Only reselect audio streams when user preference is respected (#13832)

MediaBrowser.Model/MediaInfo/AudioIndexSource.cs

@@ -0,0 +1,30 @@
+using System;
+
+namespace MediaBrowser.Model.MediaInfo;
+
+/// <summary>
+/// How is the audio index determined.
+/// </summary>
+[Flags]
+public enum AudioIndexSource
+{
+    /// <summary>
+    /// The default index when no preference is specified.
+    /// </summary>
+    None = 0,
+
+    /// <summary>
+    /// The index is calculated whether the track is marked as default or not.
+    /// </summary>
+    Default = 1 << 0,
+
+    /// <summary>
+    /// The index is calculated whether the track is in preferred language or not.
+    /// </summary>
+    Language = 1 << 1,
+
+    /// <summary>
+    /// The index is specified by the user.
+    /// </summary>
+    User = 1 << 2
+}