diff --git a/FFMpegCore/Extend/TimeSpanExtensions.cs b/FFMpegCore/Extend/TimeSpanExtensions.cs
index 2d69237..3e70d5c 100644
--- a/FFMpegCore/Extend/TimeSpanExtensions.cs
+++ b/FFMpegCore/Extend/TimeSpanExtensions.cs
@@ -10,6 +10,6 @@ public static string ToLongString(this TimeSpan timeSpan)
             hours += timeSpan.Days * 24;
         }
 
-        return $"-ss {hours:00}:{timeSpan.Minutes:00}:{timeSpan.Seconds:00}.{timeSpan.Milliseconds:000}";
+        return $"{hours:00}:{timeSpan.Minutes:00}:{timeSpan.Seconds:00}.{timeSpan.Milliseconds:000}";
     }
 }