# automaticallyRunsDeferredStart A Boolean value that indicates whether deferred start runs automatically. ``` var automaticallyRunsDeferredStart: Bool { get set } ``` ## Discussion Deferred Start is a feature that allows you to control, on a per-output basis, whether output objects start when or after the session is started. The session defers starting an output when its [`isDeferredStartEnabled`](/documentation/AVFoundation/AVCaptureOutput/isDeferredStartEnabled) property is set to `true`, and starts it after the session is started. When this value is `true`, [`AVCaptureSession`](/documentation/AVFoundation/AVCaptureSession) automatically runs deferred start. If only [`AVCaptureVideoPreviewLayer`](/documentation/AVFoundation/AVCaptureVideoPreviewLayer) objects have [`isDeferredStartEnabled`](/documentation/AVFoundation/AVCaptureVideoPreviewLayer/isDeferredStartEnabled) set to `false`, the session runs deferred start a short time after displaying the first frame. If there are [`AVCaptureOutput`](/documentation/AVFoundation/AVCaptureOutput) objects that have [`isDeferredStartEnabled`](/documentation/AVFoundation/AVCaptureOutput/isDeferredStartEnabled) set to `false`, then the session waits until each output that provides streaming data to your app sends its first frame. If you set this value to `false`, call [`runDeferredStartWhenNeeded()`](/documentation/AVFoundation/AVCaptureSession/runDeferredStartWhenNeeded()) to indicate when to run deferred start. By default, for apps that are linked on or after iOS 26, this value is `true`. If [`isManualDeferredStartSupported`](/documentation/AVFoundation/AVCaptureSession/isManualDeferredStartSupported) is `false`, setting this property value to false results in the session throwing an invalid argument exception. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)