4 files changed, 12 insertions, 12 deletions
diff --git a/src/base/UMusic.pas b/src/base/UMusic.pas
index 5d816c9a..e1184da8 100644
--- a/src/base/UMusic.pas
+++ b/src/base/UMusic.pas
@@ -188,8 +188,8 @@ type
   end;
 
 type
-  TSyncSource = class
-    function GetClock(): real; virtual; abstract;
+  ISyncSource = interface
+    function GetClock(): real;
   end;
 
   TAudioProcessingStream = class;
@@ -250,7 +250,7 @@ type
 
   TAudioPlaybackStream = class(TAudioProcessingStream)
     protected
-      SyncSource: TSyncSource;
+      SyncSource: ISyncSource;
       AvgSyncDiff: double;
       SourceStream: TAudioSourceStream;
 
@@ -282,7 +282,7 @@ type
       procedure AddSoundEffect(Effect: TSoundEffect);    virtual; abstract;
       procedure RemoveSoundEffect(Effect: TSoundEffect); virtual; abstract;
 
-      procedure SetSyncSource(SyncSource: TSyncSource);
+      procedure SetSyncSource(SyncSource: ISyncSource);
       function GetSourceStream(): TAudioSourceStream;
 
       property Status: TStreamStatus read GetStatus;
@@ -364,7 +364,7 @@ type
       procedure SetLoop(Enabled: boolean);
 
       procedure FadeIn(Time: real; TargetVolume: single);
-      procedure SetSyncSource(SyncSource: TSyncSource);
+      procedure SetSyncSource(SyncSource: ISyncSource);
 
       procedure Rewind;
       function  Finished: boolean;
@@ -978,7 +978,7 @@ begin
   Result := SourceStream;
 end;
 
-procedure TAudioPlaybackStream.SetSyncSource(SyncSource: TSyncSource);
+procedure TAudioPlaybackStream.SetSyncSource(SyncSource: ISyncSource);
 begin
   Self.SyncSource := SyncSource;
   AvgSyncDiff := -1;
diff --git a/src/media/UAudioPlaybackBase.pas b/src/media/UAudioPlaybackBase.pas
index de2d5563..228a438f 100644
--- a/src/media/UAudioPlaybackBase.pas
+++ b/src/media/UAudioPlaybackBase.pas
@@ -60,7 +60,7 @@ type
       procedure Stop;
       procedure FadeIn(Time: real; TargetVolume: single);
 
-      procedure SetSyncSource(SyncSource: TSyncSource);
+      procedure SetSyncSource(SyncSource: ISyncSource);
 
       procedure SetPosition(Time: real);
       function  GetPosition: real;
@@ -228,7 +228,7 @@ begin
     MusicStream.Position := Time;
 end;
 
-procedure TAudioPlaybackBase.SetSyncSource(SyncSource: TSyncSource);
+procedure TAudioPlaybackBase.SetSyncSource(SyncSource: ISyncSource);
 begin
   if assigned(MusicStream) then
     MusicStream.SetSyncSource(SyncSource);
diff --git a/src/media/UMedia_dummy.pas b/src/media/UMedia_dummy.pas
index 25e94724..c38a8e60 100644
--- a/src/media/UMedia_dummy.pas
+++ b/src/media/UMedia_dummy.pas
@@ -62,7 +62,7 @@ type
       procedure SetPosition(Time: real);
       function  GetPosition: real;
 
-      procedure SetSyncSource(SyncSource: TSyncSource);
+      procedure SetSyncSource(SyncSource: ISyncSource);
 
       procedure GetFrame(Time: Extended);
       procedure DrawGL(Screen: integer);
@@ -156,7 +156,7 @@ begin
   Result := 0;
 end;
 
-procedure TMedia_dummy.SetSyncSource(SyncSource: TSyncSource);
+procedure TMedia_dummy.SetSyncSource(SyncSource: ISyncSource);
 begin
 end;
 
diff --git a/src/screens/UScreenSing.pas b/src/screens/UScreenSing.pas
index 20f3b15e..0b7dfba4 100644
--- a/src/screens/UScreenSing.pas
+++ b/src/screens/UScreenSing.pas
@@ -53,8 +53,8 @@ uses
   UTime;
 
 type
-  TLyricsSyncSource = class(TSyncSource)
-    function GetClock(): real; override;
+  TLyricsSyncSource = class(TInterfacedObject,ISyncSource)
+    function GetClock(): real;
   end;
 
 type