src/Tizen.Multimedia.MediaPlayer/Player/Player.cs

   1 /*
   2  * Copyright (c) 2016 Samsung Electronics Co., Ltd All Rights Reserved
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the License);
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an AS IS BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 using System;
  17 using System.Threading.Tasks;
  18 using System.Runtime.InteropServices;
  19 using System.Diagnostics;
  20 using System.IO;
  21 using System.Threading;
  22 using static Interop;
  23
  24 namespace Tizen.Multimedia
  25 {
  26     internal static class PlayerLog
  27     {
  28         internal const string Tag = "Tizen.Multimedia.Player";
  29     }
  30
  31     /// <summary>
  32     /// Provides the ability to control media playback.
  33     /// </summary>
  34     /// <remarks>
  35     /// The player provides functions to play a media content.
  36     /// It also provides functions to adjust the configurations of the player such as playback rate, volume, looping etc.
  37     /// Note that only one video player can be played at one time.
  38     /// </remarks>
  39     public partial class Player : IDisposable, IDisplayable<PlayerErrorCode>
  40     {
  41         private PlayerHandle _handle;
  42
  43         /// <summary>
  44         /// Initializes a new instance of the <see cref="Player"/> class.
  45         /// </summary>
  46         public Player()
  47         {
  48             NativePlayer.Create(out _handle).ThrowIfFailed("Failed to create player");
  49
  50             Debug.Assert(_handle != null);
  51
  52             RetrieveProperties();
  53
  54             if (Features.IsSupported(Features.AudioEffect))
  55             {
  56                 _audioEffect = new AudioEffect(this);
  57             }
  58
  59             if (Features.IsSupported(Features.RawVideo))
  60             {
  61                 RegisterVideoFrameDecodedCallback();
  62             }
  63
  64             DisplaySettings = PlayerDisplaySettings.Create(this);
  65         }
  66
  67         internal void ValidatePlayerState(params PlayerState[] desiredStates)
  68         {
  69             Debug.Assert(desiredStates.Length > 0);
  70
  71             ValidateNotDisposed();
  72
  73             var curState = State;
  74             if (curState.IsAnyOf(desiredStates))
  75             {
  76                 return;
  77             }
  78
  79             throw new InvalidOperationException($"The player is not in a valid state. " +
  80                 $"Current State : { curState }, Valid State : { string.Join(", ", desiredStates) }.");
  81         }
  82
  83         #region Dispose support
  84         private bool _disposed;
  85
  86         /// <summary>
  87         /// Releases all resources used by the current instance.
  88         /// </summary>
  89         public void Dispose()
  90         {
  91             Dispose(true);
  92         }
  93
  94         private void Dispose(bool disposing)
  95         {
  96             if (!_disposed)
  97             {
  98                 ReplaceDisplay(null);
  99
 100                 if (_source != null)
 101                 {
 102                     try
 103                     {
 104                         _source.DetachFrom(this);
 105                     }
 106                     catch (Exception e)
 107                     {
 108                         Log.Error(PlayerLog.Tag, e.ToString());
 109                     }
 110                 }
 111                 _source = null;
 112
 113                 if (_handle != null)
 114                 {
 115                     _handle.Dispose();
 116                 }
 117                 _disposed = true;
 118             }
 119         }
 120
 121         internal void ValidateNotDisposed()
 122         {
 123             if (_disposed)
 124             {
 125                 Log.Warn(PlayerLog.Tag, "player was disposed");
 126                 throw new ObjectDisposedException(nameof(Player));
 127             }
 128         }
 129
 130         internal bool IsDisposed => _disposed;
 131         #endregion
 132
 133         #region Methods
 134
 135         /// <summary>
 136         /// Gets the streaming download progress.
 137         /// </summary>
 138         /// <returns>The <see cref="DownloadProgress"/> containing current download progress.</returns>
 139         /// <remarks>The player must be in the <see cref="PlayerState.Playing"/> or <see cref="PlayerState.Paused"/> state.</remarks>
 140         /// <exception cref="InvalidOperationException">
 141         ///     The player is not streaming.\n
 142         ///     -or-\n
 143         ///     The player is not in the valid state.
 144         ///     </exception>
 145         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 146         public DownloadProgress GetDownloadProgress()
 147         {
 148             ValidatePlayerState(PlayerState.Playing, PlayerState.Paused);
 149
 150             int start = 0;
 151             int current = 0;
 152             NativePlayer.GetStreamingDownloadProgress(Handle, out start, out current).
 153                 ThrowIfFailed("Failed to get download progress");
 154
 155             Log.Info(PlayerLog.Tag, "get download progress : " + start + ", " + current);
 156
 157             return new DownloadProgress(start, current);
 158         }
 159
 160         /// <summary>
 161         /// Sets the subtitle path for playback.
 162         /// </summary>
 163         /// <remarks>Only MicroDVD/SubViewer(*.sub), SAMI(*.smi), and SubRip(*.srt) subtitle formats are supported.
 164         ///     <para>The mediastorage privilege(http://tizen.org/privilege/mediastorage) must be added if any files are used to play located in the internal storage.
 165         ///     The externalstorage privilege(http://tizen.org/privilege/externalstorage) must be added if any files are used to play located in the external storage.</para>
 166         /// </remarks>
 167         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 168         /// <exception cref="ArgumentException"><paramref name="path"/> is an empty string.</exception>
 169         /// <exception cref="FileNotFoundException">The specified path does not exist.</exception>
 170         /// <exception cref="ArgumentNullException">The path is null.</exception>
 171         public void SetSubtitle(string path)
 172         {
 173             ValidateNotDisposed();
 174
 175             if (path == null)
 176             {
 177                 throw new ArgumentNullException(nameof(path));
 178             }
 179
 180             if (path.Length == 0)
 181             {
 182                 throw new ArgumentException("The path is empty.", nameof(path));
 183             }
 184
 185             if (!File.Exists(path))
 186             {
 187                 throw new FileNotFoundException($"The specified file does not exist.", path);
 188             }
 189
 190             NativePlayer.SetSubtitlePath(Handle, path).
 191                 ThrowIfFailed("Failed to set the subtitle path to the player");
 192         }
 193
 194         /// <summary>
 195         /// Removes the subtitle path.
 196         /// </summary>
 197         /// <remarks>The player must be in the <see cref="PlayerState.Idle"/> state.</remarks>
 198         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 199         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 200         public void ClearSubtitle()
 201         {
 202             ValidatePlayerState(PlayerState.Idle);
 203
 204             NativePlayer.SetSubtitlePath(Handle, null).
 205                 ThrowIfFailed("Failed to clear the subtitle of the player");
 206         }
 207
 208         /// <summary>
 209         /// Sets the offset for the subtitle.
 210         /// </summary>
 211         /// <param name="offset">The value indicating a desired offset in milliseconds.</param>
 212         /// <remarks>The player must be in the <see cref="PlayerState.Playing"/> or <see cref="PlayerState.Paused"/> state.</remarks>
 213         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 214         /// <exception cref="InvalidOperationException">
 215         ///     The player is not in the valid state.\n
 216         ///     -or-\n
 217         ///     No subtitle is set.
 218         /// </exception>
 219         /// <seealso cref="SetSubtitle(string)"/>
 220         public void SetSubtitleOffset(int offset)
 221         {
 222             ValidatePlayerState(PlayerState.Playing, PlayerState.Paused);
 223
 224             var err = NativePlayer.SetSubtitlePositionOffset(Handle, offset);
 225
 226             if (err == PlayerErrorCode.FeatureNotSupported)
 227             {
 228                 throw new InvalidOperationException("No subtitle set");
 229             }
 230
 231             err.ThrowIfFailed("Failed to the subtitle offset of the player");
 232         }
 233
 234         private void Prepare()
 235         {
 236             NativePlayer.Prepare(Handle).ThrowIfFailed("Failed to prepare the player");
 237         }
 238
 239         /// <summary>
 240         /// Called when the <see cref="Prepare"/> is invoked.
 241         /// </summary>
 242         protected virtual void OnPreparing()
 243         {
 244             RegisterEvents();
 245         }
 246
 247         /// <summary>
 248         /// Prepares the media player for playback, asynchronously.
 249         /// </summary>
 250         /// <returns>A task that represents the asynchronous prepare operation.</returns>
 251         /// <remarks>To prepare the player, the player must be in the <see cref="PlayerState.Idle"/> state,
 252         ///     and a source must be set.</remarks>
 253         /// <exception cref="InvalidOperationException">No source is set.</exception>
 254         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 255         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 256         public virtual Task PrepareAsync()
 257         {
 258             if (_source == null)
 259             {
 260                 throw new InvalidOperationException("No source is set.");
 261             }
 262
 263             ValidatePlayerState(PlayerState.Idle);
 264
 265             OnPreparing();
 266
 267             var completionSource = new TaskCompletionSource<bool>();
 268
 269             SetPreparing();
 270
 271             Task.Run(() =>
 272             {
 273                 try
 274                 {
 275                     Prepare();
 276                     ClearPreparing();
 277                     completionSource.SetResult(true);
 278                 }
 279                 catch (Exception e)
 280                 {
 281                     ClearPreparing();
 282                     completionSource.TrySetException(e);
 283                 }
 284             });
 285
 286             return completionSource.Task;
 287         }
 288
 289         /// <summary>
 290         /// Unprepares the player.
 291         /// </summary>
 292         /// <remarks>
 293         ///     The most recently used source is reset and is no longer associated with the player. Playback is no longer possible.
 294         ///     If you want to use the player again, you have to set a source and call <see cref="PrepareAsync"/> again.
 295         ///     <para>
 296         ///     The player must be in the <see cref="PlayerState.Ready"/>, <see cref="PlayerState.Playing"/>, or <see cref="PlayerState.Paused"/> state.
 297         ///     It has no effect if the player is already in the <see cref="PlayerState.Idle"/> state.
 298         ///     </para>
 299         /// </remarks>
 300         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 301         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 302         public virtual void Unprepare()
 303         {
 304             if (State == PlayerState.Idle)
 305             {
 306                 Log.Warn(PlayerLog.Tag, "idle state already");
 307                 return;
 308             }
 309             ValidatePlayerState(PlayerState.Ready, PlayerState.Paused, PlayerState.Playing);
 310
 311             NativePlayer.Unprepare(Handle).ThrowIfFailed("Failed to unprepare the player");
 312
 313             OnUnprepared();
 314         }
 315
 316         /// <summary>
 317         /// Called after the <see cref="Player"/> is unprepared.
 318         /// </summary>
 319         /// <seealso cref="Unprepare"/>
 320         protected virtual void OnUnprepared()
 321         {
 322             _source?.DetachFrom(this);
 323             _source = null;
 324         }
 325
 326         /// <summary>
 327         /// Starts or resumes playback.
 328         /// </summary>
 329         /// <remarks>
 330         /// The player must be in the <see cref="PlayerState.Ready"/> or <see cref="PlayerState.Paused"/> state.
 331         /// It has no effect if the player is already in the <see cref="PlayerState.Playing"/> state.\n
 332         /// \n
 333         /// Sound can be mixed with other sounds if you don't control the stream focus using <see cref="ApplyAudioStreamPolicy"/>.
 334         /// </remarks>
 335         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 336         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 337         /// <seealso cref="PrepareAsync"/>
 338         /// <seealso cref="Stop"/>
 339         /// <seealso cref="Pause"/>
 340         /// <seealso cref="PlaybackCompleted"/>
 341         /// <seealso cref="ApplyAudioStreamPolicy"/>
 342         public virtual void Start()
 343         {
 344             if (State == PlayerState.Playing)
 345             {
 346                 Log.Warn(PlayerLog.Tag, "playing state already");
 347                 return;
 348             }
 349             ValidatePlayerState(PlayerState.Ready, PlayerState.Paused);
 350
 351             NativePlayer.Start(Handle).ThrowIfFailed("Failed to start the player");
 352         }
 353
 354         /// <summary>
 355         /// Stops playing the media content.
 356         /// </summary>
 357         /// <remarks>
 358         /// The player must be in the <see cref="PlayerState.Playing"/> or <see cref="PlayerState.Paused"/> state.
 359         /// It has no effect if the player is already in the <see cref="PlayerState.Ready"/> state.
 360         /// </remarks>
 361         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 362         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 363         /// <seealso cref="Start"/>
 364         /// <seealso cref="Pause"/>
 365         public virtual void Stop()
 366         {
 367             if (State == PlayerState.Ready)
 368             {
 369                 Log.Warn(PlayerLog.Tag, "ready state already");
 370                 return;
 371             }
 372             ValidatePlayerState(PlayerState.Paused, PlayerState.Playing);
 373
 374             NativePlayer.Stop(Handle).ThrowIfFailed("Failed to stop the player");
 375         }
 376
 377         /// <summary>
 378         /// Pauses the player.
 379         /// </summary>
 380         /// <remarks>
 381         /// The player must be in the <see cref="PlayerState.Playing"/> state.
 382         /// It has no effect if the player is already in the <see cref="PlayerState.Paused"/> state.
 383         /// </remarks>
 384         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 385         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 386         /// <seealso cref="Start"/>
 387         public virtual void Pause()
 388         {
 389             if (State == PlayerState.Paused)
 390             {
 391                 Log.Warn(PlayerLog.Tag, "pause state already");
 392                 return;
 393             }
 394
 395             ValidatePlayerState(PlayerState.Playing);
 396
 397             NativePlayer.Pause(Handle).ThrowIfFailed("Failed to pause the player");
 398         }
 399
 400         private MediaSource _source;
 401
 402         /// <summary>
 403         /// Sets a media source for the player.
 404         /// </summary>
 405         /// <param name="source">A <see cref="MediaSource"/> that specifies the source for playback.</param>
 406         /// <remarks>The player must be in the <see cref="PlayerState.Idle"/> state.</remarks>
 407         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 408         /// <exception cref="InvalidOperationException">
 409         ///     The player is not in the valid state.\n
 410         ///     -or-\n
 411         ///     It is not able to assign the source to the player.
 412         ///     </exception>
 413         /// <seealso cref="PrepareAsync"/>
 414         public void SetSource(MediaSource source)
 415         {
 416             ValidatePlayerState(PlayerState.Idle);
 417
 418             if (source != null)
 419             {
 420                 source.AttachTo(this);
 421             }
 422
 423             if (_source != null)
 424             {
 425                 _source.DetachFrom(this);
 426             }
 427
 428             _source = source;
 429         }
 430
 431         /// <summary>
 432         /// Captures a video frame, asynchronously.
 433         /// </summary>
 434         /// <returns>A task that represents the asynchronous capture operation.</returns>
 435         /// <feature>http://tizen.org/feature/multimedia.raw_video</feature>
 436         /// <remarks>The player must be in the <see cref="PlayerState.Playing"/> or <see cref="PlayerState.Paused"/> state.</remarks>
 437         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 438         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 439         /// <exception cref="NotSupportedException">The required feature is not supported.</exception>
 440         public async Task<CapturedFrame> CaptureVideoAsync()
 441         {
 442             ValidationUtil.ValidateFeatureSupported(Features.RawVideo);
 443
 444             ValidatePlayerState(PlayerState.Playing, PlayerState.Paused);
 445
 446             TaskCompletionSource<CapturedFrame> t = new TaskCompletionSource<CapturedFrame>();
 447
 448             NativePlayer.VideoCaptureCallback cb = (data, width, height, size, _) =>
 449             {
 450                 Debug.Assert(size <= int.MaxValue);
 451
 452                 byte[] buf = new byte[size];
 453                 Marshal.Copy(data, buf, 0, (int)size);
 454
 455                 t.TrySetResult(new CapturedFrame(buf, width, height));
 456             };
 457
 458             using (var cbKeeper = ObjectKeeper.Get(cb))
 459             {
 460                 NativePlayer.CaptureVideo(Handle, cb)
 461                     .ThrowIfFailed("Failed to capture the video");
 462
 463                 return await t.Task;
 464             }
 465         }
 466
 467         /// <summary>
 468         /// Gets the play position in milliseconds.
 469         /// </summary>
 470         /// <remarks>The player must be in the <see cref="PlayerState.Ready"/>, <see cref="PlayerState.Playing"/>,
 471         /// or <see cref="PlayerState.Paused"/> state.</remarks>
 472         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 473         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 474         /// <seealso cref="SetPlayPositionAsync(int, bool)"/>
 475         public int GetPlayPosition()
 476         {
 477             ValidatePlayerState(PlayerState.Ready, PlayerState.Paused, PlayerState.Playing);
 478
 479             int playPosition = 0;
 480
 481             NativePlayer.GetPlayPosition(Handle, out playPosition).
 482                 ThrowIfFailed("Failed to get the play position of the player");
 483
 484             Log.Info(PlayerLog.Tag, "get play position : " + playPosition);
 485
 486             return playPosition;
 487         }
 488
 489         private void SetPlayPosition(int milliseconds, bool accurate,
 490             NativePlayer.SeekCompletedCallback cb)
 491         {
 492             var ret = NativePlayer.SetPlayPosition(Handle, milliseconds, accurate, cb, IntPtr.Zero);
 493
 494             //Note that we assume invalid param error is returned only when the position value is invalid.
 495             if (ret == PlayerErrorCode.InvalidArgument)
 496             {
 497                 throw new ArgumentOutOfRangeException(nameof(milliseconds), milliseconds,
 498                     "The position is not valid.");
 499             }
 500             if (ret != PlayerErrorCode.None)
 501             {
 502                 Log.Error(PlayerLog.Tag, "Failed to set play position, " + (PlayerError)ret);
 503             }
 504             ret.ThrowIfFailed("Failed to set play position");
 505         }
 506
 507         /// <summary>
 508         /// Sets the seek position for playback, asynchronously.
 509         /// </summary>
 510         /// <param name="position">The value indicating a desired position in milliseconds.</param>
 511         /// <param name="accurate">The value indicating whether the operation performs with accuracy.</param>
 512         /// <remarks>
 513         ///     <para>The player must be in the <see cref="PlayerState.Ready"/>, <see cref="PlayerState.Playing"/>,
 514         ///     or <see cref="PlayerState.Paused"/> state.</para>
 515         ///     <para>If the <paramref name="accurate"/> is true, the play position will be adjusted as the specified <paramref name="position"/> value,
 516         ///     but this might be considerably slow. If false, the play position will be a nearest keyframe position.</para>
 517         ///     </remarks>
 518         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 519         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 520         /// <exception cref="ArgumentOutOfRangeException">The specified position is not valid.</exception>
 521         /// <seealso cref="GetPlayPosition"/>
 522         public async Task SetPlayPositionAsync(int position, bool accurate)
 523         {
 524             ValidatePlayerState(PlayerState.Ready, PlayerState.Playing, PlayerState.Paused);
 525
 526             var taskCompletionSource = new TaskCompletionSource<bool>();
 527
 528             bool immediateResult = _source is MediaStreamSource;
 529
 530             NativePlayer.SeekCompletedCallback cb = _ => taskCompletionSource.TrySetResult(true);
 531
 532             using (var cbKeeper = ObjectKeeper.Get(cb))
 533             {
 534                 SetPlayPosition(position, accurate, cb);
 535                 if (immediateResult)
 536                 {
 537                     taskCompletionSource.TrySetResult(true);
 538                 }
 539
 540                 await taskCompletionSource.Task;
 541             }
 542         }
 543
 544         /// <summary>
 545         /// Sets the playback rate.
 546         /// </summary>
 547         /// <param name="rate">The value for the playback rate. Valid range is -5.0 to 5.0, inclusive.</param>
 548         /// <remarks>
 549         ///     <para>The player must be in the <see cref="PlayerState.Ready"/>, <see cref="PlayerState.Playing"/>,
 550         ///     or <see cref="PlayerState.Paused"/> state.</para>
 551         ///     <para>The sound will be muted, when the playback rate is under 0.0 or over 2.0.</para>
 552         /// </remarks>
 553         /// <exception cref="ObjectDisposedException">The player has already been disposed of.</exception>
 554         /// <exception cref="InvalidOperationException">
 555         ///     The player is not in the valid state.\n
 556         ///     -or-\n
 557         ///     Streaming playback.
 558         /// </exception>
 559         /// <exception cref="ArgumentOutOfRangeException">
 560         ///     <paramref name="rate"/> is less than 5.0.\n
 561         ///     -or-\n
 562         ///     <paramref name="rate"/> is greater than 5.0.\n
 563         ///     -or-\n
 564         ///     <paramref name="rate"/> is zero.
 565         /// </exception>
 566         public void SetPlaybackRate(float rate)
 567         {
 568             if (rate < -5.0F || 5.0F < rate || rate == 0.0F)
 569             {
 570                 throw new ArgumentOutOfRangeException(nameof(rate), rate, "Valid range is -5.0 to 5.0 (except 0.0)");
 571             }
 572
 573             ValidatePlayerState(PlayerState.Ready, PlayerState.Playing, PlayerState.Paused);
 574
 575             NativePlayer.SetPlaybackRate(Handle, rate).ThrowIfFailed("Failed to set the playback rate.");
 576         }
 577
 578         /// <summary>
 579         /// Applies the audio stream policy.
 580         /// </summary>
 581         /// <param name="policy">The <see cref="AudioStreamPolicy"/> to apply.</param>
 582         /// <remarks>
 583         /// The player must be in the <see cref="PlayerState.Idle"/> state.\n
 584         /// \n
 585         /// <see cref="Player"/> does not support all <see cref="AudioStreamType"/>.\n
 586         /// Supported types are <see cref="AudioStreamType.Media"/>, <see cref="AudioStreamType.System"/>,
 587         /// <see cref="AudioStreamType.Alarm"/>, <see cref="AudioStreamType.Notification"/>,
 588         /// <see cref="AudioStreamType.Emergency"/>, <see cref="AudioStreamType.VoiceInformation"/>,
 589         /// <see cref="AudioStreamType.RingtoneVoip"/> and <see cref="AudioStreamType.MediaExternalOnly"/>.
 590         /// </remarks>
 591         /// <exception cref="ObjectDisposedException">
 592         ///     The player has already been disposed of.\n
 593         ///     -or-\n
 594         ///     <paramref name="policy"/> has already been disposed of.
 595         /// </exception>
 596         /// <exception cref="InvalidOperationException">The player is not in the valid state.</exception>
 597         /// <exception cref="ArgumentNullException"><paramref name="policy"/> is null.</exception>
 598         /// <exception cref="NotSupportedException">
 599         ///     <see cref="AudioStreamType"/> of <paramref name="policy"/> is not supported by <see cref="Player"/>.
 600         /// </exception>
 601         /// <seealso cref="AudioStreamPolicy"/>
 602         public void ApplyAudioStreamPolicy(AudioStreamPolicy policy)
 603         {
 604             if (policy == null)
 605             {
 606                 throw new ArgumentNullException(nameof(policy));
 607             }
 608
 609             ValidatePlayerState(PlayerState.Idle);
 610
 611             NativePlayer.SetAudioPolicyInfo(Handle, policy.Handle).
 612                 ThrowIfFailed("Failed to set the audio stream policy to the player");
 613         }
 614         #endregion
 615
 616         #region Preparing state
 617
 618         private int _isPreparing;
 619
 620         private bool IsPreparing()
 621         {
 622             return Interlocked.CompareExchange(ref _isPreparing, 1, 1) == 1;
 623         }
 624
 625         private void SetPreparing()
 626         {
 627             Interlocked.Exchange(ref _isPreparing, 1);
 628         }
 629
 630         private void ClearPreparing()
 631         {
 632             Interlocked.Exchange(ref _isPreparing, 0);
 633         }
 634
 635         #endregion
 636
 637         /// <summary>
 638         /// This method supports the product infrastructure and is not intended to be used directly from application code.
 639         /// </summary>
 640         protected static Exception GetException(int errorCode, string message) =>
 641             ((PlayerErrorCode)errorCode).GetException(message);
 642     }
 643 }