Handle by clamping `PlaybackPosition` rather than early returning

osu.Framework.Tests/Visual/Sprites/TestSceneVideo.cs

···
             AddUntilStep("decoding ran", () => didDecode);
         }
 
-        [Test]
-        public void TestDecodingContinuesBeforeStartTimeIfLooping()
+        [TestCase(false)]
+        [TestCase(true)]
+        public void TestDecodingStopsBeforeStartTime(bool looping)
         {
-            AddStep("Set looping", () => video.Loop = true);
-
-            AddStep("Jump back to before start time", () => clock.CurrentTime = -30000);
-
-            AddStep("reset decode state", () => didDecode = false);
-            AddUntilStep("decoding ran", () => didDecode);
-        }
+            AddStep("Set looping", () => video.Loop = looping);
 
-        [Test]
-        public void TestDecodingStopsBeforeStartTime()
-        {
             AddStep("Jump back to before start time", () => clock.CurrentTime = -30000);
 
             AddUntilStep("decoding stopped", () => video.State == VideoDecoder.DecoderState.Ready);

osu.Framework/Graphics/Animations/AnimationClockComposite.cs

···
         {
             get
             {
-                if (Loop)
-                    return manualClock.CurrentTime % Duration;
+                double current = manualClock.CurrentTime;
+
+                if (Loop) current %= Duration;
 
-                return Math.Min(manualClock.CurrentTime, Duration);
+                return Math.Clamp(current, 0, Duration);
             }
             set
             {

osu.Framework/Graphics/Video/Video.cs

···
                 }
             }
 
-            // if not looping and not yet having reached the start of the video, don't attempt to consume frames yet.
-            // if we begin consuming frames the decoder will be performing unnecessary work.
-            if (!Loop && PlaybackPosition < 0)
-                return;
-
             var peekFrame = availableFrames.Count > 0 ? availableFrames.Peek() : null;
             bool outOfSync = false;