Revert to first approach

osu.Game.Rulesets.Taiko/Beatmaps/TaikoBeatmapConverter.cs

@@ -57,6 +57,29 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
 
             Beatmap<TaikoHitObject> converted = base.ConvertBeatmap(original, cancellationToken);
 
+            if (original.BeatmapInfo.Ruleset.OnlineID == 0)
+            {
+                // Post processing step to transform standard slider velocity changes into scroll speed changes
+                double lastScrollSpeed = 1;
+
+                foreach (HitObject hitObject in original.HitObjects)
+                {
+                    double nextScrollSpeed = hitObject.DifficultyControlPoint.SliderVelocity;
+
+                    if (!Precision.AlmostEquals(lastScrollSpeed, nextScrollSpeed))
+                    {
+                        EffectControlPoint currentControlPoint = converted.ControlPointInfo.EffectPointAt(hitObject.StartTime);
+
+                        if (Precision.AlmostEquals(currentControlPoint.Time, hitObject.StartTime))
+                            currentControlPoint.ScrollSpeed = nextScrollSpeed;
+                        else
+                            converted.ControlPointInfo.Add(hitObject.StartTime, new EffectControlPoint { ScrollSpeed = nextScrollSpeed });
+
+                        lastScrollSpeed = nextScrollSpeed;
+                    }
+                }
+            }
+
             if (original.BeatmapInfo.Ruleset.OnlineID == 3)
             {
                 // Post processing step to transform mania hit objects with the same start time into strong hits

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

@@ -175,7 +175,7 @@ namespace osu.Game.Tests.Beatmaps.Formats
                 Assert.AreEqual(4, controlPoints.TimingPoints.Count);
                 Assert.AreEqual(5, controlPoints.DifficultyPoints.Count);
                 Assert.AreEqual(34, controlPoints.SamplePoints.Count);
-                Assert.AreEqual(13, controlPoints.EffectPoints.Count);
+                Assert.AreEqual(8, controlPoints.EffectPoints.Count);
 
                 var timingPoint = controlPoints.TimingPointAt(0);
                 Assert.AreEqual(956, timingPoint.Time);

osu.Game.Tests/Visual/Editing/TestSceneTimingScreen.cs

@@ -67,8 +67,8 @@ namespace osu.Game.Tests.Visual.Editing
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddUntilStep("Selection changed", () => timingScreen.SelectedGroup.Value.Time == 37560);
+            AddUntilStep("Selection changed", () => timingScreen.SelectedGroup.Value.Time == 54670);
-            AddUntilStep("Ensure seeked to correct time", () => EditorClock.CurrentTimeAccurate == 37560);
+            AddUntilStep("Ensure seeked to correct time", () => EditorClock.CurrentTimeAccurate == 54670);
 
             AddStep("Seek to just before next point", () => EditorClock.Seek(69000));
             AddStep("Start clock", () => EditorClock.Start());
@@ -85,8 +85,8 @@ namespace osu.Game.Tests.Visual.Editing
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddUntilStep("Selection changed", () => timingScreen.SelectedGroup.Value.Time == 37560);
+            AddUntilStep("Selection changed", () => timingScreen.SelectedGroup.Value.Time == 54670);
-            AddUntilStep("Ensure seeked to correct time", () => EditorClock.CurrentTimeAccurate == 37560);
+            AddUntilStep("Ensure seeked to correct time", () => EditorClock.CurrentTimeAccurate == 54670);
 
             AddStep("Seek to later", () => EditorClock.Seek(80000));
             AddUntilStep("Selection changed", () => timingScreen.SelectedGroup.Value.Time == 69670);

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -448,9 +448,14 @@ namespace osu.Game.Beatmaps.Formats
             {
                 KiaiMode = kiaiMode,
                 OmitFirstBarLine = omitFirstBarSignature,
-                ScrollSpeed = speedMultiplier,
             };
 
+            int onlineRulesetID = beatmap.BeatmapInfo.Ruleset.OnlineID;
+
+            // osu!taiko and osu!mania use effect points rather than difficulty points for scroll speed adjustments.
+            if (onlineRulesetID == 1 || onlineRulesetID == 3)
+                effectPoint.ScrollSpeed = speedMultiplier;
+
             addControlPoint(time, effectPoint, timingChange);
 
             addControlPoint(time, new LegacySampleControlPoint

osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs

@@ -10,7 +10,6 @@ using System.IO;
 using System.Linq;
 using System.Text;
 using JetBrains.Annotations;
-using osu.Framework.Utils;
 using osu.Game.Audio;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Beatmaps.Legacy;
@@ -186,17 +185,17 @@ namespace osu.Game.Beatmaps.Formats
             SampleControlPoint lastRelevantSamplePoint = null;
             DifficultyControlPoint lastRelevantDifficultyPoint = null;
 
+            // In osu!taiko and osu!mania, a scroll speed is stored as "slider velocity" in legacy formats.
+            // In that case, a scrolling speed change is a global effect and per-hit object difficulty control points are ignored.
+            bool scrollSpeedEncodedAsSliderVelocity = onlineRulesetID == 1 || onlineRulesetID == 3;
+
             // iterate over hitobjects and pull out all required sample and difficulty changes
             extractDifficultyControlPoints(beatmap.HitObjects);
             extractSampleControlPoints(beatmap.HitObjects);
 
-            foreach (var point in legacyControlPoints.EffectPoints)
+            if (scrollSpeedEncodedAsSliderVelocity)
             {
-                DifficultyControlPoint difficultyPoint = legacyControlPoints.DifficultyPointAt(point.Time);
+                foreach (var point in legacyControlPoints.EffectPoints)
-
-                if (Precision.AlmostEquals(difficultyPoint.SliderVelocity, point.ScrollSpeed, acceptableDifference: point.ScrollSpeedBindable.Precision))
-                    continue;
-
                     legacyControlPoints.Add(point.Time, new DifficultyControlPoint { SliderVelocity = point.ScrollSpeed });
             }
 
@@ -245,6 +244,9 @@ namespace osu.Game.Beatmaps.Formats
 
             IEnumerable<DifficultyControlPoint> collectDifficultyControlPoints(IEnumerable<HitObject> hitObjects)
             {
+                if (scrollSpeedEncodedAsSliderVelocity)
+                    yield break;
+
                 foreach (var hitObject in hitObjects)
                     yield return hitObject.DifficultyControlPoint;
             }