Fix occasional error of audio downloads hanging.

Source/AaxDecrypter/AaxcDownloadConvertBase.cs

@@ -1,5 +1,6 @@
 using AAXClean;
 using System;
+using System.Linq;
 using System.Threading.Tasks;
 
 namespace AaxDecrypter
@@ -33,20 +34,33 @@ namespace AaxDecrypter
 		{
 			if (DownloadOptions.InputType is FileType.Dash)
 			{
+				//We may have multiple keys , so use the key whose key ID matches
+				//the dash files default Key ID.
+				var keyIds = DownloadOptions.DecryptionKeys.Select(k => new Guid(k.KeyPart1, bigEndian: true)).ToArray();
+
 				var dash = new DashFile(InputFileStream);
-				dash.SetDecryptionKey(DownloadOptions.AudibleKey, DownloadOptions.AudibleIV);
+				var kidIndex = Array.IndexOf(keyIds, dash.Tenc.DefaultKID);
+
+				if (kidIndex == -1)
+					throw new InvalidOperationException($"None of the {keyIds.Length} key IDs match the dash file's default KeyID of {dash.Tenc.DefaultKID}");
+
+				DownloadOptions.DecryptionKeys[0] = DownloadOptions.DecryptionKeys[kidIndex];
+				var keyId = DownloadOptions.DecryptionKeys[kidIndex].KeyPart1;
+				var key = DownloadOptions.DecryptionKeys[kidIndex].KeyPart2;
+
+				dash.SetDecryptionKey(keyId, key);
 				return dash;
 			}
 			else if (DownloadOptions.InputType is FileType.Aax)
 			{
 				var aax = new AaxFile(InputFileStream);
-				aax.SetDecryptionKey(DownloadOptions.AudibleKey);
+				aax.SetDecryptionKey(DownloadOptions.DecryptionKeys[0].KeyPart1);
 				return aax;
 			}
 			else if (DownloadOptions.InputType is FileType.Aaxc)
 			{
 				var aax = new AaxFile(InputFileStream);
-				aax.SetDecryptionKey(DownloadOptions.AudibleKey, DownloadOptions.AudibleIV);
+				aax.SetDecryptionKey(DownloadOptions.DecryptionKeys[0].KeyPart1, DownloadOptions.DecryptionKeys[0].KeyPart2);
 				return aax;
 			}
 			else throw new InvalidOperationException($"{nameof(DownloadOptions.InputType)} of '{DownloadOptions.InputType}' is unknown.");

Source/AaxDecrypter/AudiobookDownloadBase.cs

@@ -73,11 +73,16 @@ namespace AaxDecrypter
 			AsyncSteps[$"Cleanup"] = CleanupAsync;
 			(bool success, var elapsed) = await AsyncSteps.RunAsync();
 
+			//Stop the downloader so it doesn't keep running in the background.
+			if (!success)
+				nfsPersister.Dispose();
+
 			await progressTask;
 
 			var speedup = DownloadOptions.RuntimeLength / elapsed;
 			Serilog.Log.Information($"Speedup is {speedup:F0}x realtime.");
 
+			nfsPersister.Dispose();
 			return success;
 
 			async Task reportProgress()
@@ -177,7 +182,7 @@ namespace AaxDecrypter
 
 			FileUtility.SaferDelete(jsonDownloadState);
 
-			if (!string.IsNullOrEmpty(DownloadOptions.AudibleKey) &&
+			if (DownloadOptions.DecryptionKeys != null &&
 				DownloadOptions.RetainEncryptedFile &&
 				DownloadOptions.InputType is AAXClean.FileType fileType)
 			{
@@ -188,17 +193,21 @@ namespace AaxDecrypter
 
 				if (fileType is AAXClean.FileType.Aax)
 				{
-					await File.WriteAllTextAsync(keyPath, $"ActivationBytes={DownloadOptions.AudibleKey}");
+					await File.WriteAllTextAsync(keyPath, $"ActivationBytes={Convert.ToHexString(DownloadOptions.DecryptionKeys[0].KeyPart1)}");
 					aaxPath = Path.ChangeExtension(tempFilePath, ".aax");
 				}
 				else if (fileType is AAXClean.FileType.Aaxc)
 				{
-					await File.WriteAllTextAsync(keyPath, $"Key={DownloadOptions.AudibleKey}{Environment.NewLine}IV={DownloadOptions.AudibleIV}");
+					await File.WriteAllTextAsync(keyPath,
+						$"Key={Convert.ToHexString(DownloadOptions.DecryptionKeys[0].KeyPart1)}{Environment.NewLine}" +
+						$"IV={Convert.ToHexString(DownloadOptions.DecryptionKeys[0].KeyPart2)}");
 					aaxPath = Path.ChangeExtension(tempFilePath, ".aaxc");
 				}
 				else if (fileType is AAXClean.FileType.Dash)
 				{
-					await File.WriteAllTextAsync(keyPath, $"KeyId={DownloadOptions.AudibleKey}{Environment.NewLine}Key={DownloadOptions.AudibleIV}");
+					await File.WriteAllTextAsync(keyPath,
+						$"KeyId={Convert.ToHexString(DownloadOptions.DecryptionKeys[0].KeyPart1)}{Environment.NewLine}" +
+						$"Key={Convert.ToHexString(DownloadOptions.DecryptionKeys[0].KeyPart2)}");
 					aaxPath = Path.ChangeExtension(tempFilePath, ".dash");
 				}
 				else

Source/AaxDecrypter/IDownloadOptions.cs

@@ -2,15 +2,35 @@
 using System;
 using System.Threading.Tasks;
 
+#nullable enable
 namespace AaxDecrypter
 {
-    public interface IDownloadOptions
+    public class KeyData
+    {
+        public byte[] KeyPart1 { get; }
+        public byte[]? KeyPart2 { get; }
+
+        public KeyData(byte[] keyPart1, byte[]? keyPart2 = null)
+        {
+            KeyPart1 = keyPart1;
+            KeyPart2 = keyPart2;
+        }
+
+        public KeyData(string keyPart1, string? keyPart2 = null)
+        {
+            ArgumentNullException.ThrowIfNull(keyPart1, nameof(keyPart1));
+            KeyPart1 = Convert.FromBase64String(keyPart1);
+            if (keyPart2 != null)
+                KeyPart2 = Convert.FromBase64String(keyPart2);
+        }
+	}    
+
+	public interface IDownloadOptions
     {
         event EventHandler<long> DownloadSpeedChanged;
         string DownloadUrl { get; }
         string UserAgent { get; }
-        string AudibleKey { get; }
+		KeyData[]? DecryptionKeys { get; }
-        string AudibleIV { get; }
         TimeSpan RuntimeLength { get; }
         OutputFormat OutputFormat { get; }
         bool TrimOutputToChapterLength { get; }
@@ -21,14 +41,14 @@ namespace AaxDecrypter
         long DownloadSpeedBps { get; }
         ChapterInfo ChapterInfo { get; }
         bool FixupFile { get; }
-		string AudibleProductId { get; }
+		string? AudibleProductId { get; }
-		string Title { get; }
+		string? Title { get; }
-		string Subtitle { get; }
+		string? Subtitle { get; }
-		string Publisher { get; }
+		string? Publisher { get; }
-		string Language { get; }
+		string? Language { get; }
-		string SeriesName { get; }
+		string? SeriesName { get; }
 		float? SeriesNumber { get; }
-		NAudio.Lame.LameConfig LameConfig { get; }
+		NAudio.Lame.LameConfig? LameConfig { get; }
         bool Downsample { get; }
         bool MatchSourceBitrate { get; }
         bool MoveMoovToBeginning { get; }

Source/AaxDecrypter/NetworkFileStream.cs

@@ -110,14 +110,16 @@ namespace AaxDecrypter
 		#region Downloader
 
 		/// <summary> Update the <see cref="Dinah.Core.IO.JsonFilePersister{T}"/>. </summary>
-		private void OnUpdate()
+		private void OnUpdate(bool waitForWrite = false)
 		{
 			try
 			{
-				if (DateTime.UtcNow > NextUpdateTime)
+				if (waitForWrite || DateTime.UtcNow > NextUpdateTime)
 				{
 					Updated?.Invoke(this, EventArgs.Empty);
 					//JsonFilePersister Will not allow update intervals shorter than 100 milliseconds
+					//If an update is called less than 100 ms since the last update, persister will
+					//sleep the thread until 100 ms has elapsed.
 					NextUpdateTime = DateTime.UtcNow.AddMilliseconds(110);
 				}
 			}
@@ -305,7 +307,7 @@ namespace AaxDecrypter
 			finally
 			{
 				_downloadedPiece.Set();
-				OnUpdate();
+				OnUpdate(waitForWrite: true);
 			}
 		}
 
@@ -402,7 +404,7 @@ namespace AaxDecrypter
 				_cancellationSource?.Dispose();
 				_readFile.Dispose();
 				_writeFile.Dispose();
-				OnUpdate();
+				OnUpdate(waitForWrite: true);
 			}
 
 			disposed = true;

Source/AudibleUtilities/Widevine/Cdm.cs

@@ -55,7 +55,7 @@ public class WidevineKey
 		Type = (KeyType)type;
 		Key = key;
 	}
-	public override string ToString() => $"{Convert.ToHexString(Kid.ToByteArray()).ToLower()}:{Convert.ToHexString(Key).ToLower()}";
+	public override string ToString() => $"{Convert.ToHexString(Kid.ToByteArray(bigEndian: true)).ToLower()}:{Convert.ToHexString(Key).ToLower()}";
 }
 
 public partial class Cdm
@@ -192,7 +192,7 @@ public partial class Cdm
 					id = id.Append(new byte[16 - id.Length]);
 				}
 
-				keys[i] = new WidevineKey(new Guid(id), keyContainer.Type, keyBytes);
+				keys[i] = new WidevineKey(new Guid(id,bigEndian: true), keyContainer.Type, keyBytes);
 			}
 			return keys;
 		}

Source/FileLiberator/DownloadOptions.Factory.cs

@@ -41,12 +41,31 @@ public partial class DownloadOptions
 		return options;
 	}
 
-	private static async Task<ContentLicense> ChooseContent(Api api, LibraryBook libraryBook, Configuration config)
+	private class LicenseInfo
+	{
+		public DrmType DrmType { get; }
+		public ContentMetadata ContentMetadata { get; set; }
+		public KeyData[]? DecryptionKeys { get; }
+		public LicenseInfo(ContentLicense license, IEnumerable<KeyData>? keys = null)
+		{
+			DrmType = license.DrmType;
+			ContentMetadata = license.ContentMetadata;
+			DecryptionKeys = keys?.ToArray() ?? ToKeys(license.Voucher);
+		}
+
+		private static KeyData[]? ToKeys(VoucherDtoV10? voucher)
+			=> voucher is null ? null : [new KeyData(voucher.Key, voucher.Iv)];
+	}
+
+	private static async Task<LicenseInfo> ChooseContent(Api api, LibraryBook libraryBook, Configuration config)
 	{
 		var dlQuality = config.FileDownloadQuality == Configuration.DownloadQuality.Normal ? DownloadQuality.Normal : DownloadQuality.High;
 
 		if (!config.UseWidevine || await Cdm.GetCdmAsync() is not Cdm cdm)
-			return await api.GetDownloadLicenseAsync(libraryBook.Book.AudibleProductId, dlQuality);
+		{
+			var license = await api.GetDownloadLicenseAsync(libraryBook.Book.AudibleProductId, dlQuality);
+			return new LicenseInfo(license);
+		}
 
 		try
 		{
@@ -62,6 +81,9 @@ public partial class DownloadOptions
 					config.RequestSpatial,
 					codecChoice);
 
+			if (contentLic.DrmType is not DrmType.Widevine)
+				return new LicenseInfo(contentLic);
+
 			using var client = new HttpClient();
 			using var mpdResponse = await client.GetAsync(contentLic.LicenseResponse);
 			var dash = new MpegDash(mpdResponse.Content.ReadAsStream());
@@ -75,12 +97,7 @@ public partial class DownloadOptions
 			var challenge = session.GetLicenseChallenge(dash);
 			var licenseMessage = await api.WidevineDrmLicense(libraryBook.Book.AudibleProductId, challenge);
 			var keys = session.ParseLicense(licenseMessage);
-			contentLic.Voucher = new VoucherDtoV10()
+			return new LicenseInfo(contentLic, keys.Select(k => new KeyData(k.Kid.ToByteArray(bigEndian: true), k.Key)));
-			{
-				Key = Convert.ToHexStringLower(keys[0].Kid.ToByteArray()),
-				Iv = Convert.ToHexStringLower(keys[0].Key)
-			};
-			return contentLic;
 		}
 		catch (Exception ex)
 		{
@@ -93,41 +110,20 @@ public partial class DownloadOptions
 	}
 
 
-	private static DownloadOptions BuildDownloadOptions(LibraryBook libraryBook, Configuration config, ContentLicense contentLic)
+	private static DownloadOptions BuildDownloadOptions(LibraryBook libraryBook, Configuration config, LicenseInfo licInfo)
 	{
-		//If DrmType is not Adrm or Widevine, the delivered file is an unencrypted mp3.
-		var outputFormat
-			= contentLic.DrmType is not DrmType.Adrm and not DrmType.Widevine ||
-			(config.AllowLibationFixup && config.DecryptToLossy && contentLic.ContentMetadata.ContentReference.Codec != "ac-4")
-			? OutputFormat.Mp3
-			: OutputFormat.M4b;
-
 		long chapterStartMs
 			= config.StripAudibleBrandAudio
-			? contentLic.ContentMetadata.ChapterInfo.BrandIntroDurationMs
+			? licInfo.ContentMetadata.ChapterInfo.BrandIntroDurationMs
 			: 0;
 
-		AAXClean.FileType? inputType
+		var dlOptions = new DownloadOptions(config, libraryBook, licInfo)
-			= contentLic.DrmType is DrmType.Widevine ? AAXClean.FileType.Dash
-			: contentLic.DrmType is DrmType.Adrm && contentLic.Voucher?.Key.Length == 8 && contentLic.Voucher?.Iv == null ? AAXClean.FileType.Aax
-			: contentLic.DrmType is DrmType.Adrm && contentLic.Voucher?.Key.Length == 32 && contentLic.Voucher?.Iv.Length == 32 ? AAXClean.FileType.Aaxc
-			: null;
-
-		var dlOptions = new DownloadOptions(config, libraryBook, contentLic.ContentMetadata.ContentUrl?.OfflineUrl)
 		{
-			AudibleKey = contentLic.Voucher?.Key,
-			AudibleIV = contentLic.Voucher?.Iv,
-			InputType = inputType,
-			OutputFormat = outputFormat,
-			DrmType = contentLic.DrmType,
-			ContentMetadata = contentLic.ContentMetadata,
-			LameConfig = outputFormat == OutputFormat.Mp3 ? GetLameOptions(config) : null,
 			ChapterInfo = new AAXClean.ChapterInfo(TimeSpan.FromMilliseconds(chapterStartMs)),
-			RuntimeLength = TimeSpan.FromMilliseconds(contentLic.ContentMetadata.ChapterInfo.RuntimeLengthMs),
+			RuntimeLength = TimeSpan.FromMilliseconds(licInfo.ContentMetadata.ChapterInfo.RuntimeLengthMs),
 		};
 
-		dlOptions.LibraryBookDto.Codec = contentLic.ContentMetadata.ContentReference.Codec;
+		if (TryGetAudioInfo(licInfo.ContentMetadata.ContentUrl, out int? bitrate, out int? sampleRate, out int? channels))
-		if (TryGetAudioInfo(contentLic.ContentMetadata.ContentUrl, out int? bitrate, out int? sampleRate, out int? channels))
 		{
 			dlOptions.LibraryBookDto.BitRate = bitrate;
 			dlOptions.LibraryBookDto.SampleRate = sampleRate;
@@ -136,7 +132,7 @@ public partial class DownloadOptions
 
 		var titleConcat = config.CombineNestedChapterTitles ? ": " : null;
 		var chapters
-			= flattenChapters(contentLic.ContentMetadata.ChapterInfo.Chapters, titleConcat)
+			= flattenChapters(licInfo.ContentMetadata.ChapterInfo.Chapters, titleConcat)
 			.OrderBy(c => c.StartOffsetMs)
 			.ToList();
 
@@ -152,7 +148,7 @@ public partial class DownloadOptions
 				chapLenMs -= chapterStartMs;
 
 			if (config.StripAudibleBrandAudio && i == chapters.Count - 1)
-				chapLenMs -= contentLic.ContentMetadata.ChapterInfo.BrandOutroDurationMs;
+				chapLenMs -= licInfo.ContentMetadata.ChapterInfo.BrandOutroDurationMs;
 
 			dlOptions.ChapterInfo.AddChapter(chapter.Title, TimeSpan.FromMilliseconds(chapLenMs));
 		}

Source/FileLiberator/DownloadOptions.cs

@@ -9,27 +9,27 @@ using System.IO;
 using ApplicationServices;
 using LibationFileManager.Templates;
 
+#nullable enable
 namespace FileLiberator
 {
 	public partial class DownloadOptions : IDownloadOptions, IDisposable
 	{
-		public event EventHandler<long> DownloadSpeedChanged;
+		public event EventHandler<long>? DownloadSpeedChanged;
 		public LibraryBook LibraryBook { get; }
 		public LibraryBookDto LibraryBookDto { get; }
 		public string DownloadUrl { get; }
-		public string AudibleKey { get; init; }
+		public KeyData[]? DecryptionKeys { get; }
-		public string AudibleIV { get; init; }
+		public required TimeSpan RuntimeLength { get; init; }
-		public TimeSpan RuntimeLength { get; init; }
+		public OutputFormat OutputFormat { get; }
-		public OutputFormat OutputFormat { get; init; }
+		public required ChapterInfo ChapterInfo { get; init; }
-		public ChapterInfo ChapterInfo { get; init; }
 		public string Title => LibraryBook.Book.Title;
 		public string Subtitle => LibraryBook.Book.Subtitle;
 		public string Publisher => LibraryBook.Book.Publisher;
 		public string Language => LibraryBook.Book.Language;
-		public string AudibleProductId => LibraryBookDto.AudibleProductId;
+		public string? AudibleProductId => LibraryBookDto.AudibleProductId;
-		public string SeriesName => LibraryBookDto.FirstSeries?.Name;
+		public string? SeriesName => LibraryBookDto.FirstSeries?.Name;
 		public float? SeriesNumber => LibraryBookDto.FirstSeries?.Number;
-		public NAudio.Lame.LameConfig LameConfig { get; init; }
+		public NAudio.Lame.LameConfig? LameConfig { get; }
 		public string UserAgent => AudibleApi.Resources.Download_User_Agent;
 		public bool TrimOutputToChapterLength => Config.AllowLibationFixup && Config.StripAudibleBrandAudio;
 		public bool StripUnabridged => Config.AllowLibationFixup && Config.StripUnabridged;
@@ -41,15 +41,15 @@ namespace FileLiberator
 		public bool Downsample => Config.AllowLibationFixup && Config.LameDownsampleMono;
 		public bool MatchSourceBitrate => Config.AllowLibationFixup && Config.LameMatchSourceBR && Config.LameTargetBitrate;
 		public bool MoveMoovToBeginning => Config.MoveMoovToBeginning;
-		public AAXClean.FileType? InputType { get; init; }
+		public AAXClean.FileType? InputType { get; }
-		public AudibleApi.Common.DrmType DrmType { get; init; }
+		public AudibleApi.Common.DrmType DrmType { get; }
-		public AudibleApi.Common.ContentMetadata ContentMetadata { get; init; }
+		public AudibleApi.Common.ContentMetadata ContentMetadata { get; }
 
 		public string GetMultipartFileName(MultiConvertFileProperties props)
 		{
 			var baseDir = Path.GetDirectoryName(props.OutputFileName);
 			var extension = Path.GetExtension(props.OutputFileName);
-			return Templates.ChapterFile.GetFilename(LibraryBookDto, props, baseDir, extension);
+			return Templates.ChapterFile.GetFilename(LibraryBookDto, props, baseDir!, extension);
 		}
 
 		public string GetMultipartTitle(MultiConvertFileProperties props)
@@ -92,14 +92,38 @@ namespace FileLiberator
 			GC.SuppressFinalize(this);
 		}
 
-		private DownloadOptions(Configuration config, LibraryBook libraryBook, [System.Diagnostics.CodeAnalysis.NotNull] string downloadUrl)
+		private DownloadOptions(Configuration config, LibraryBook libraryBook, LicenseInfo licInfo)
 		{
 			Config = ArgumentValidator.EnsureNotNull(config, nameof(config));
 			LibraryBook = ArgumentValidator.EnsureNotNull(libraryBook, nameof(libraryBook));
-			DownloadUrl = ArgumentValidator.EnsureNotNullOrEmpty(downloadUrl, nameof(downloadUrl));
-			// no null/empty check for key/iv. unencrypted files do not have them
 
+			ArgumentValidator.EnsureNotNull(licInfo, nameof(licInfo));
+
+			if (licInfo.ContentMetadata.ContentUrl.OfflineUrl is not string licUrl)
+				throw new InvalidDataException("Content license doesn't contain an offline Url");
+
+			DownloadUrl = licUrl;
+			DecryptionKeys = licInfo.DecryptionKeys;
+			DrmType = licInfo.DrmType;
+			ContentMetadata = licInfo.ContentMetadata;
+			InputType
+			= licInfo.DrmType is AudibleApi.Common.DrmType.Widevine ? AAXClean.FileType.Dash
+			: licInfo.DrmType is AudibleApi.Common.DrmType.Adrm && licInfo.DecryptionKeys?.Length == 1 && licInfo.DecryptionKeys[0].KeyPart1.Length == 8 && licInfo.DecryptionKeys[0].KeyPart2 is null ? AAXClean.FileType.Aax
+			: licInfo.DrmType is AudibleApi.Common.DrmType.Adrm && licInfo.DecryptionKeys?.Length == 1 && licInfo.DecryptionKeys[0].KeyPart1.Length == 32 && licInfo.DecryptionKeys[0].KeyPart2?.Length == 32 ? AAXClean.FileType.Aaxc
+			: null;
+
+			//If DrmType is not Adrm or Widevine, the delivered file is an unencrypted mp3.
+			OutputFormat
+				= licInfo.DrmType is not AudibleApi.Common.DrmType.Adrm and not AudibleApi.Common.DrmType.Widevine ||
+				(config.AllowLibationFixup && config.DecryptToLossy && licInfo.ContentMetadata.ContentReference.Codec != Ac4Codec)
+				? OutputFormat.Mp3
+				: OutputFormat.M4b;
+
+			LameConfig = OutputFormat == OutputFormat.Mp3 ? GetLameOptions(config) : null;
+
+			// no null/empty check for key/iv. unencrypted files do not have them
 			LibraryBookDto = LibraryBook.ToDto();
+			LibraryBookDto.Codec = licInfo.ContentMetadata.ContentReference.Codec;
 
 			cancellation =
 				config