATTRIBUTES,
            CALL_COMPLETED_SET_AUDIO_SESSION_ID,
            CALL_COMPLETED_SET_AUX_EFFECT_SEND_LEVEL,
            CALL_COMPLETED_SET_DATA_SOURCE,
            CALL_COMPLETED_SET_NEXT_DATA_SOURCE,
            CALL_COMPLETED_SET_NEXT_DATA_SOURCES,
            CALL_COMPLETED_SET_PLAYBACK_PARAMS,
            CALL_COMPLETED_SET_PLAYBACK_SPEED,
            CALL_COMPLETED_SET_PLAYER_VOLUME,
            CALL_COMPLETED_SET_SURFACE,
            CALL_COMPLETED_SET_SYNC_PARAMS,
            CALL_COMPLETED_SKIP_TO_NEXT,
            CALL_COMPLETED_NOTIFY_WHEN_COMMAND_LABEL_REACHED
    })
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface CallCompleted {}

    /** Status code represents that call is completed without an error.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_NO_ERROR = 0;

    /** Status code represents that call is ended with an unknown error.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_ERROR_UNKNOWN = Integer.MIN_VALUE;

    /** Status code represents that the player is not in valid state for the operation.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_INVALID_OPERATION = 1;

    /** Status code represents that the argument is illegal.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_BAD_VALUE = 2;

    /** Status code represents that the operation is not allowed.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_PERMISSION_DENIED = 3;

    /** Status code represents a file or network related operation error.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_ERROR_IO = 4;

    /** Status code represents that DRM operation is called before preparing a DRM scheme through
     *  {@link #prepareDrm}.
     * @see MediaPlayer2.MediaPlayer2EventCallback#onCallCompleted
     */
    public static final int CALL_STATUS_NO_DRM_SCHEME = 5;

    /**
     * @hide
     */
    @IntDef(flag = false, /*prefix = "CALL_STATUS",*/ value = {
            CALL_STATUS_NO_ERROR,
            CALL_STATUS_ERROR_UNKNOWN,
            CALL_STATUS_INVALID_OPERATION,
            CALL_STATUS_BAD_VALUE,
            CALL_STATUS_PERMISSION_DENIED,
            CALL_STATUS_ERROR_IO,
            CALL_STATUS_NO_DRM_SCHEME})
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface CallStatus {}

    // Modular DRM begin

    /**
     * Interface definition of a callback to be invoked when the app
     * can do DRM configuration (get/set properties) before the session
     * is opened. This facilitates configuration of the properties, like
     * 'securityLevel', which has to be set after DRM scheme creation but
     * before the DRM session is opened.
     *
     * The only allowed DRM calls in this listener are {@link #getDrmPropertyString}
     * and {@link #setDrmPropertyString}.
     */
    public interface OnDrmConfigHelper {
        /**
         * Called to give the app the opportunity to configure DRM before the session is created
         *
         * @param mp the {@code MediaPlayer2} associated with this callback
         * @param dsd the DataSourceDesc of this data source
         */
        void onDrmConfig(MediaPlayer2 mp, DataSourceDesc dsd);
    }

    /**
     * Register a callback to be invoked for configuration of the DRM object before
     * the session is created.
     * The callback will be invoked synchronously during the execution
     * of {@link #prepareDrm(UUID uuid)}.
     *
     * @param listener the callback that will be run
     */
    // This is a synchronous call.
    public abstract void setOnDrmConfigHelper(OnDrmConfigHelper listener);

    /**
     * Interface definition for callbacks to be invoked when the player has the corresponding
     * DRM events.
     */
    public abstract static class DrmEventCallback {
        /**
         * Called to indicate DRM info is available
         *
         * @param mp the {@code MediaPlayer2} associated with this callback
         * @param dsd the DataSourceDesc of this data source
         * @param drmInfo DRM info of the source including PSSH, and subset
         *                of crypto schemes supported by this device
         */
        public void onDrmInfo(MediaPlayer2 mp, DataSourceDesc dsd, DrmInfo drmInfo) { }

        /**
         * Called to notify the client that {@link #prepareDrm} is finished and ready for
         * key request/response.
         *
         * @param mp the {@code MediaPlayer2} associated with this callback
         * @param dsd the DataSourceDesc of this data source
         * @param status the result of DRM preparation.
         */
        public void onDrmPrepared(
                MediaPlayer2 mp, DataSourceDesc dsd, @PrepareDrmStatusCode int status) { }
    }

    /**
     * Sets the callback to be invoked when the media source is ready for playback.
     *
     * @param eventCallback the callback that will be run
     * @param executor the executor through which the callback should be invoked
     */
    // This is a synchronous call.
    public abstract void setDrmEventCallback(@NonNull Executor executor,
                                             @NonNull DrmEventCallback eventCallback);

    /**
     * Clears the {@link DrmEventCallback}.
     */
    // This is a synchronous call.
    public abstract void clearDrmEventCallback();

    /**
     * The status codes for {@link DrmEventCallback#onDrmPrepared} listener.
     * <p>
     *
     * DRM preparation has succeeded.
     */
    public static final int PREPARE_DRM_STATUS_SUCCESS = 0;

    /**
     * The device required DRM provisioning but couldn't reach the provisioning server.
     */
    public static final int PREPARE_DRM_STATUS_PROVISIONING_NETWORK_ERROR = 1;

    /**
     * The device required DRM provisioning but the provisioning server denied the request.
     */
    public static final int PREPARE_DRM_STATUS_PROVISIONING_SERVER_ERROR = 2;

    /**
     * The DRM preparation has failed .
     */
    public static final int PREPARE_DRM_STATUS_PREPARATION_ERROR = 3;


    /** @hide */
    @IntDef(flag = false, /*prefix = "PREPARE_DRM_STATUS",*/ value = {
            PREPARE_DRM_STATUS_SUCCESS,
            PREPARE_DRM_STATUS_PROVISIONING_NETWORK_ERROR,
            PREPARE_DRM_STATUS_PROVISIONING_SERVER_ERROR,
            PREPARE_DRM_STATUS_PREPARATION_ERROR,
    })
    @Retention(RetentionPolicy.SOURCE)
    @RestrictTo(LIBRARY_GROUP)
    public @interface PrepareDrmStatusCode {}

    /**
     * Retrieves the DRM Info associated with the current source
     *
     * @throws IllegalStateException if called before being prepared
     */
    public abstract DrmInfo getDrmInfo();

    /**
     * Prepares the DRM for the current source
     * <p>
     * If {@link OnDrmConfigHelper} is registered, it will be called during
     * preparation to allow configuration of the DRM properties before opening the
     * DRM session. Note that the callback is called synchronously in the thread that called
     * {@link #prepareDrm}. It should be used only for a series of {@code getDrmPropertyString}
     * and {@code setDrmPropertyString} calls and refrain from any lengthy operation.
     * <p>
     * If the device has not been provisioned before, this call also provisions the device
     * which involves accessing the provisioning server and can take a variable time to
     * complete depending on the network connectivity.
     * If {@code OnDrmPreparedListener} is registered, prepareDrm() runs in non-blocking
     * mode by launching the provisioning in the background and returning. The listener
     * will be called when provisioning and preparation has finished. If a
     * {@code OnDrmPreparedListener} is not registered, prepareDrm() waits till provisioning
     * and preparation has finished, i.e., runs in blocking mode.
     * <p>
     * If {@code OnDrmPreparedListener} is registered, it is called to indicate the DRM
     * session being ready. The application should not make any assumption about its call
     * sequence (e.g., before or after prepareDrm returns), or the thread context that will
     * execute the listener (unless the listener is registered with a handler thread).
     * <p>
     *
     * @param uuid The UUID of the crypto scheme. If not known beforehand, it can be retrieved
     * from the source through {@code getDrmInfo} or registering a {@code onDrmInfoListener}.
     *
     * @throws IllegalStateException              if called before being prepared or the DRM was
     *                                            prepared already
     * @throws UnsupportedSchemeException         if the crypto scheme is not supported
     * @throws ResourceBusyException              if required DRM resources are in use
     * @throws ProvisioningNetworkErrorException  if provisioning is required but failed due to a
     *                                            network error
     * @throws ProvisioningServerErrorException   if provisioning is required but failed due to
     *                                            the request denied by the provisioning server
     */
    // This is a synchronous call.
    public abstract void prepareDrm(@NonNull UUID uuid)
            throws UnsupportedSchemeException, ResourceBusyException,
            ProvisioningNetworkErrorException, ProvisioningServerErrorException;

    /**
     * Releases the DRM session
     * <p>
     * The player has to have an active DRM session and be in stopped, or prepared
     * state before this call is made.
     * A {@code reset()} call will release the DRM session implicitly.
     *
     * @throws NoDrmSchemeException if there is no active DRM session to release
     */
    // This is an asynchronous call.
    public abstract void releaseDrm() throws NoDrmSchemeException;

    /**
     * A key request/response exchange occurs between the app and a license server
     * to obtain or release keys used to decrypt encrypted content.
     * <p>
     * getDrmKeyRequest() is used to obtain an opaque key request byte array that is
     * delivered to the license server.  The opaque key request byte array is returned
     * in KeyRequest.data.  The recommended URL to deliver the key request to is
     * returned in KeyRequest.defaultUrl.
     * <p>
     * After the app has received the key request response from the server,
     * it should deliver to the response to the DRM engine plugin using the method
     * {@link #provideDrmKeyResponse}.
     *
     * @param keySetId is the key-set identifier of the offline keys being released when keyType is
     * {@link MediaDrm#KEY_TYPE_RELEASE}. It should be set to null for other key requests, when
     * keyType is {@link MediaDrm#KEY_TYPE_STREAMING} or {@link MediaDrm#KEY_TYPE_OFFLINE}.
     *
     * @param initData is the container-specific initialization data when the keyType is
     * {@link MediaDrm#KEY_TYPE_STREAMING} or {@link MediaDrm#KEY_TYPE_OFFLINE}. Its meaning is
     * interpreted based on the mime type provided in the mimeType parameter.  It could
     * contain, for example, the content ID, key ID or other data obtained from the content
     * metadata that is required in generating the key request.
     * When the keyType is {@link MediaDrm#KEY_TYPE_RELEASE}, it should be set to null.
     *
     * @param mimeType identifies the mime type of the content
     *
     * @param keyType specifies the type of the request. The request may be to acquire
     * keys for streaming, {@link MediaDrm#KEY_TYPE_STREAMING}, or for offline content
     * {@link MediaDrm#KEY_TYPE_OFFLINE}, or to release previously acquired
     * keys ({@link MediaDrm#KEY_TYPE_RELEASE}), which are identified by a keySetId.
     *
     * @param optionalParameters are included in the key request message to
     * allow a client application to provide additional message parameters to the server.
     * This may be {@code null} if no additional parameters are to be sent.
     *
     * @throws NoDrmSchemeException if there is no active DRM session
     */
    @NonNull
    public abstract MediaDrm.KeyRequest getDrmKeyRequest(
            @Nullable byte[] keySetId, @Nullable byte[] initData,
            @Nullable String mimeType, int keyType,
            @Nullable Map<String, String> optionalParameters)
            throws NoDrmSchemeException;

    /**
     * A key response is received from the license server by the app, then it is
     * provided to the DRM engine plugin using provideDrmKeyResponse. When the
     * response is for an offline key request, a key-set identifier is returned that
     * can be used to later restore the keys to a new session with the method
     * {@ link # restoreDrmKeys}.
     * When the response is for a streaming or release request, null is returned.
     *
     * @param keySetId When the response is for a release request, keySetId identifies
     * the saved key associated with the release request (i.e., the same keySetId
     * passed to the earlier {@ link # getDrmKeyRequest} call. It MUST be null when the
     * response is for either streaming or offline key requests.
     *
     * @param response the byte array response from the server
     *
     * @throws NoDrmSchemeException if there is no active DRM session
     * @throws DeniedByServerException if the response indicates that the
     * server rejected the request
     */
    // This is a synchronous call.
    public abstract byte[] provideDrmKeyResponse(
            @Nullable byte[] keySetId, @NonNull byte[] response)
            throws NoDrmSchemeException, DeniedByServerException;

    /**
     * Restore persisted offline keys into a new session.  keySetId identifies the
     * keys to load, obtained from a prior call to {@link #provideDrmKeyResponse}.
     *
     * @param keySetId identifies the saved key set to restore
     */
    // This is an asynchronous call.
    public abstract void restoreDrmKeys(@NonNull byte[] keySetId)
            throws NoDrmSchemeException;

    /**
     * Read a DRM engine plugin String property value, given the property name string.
     * <p>
     * @param propertyName the property name
     *
     * Standard fields names are:
     * {@link MediaDrm#PROPERTY_VENDOR}, {@link MediaDrm#PROPERTY_VERSION},
     * {@link MediaDrm#PROPERTY_DESCRIPTION}, {@link MediaDrm#PROPERTY_ALGORITHMS}
     */
    @NonNull
    public abstract String getDrmPropertyString(
            @NonNull String propertyName)
            throws NoDrmSchemeException;

    /**
     * Set a DRM engine plugin String property value.
     * <p>
     * @param propertyName the property name
     * @param value the property value
     *
     * Standard fields names are:
     * {@link MediaDrm#PROPERTY_VENDOR}, {@link MediaDrm#PROPERTY_VERSION},
     * {@link MediaDrm#PROPERTY_DESCRIPTION}, {@link MediaDrm#PROPERTY_ALGORITHMS}
     */
    // This is a synchronous call.
    public abstract void setDrmPropertyString(
            @NonNull String propertyName, @NonNull String value)
            throws NoDrmSchemeException;

    /**
     * Encapsulates the DRM properties of the source.
     */
    public abstract static class DrmInfo {
        /**
         * Returns the PSSH info of the data source for each supported DRM scheme.
         */
        public abstract Map<UUID, byte[]> getPssh();

        /**
         * Returns the intersection of the data source and the device DRM schemes.
         * It effectively identifies the subset of the source's DRM schemes which
         * are supported by the device too.
         */
        public abstract List<UUID> getSupportedSchemes();
    };  // DrmInfo

    /**
     * Thrown when a DRM method is called before preparing a DRM scheme through prepareDrm().
     * Extends MediaDrm.MediaDrmException
     */
    public static class NoDrmSchemeException extends MediaDrmException {
        public NoDrmSchemeException(String detailMessage) {
            super(detailMessage);
        }
    }

    /**
     * Thrown when the device requires DRM provisioning but the provisioning attempt has
     * failed due to a network error (Internet reachability, timeout, etc.).
     * Extends MediaDrm.MediaDrmException
     */
    public static class ProvisioningNetworkErrorException extends MediaDrmException {
        public ProvisioningNetworkErrorException(String detailMessage) {
            super(detailMessage);
        }
    }

    /**
     * Thrown when the device requires DRM provisioning but the provisioning attempt has
     * failed due to the provisioning server denying the request.
     * Extends MediaDrm.MediaDrmException
     */
    public static class ProvisioningServerErrorException extends MediaDrmException {
        public ProvisioningServerErrorException(String detailMessage) {
            super(detailMessage);
        }
    }
}