2 files changed, 79 insertions, 2 deletions
diff --git a/Jellyfin.Server/Migrations/PreStartupRoutines/MigrateEncodingOptions.cs b/Jellyfin.Server/Migrations/PreStartupRoutines/MigrateEncodingOptions.cs
index 0141b43c96..a5006c9bfa 100644
--- a/Jellyfin.Server/Migrations/PreStartupRoutines/MigrateEncodingOptions.cs
+++ b/Jellyfin.Server/Migrations/PreStartupRoutines/MigrateEncodingOptions.cs
@@ -79,8 +79,8 @@ public class MigrateEncodingOptions : IMigrationRoutine
             tonemappingRange = parsedTonemappingRange;
         }
 
-        var encoderPreset = EncoderPreset.superfast;
-        if (Enum.TryParse<EncoderPreset>(oldConfig.TonemappingRange, true, out var parsedEncoderPreset))
+        var encoderPreset = EncoderPreset.auto;
+        if (Enum.TryParse<EncoderPreset>(oldConfig.EncoderPreset, true, out var parsedEncoderPreset))
         {
             encoderPreset = parsedEncoderPreset;
         }
diff --git a/Jellyfin.Server/Migrations/Routines/20260915104305_FixNullEncoderPreset.cs b/Jellyfin.Server/Migrations/Routines/20260915104305_FixNullEncoderPreset.cs
new file mode 100644
index 0000000000..f8e63f1920
--- /dev/null
+++ b/Jellyfin.Server/Migrations/Routines/20260915104305_FixNullEncoderPreset.cs
@@ -0,0 +1,77 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Xml;
+using System.Xml.Linq;
+using Jellyfin.Server.Migrations.Stages;
+using MediaBrowser.Common.Configuration;
+using MediaBrowser.Model.Configuration;
+using MediaBrowser.Model.Entities;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Server.Migrations.Routines;
+
+/// <summary>
+/// Replaces the nullable encoder preset written by older versions with the default preset.
+/// </summary>
+[JellyfinMigration("2026-09-15T10:43:05", nameof(FixNullEncoderPreset), Stage = JellyfinMigrationStageTypes.PreInitialisation)]
+internal class FixNullEncoderPreset : IAsyncMigrationRoutine
+{
+    private static readonly XNamespace _xsiNamespace = "http://www.w3.org/2001/XMLSchema-instance";
+
+    private readonly IApplicationPaths _applicationPaths;
+    private readonly ILogger<FixNullEncoderPreset> _logger;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FixNullEncoderPreset"/> class.
+    /// </summary>
+    /// <param name="applicationPaths">The application paths.</param>
+    /// <param name="logger">The logger.</param>
+    public FixNullEncoderPreset(IApplicationPaths applicationPaths, ILogger<FixNullEncoderPreset> logger)
+    {
+        _applicationPaths = applicationPaths;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public Task PerformAsync(CancellationToken cancellationToken)
+    {
+        cancellationToken.ThrowIfCancellationRequested();
+
+        var path = Path.Combine(_applicationPaths.ConfigurationDirectoryPath, "encoding.xml");
+        if (!File.Exists(path))
+        {
+            return Task.CompletedTask;
+        }
+
+        XDocument document;
+        try
+        {
+            document = XDocument.Load(path, LoadOptions.PreserveWhitespace);
+        }
+        catch (XmlException ex)
+        {
+            _logger.LogWarning(ex, "Could not parse encoding configuration; skipping null encoder preset migration");
+            return Task.CompletedTask;
+        }
+
+        var encoderPreset = document.Root?.Element(nameof(EncodingOptions.EncoderPreset));
+        if (encoderPreset is null)
+        {
+            return Task.CompletedTask;
+        }
+
+        var nilAttribute = encoderPreset.Attribute(_xsiNamespace + "nil");
+        if (!string.Equals(nilAttribute?.Value, "true", StringComparison.OrdinalIgnoreCase) && !string.IsNullOrEmpty(encoderPreset.Value))
+        {
+            return Task.CompletedTask;
+        }
+
+        nilAttribute?.Remove();
+        encoderPreset.Value = nameof(EncoderPreset.auto);
+        document.Save(path, SaveOptions.DisableFormatting);
+        _logger.LogInformation("Replaced null encoder preset with auto in encoding configuration");
+        return Task.CompletedTask;
+    }
+}