#1633 fix the degradation

Author: shogo4405

HaishinKit/Sources/Screen/ScreenObject.swift

@@ -250,12 +250,14 @@ public final class VideoTrackScreenObject: ScreenObject, ChromaKeyProcessable {
     /// Create a screen object.
     override public init() {
         super.init()
-        horizontalAlignment = .center
         do {
             queue = try TypedBlockQueue(capacity: Self.capacity, handlers: .outputPTSSortedSampleBuffers)
         } catch {
             logger.error(error)
         }
+        Task {
+            horizontalAlignment = .center
+        }
     }
 
     /// Registers a video effect.