diff --git a/LibSidWiz/MultiDumperWrapper.cs b/LibSidWiz/MultiDumperWrapper.cs
index 151ad19..626650d 100644
--- a/LibSidWiz/MultiDumperWrapper.cs
+++ b/LibSidWiz/MultiDumperWrapper.cs
@@ -50,22 +50,7 @@ public IEnumerable<Song> GetSongs(string filename)
                 throw new FileNotFoundException("Cannot find VGM file", filename);
             }
 
-            string json;
-            using (var p = new ProcessWrapper(
-                _multiDumperPath,
-                $"\"{filename}\" --json"))
-            {
-                json = string.Join("", p.Lines());
-                // Try to decode any UTF-8 in there
-                try
-                {
-                    json = Encoding.UTF8.GetString(Encoding.Default.GetBytes(json));
-                }
-                catch (Exception)
-                {
-                    // Ignore it, use unfixed string
-                }
-            }
+            var json = GetOutputText($"\"{filename}\" --json", false);
 
             if (string.IsNullOrEmpty(json))
             {
@@ -119,13 +104,43 @@ public IEnumerable<Song> GetSongs(string filename)
                 Game = Clean(metadata.containerinfo.game),
                 System = Clean(metadata.containerinfo.system)
             });
-        }   
+        }
+
+        private string GetOutputText(string args, bool includeStdErr)
+        {
+            using (var p = new ProcessWrapper(
+                _multiDumperPath,
+                args,
+                includeStdErr))
+            {
+                string text = string.Join("", p.Lines());
+                // Try to decode any UTF-8 in there
+                try
+                {
+                    text = Encoding.UTF8.GetString(Encoding.Default.GetBytes(text));
+                }
+                catch (Exception)
+                {
+                    // Ignore it, use unfixed string
+                }
+                return text;
+            }
+        }
 
         public IEnumerable<string> Dump(Song song, Action<double> onProgress)
         {
+            // We check the help first to check for allowed parameters
+            var helpText = GetOutputText("", true);
+
+            var args = new StringBuilder($"\"{song.Filename}\" {song.Index}");
+            if (helpText.Contains("--sampling_rate="))
+            {
+                args.Append($" --sampling_rate={_samplingRate}");
+            }
+
             _processWrapper = new ProcessWrapper(
                 _multiDumperPath,
-                $"\"{song.Filename}\" {song.Index} --sampling_rate={_samplingRate}");
+                args.ToString());
             var progressParts = Enumerable.Repeat(0.0, song.Channels.Count).ToList();
             var r = new Regex(@"(?<channel>\d+)\|(?<position>\d+)\|(?<total>\d+)");
             var stopwatch = Stopwatch.StartNew();
diff --git a/LibSidWiz/ProcessWrapper.cs b/LibSidWiz/ProcessWrapper.cs
index b0750a7..9bd8d48 100644
--- a/LibSidWiz/ProcessWrapper.cs
+++ b/LibSidWiz/ProcessWrapper.cs
@@ -12,7 +12,7 @@ public class ProcessWrapper: IDisposable
         private readonly BlockingCollection<string> _lines = new BlockingCollection<string>(new ConcurrentQueue<string>());
         private readonly CancellationTokenSource _cancellationTokenSource;
 
-        public ProcessWrapper(string filename, string arguments)
+        public ProcessWrapper(string filename, string arguments, bool captureStdErr = false)
         {
             _cancellationTokenSource = new CancellationTokenSource();
 
@@ -23,6 +23,7 @@ public ProcessWrapper(string filename, string arguments)
                     FileName = filename,
                     Arguments = arguments,
                     RedirectStandardOutput = true,
+                    RedirectStandardError = true,
                     UseShellExecute = false,
                     CreateNoWindow = true
                 },
@@ -32,22 +33,33 @@ public ProcessWrapper(string filename, string arguments)
             {
                 throw new Exception($"Error running {filename} {arguments}");
             }
-            _process.OutputDataReceived += (sender, e) =>
+            _process.OutputDataReceived += OnText;
+            if (captureStdErr)
             {
-                if (!_cancellationTokenSource.IsCancellationRequested)
-                {
-                    try
-                    {
-                        _lines.TryAdd(e.Data, 0, _cancellationTokenSource.Token);
-                    }
-                    catch (OperationCanceledException)
-                    {
-                        // Discard it
-                    }
-                }
-            };
+                _process.ErrorDataReceived += OnText;
+            }
             _process.Start();
             _process.BeginOutputReadLine();
+            if (captureStdErr)
+            {
+                _process.BeginErrorReadLine();
+            }
+        }
+
+        private void OnText(object sender, DataReceivedEventArgs e)
+        {
+            if (_cancellationTokenSource.IsCancellationRequested)
+            {
+                return;
+            }
+            try
+            {
+                _lines.TryAdd(e.Data, 0, _cancellationTokenSource.Token);
+            }
+            catch (OperationCanceledException)
+            {
+                // Discard it
+            }
         }
 
         /// <summary>