4 files changed, 17 insertions, 20 deletions
diff --git a/Emby.Naming/Audio/AlbumParser.cs b/Emby.Naming/Audio/AlbumParser.cs
index 33f4468d9..23ff8c3fa 100644
--- a/Emby.Naming/Audio/AlbumParser.cs
+++ b/Emby.Naming/Audio/AlbumParser.cs
@@ -1,3 +1,4 @@
+#nullable enable
 #pragma warning disable CS1591
 
 using System;
@@ -22,7 +23,7 @@ namespace Emby.Naming.Audio
         {
             var filename = Path.GetFileName(path);
 
-            if (string.IsNullOrEmpty(filename))
+            if (path.Length == 0)
             {
                 return false;
             }
@@ -39,18 +40,22 @@ namespace Emby.Naming.Audio
             filename = filename.Replace(')', ' ');
             filename = Regex.Replace(filename, @"\s+", " ");
 
-            filename = filename.TrimStart();
+            ReadOnlySpan<char> trimmedFilename = filename.TrimStart();
 
             foreach (var prefix in _options.AlbumStackingPrefixes)
             {
-                if (filename.IndexOf(prefix, StringComparison.OrdinalIgnoreCase) != 0)
+                if (!trimmedFilename.StartsWith(prefix, StringComparison.OrdinalIgnoreCase))
                 {
                     continue;
                 }
 
-                var tmp = filename.Substring(prefix.Length);
+                var tmp = trimmedFilename.Slice(prefix.Length).Trim();
 
-                tmp = tmp.Trim().Split(' ').FirstOrDefault() ?? string.Empty;
+                int index = tmp.IndexOf(' ');
+                if (index != -1)
+                {
+                    tmp = tmp.Slice(0, index);
+                }
 
                 if (int.TryParse(tmp, NumberStyles.Integer, CultureInfo.InvariantCulture, out _))
                 {
diff --git a/Emby.Naming/Audio/AudioFileParser.cs b/Emby.Naming/Audio/AudioFileParser.cs
index 25d5f8735..6b2f4be93 100644
--- a/Emby.Naming/Audio/AudioFileParser.cs
+++ b/Emby.Naming/Audio/AudioFileParser.cs
@@ -1,3 +1,4 @@
+#nullable enable
 #pragma warning disable CS1591
 
 using System;
@@ -11,7 +12,7 @@ namespace Emby.Naming.Audio
     {
         public static bool IsAudioFile(string path, NamingOptions options)
         {
-            var extension = Path.GetExtension(path) ?? string.Empty;
+            var extension = Path.GetExtension(path);
             return options.AudioFileExtensions.Contains(extension, StringComparer.OrdinalIgnoreCase);
         }
     }
diff --git a/Emby.Naming/Common/EpisodeExpression.cs b/Emby.Naming/Common/EpisodeExpression.cs
index 07de72851..ed6ba8881 100644
--- a/Emby.Naming/Common/EpisodeExpression.cs
+++ b/Emby.Naming/Common/EpisodeExpression.cs
@@ -23,11 +23,6 @@ namespace Emby.Naming.Common
         {
         }
 
-        public EpisodeExpression()
-            : this(null)
-        {
-        }
-
         public string Expression
         {
             get => _expression;
@@ -48,6 +43,6 @@ namespace Emby.Naming.Common
 
         public string[] DateTimeFormats { get; set; }
 
-        public Regex Regex => _regex ?? (_regex = new Regex(Expression, RegexOptions.IgnoreCase | RegexOptions.Compiled));
+        public Regex Regex => _regex ??= new Regex(Expression, RegexOptions.IgnoreCase | RegexOptions.Compiled);
     }
 }
diff --git a/Emby.Naming/Subtitles/SubtitleParser.cs b/Emby.Naming/Subtitles/SubtitleParser.cs
index 88ec3e2d6..542584bee 100644
--- a/Emby.Naming/Subtitles/SubtitleParser.cs
+++ b/Emby.Naming/Subtitles/SubtitleParser.cs
@@ -1,3 +1,4 @@
+#nullable enable
 #pragma warning disable CS1591
 
 using System;
@@ -16,11 +17,11 @@ namespace Emby.Naming.Subtitles
             _options = options;
         }
 
-        public SubtitleInfo ParseFile(string path)
+        public SubtitleInfo? ParseFile(string path)
         {
-            if (string.IsNullOrEmpty(path))
+            if (path.Length == 0)
             {
-                throw new ArgumentNullException(nameof(path));
+                throw new ArgumentException("String can't be empty.", nameof(path));
             }
 
             var extension = Path.GetExtension(path);
@@ -52,11 +53,6 @@ namespace Emby.Naming.Subtitles
 
         private string[] GetFlags(string path)
         {
-            if (string.IsNullOrEmpty(path))
-            {
-                throw new ArgumentNullException(nameof(path));
-            }
-
             // Note: the tags need be be surrounded be either a space ( ), hyphen -, dot . or underscore _.
 
             var file = Path.GetFileName(path);