Merge pull request #22532 from peppy/fix-long-storyboard-outro

Fix storyboard outro time potentially running too long

osu.Game.Tests/Beatmaps/Formats/LegacyStoryboardDecoderTest.cs

@@ -214,7 +214,9 @@ namespace osu.Game.Tests.Beatmaps.Formats
                 Assert.That(oneTime.EndTime, Is.EqualTo(4000 + loop_duration));
 
                 StoryboardSprite manyTimes = background.Elements.OfType<StoryboardSprite>().Single(s => s.Path == "many-times.png");
-                Assert.That(manyTimes.EndTime, Is.EqualTo(9000 + 40 * loop_duration));
+                // It is intentional that we don't consider the loop count (40) as part of the end time calculation to match stable's handling.
+                // If we were to include the loop count, storyboards which loop for stupid long loop counts would continue playing the outro forever.
+                Assert.That(manyTimes.EndTime, Is.EqualTo(9000 + loop_duration));
             }
         }
     }

osu.Game/Storyboards/CommandLoop.cs

@@ -18,7 +18,12 @@ namespace osu.Game.Storyboards
         public readonly int TotalIterations;
 
         public override double StartTime => LoopStartTime + CommandsStartTime;
-        public override double EndTime => StartTime + CommandsDuration * TotalIterations;
+
+        public override double EndTime =>
+            // In an ideal world, we would multiply the command duration by TotalIterations here.
+            // Unfortunately this would clash with how stable handled end times, and results in some storyboards playing outro
+            // sequences for minutes or hours.
+            StartTime + CommandsDuration;
 
         /// <summary>
         /// Construct a new command loop.

osu.Game/Storyboards/CommandTimelineGroup.cs

@@ -84,9 +84,6 @@ namespace osu.Game.Storyboards
         [JsonIgnore]
         public virtual double EndTime => CommandsEndTime;
 
-        [JsonIgnore]
-        public double Duration => EndTime - StartTime;
-
         [JsonIgnore]
         public bool HasCommands
         {