# CMIOExtensionDevice An object that represents a physical or virtual device. ``` class CMIOExtensionDevice ``` ## Overview A device provides one or more streams of media data to a [`CMIOExtensionProvider`](/documentation/CoreMediaIO/CMIOExtensionProvider). ## Topics ### Creating a Device [`+ (instancetype) deviceWithLocalizedName:(NSString *) localizedName deviceID:(NSUUID *) deviceID source:(id) source;`](/documentation/CoreMediaIO/CMIOExtensionDevice/deviceWithLocalizedName:deviceID:source:) Returns a new extension device. [`+ (instancetype) deviceWithLocalizedName:(NSString *) localizedName deviceID:(NSUUID *) deviceID legacyDeviceID:(NSString *) legacyDeviceID source:(id) source;`](/documentation/CoreMediaIO/CMIOExtensionDevice/deviceWithLocalizedName:deviceID:legacyDeviceID:source:) Returns a new extension device with an optional legacy device identifier. [`convenience init(localizedName: String, deviceID: UUID, source: any CMIOExtensionDeviceSource)`](/documentation/CoreMediaIO/CMIOExtensionDevice/init(localizedName:deviceID:source:)) Creates an extension device. [`init(localizedName: String, deviceID: UUID, legacyDeviceID: String?, source: any CMIOExtensionDeviceSource)`](/documentation/CoreMediaIO/CMIOExtensionDevice/init(localizedName:deviceID:legacyDeviceID:source:)) Creates an extension device with an optional legacy device identifier. ### Identifying a Device [`var localizedName: String`](/documentation/CoreMediaIO/CMIOExtensionDevice/localizedName) A localized name for a device. [`var deviceID: UUID`](/documentation/CoreMediaIO/CMIOExtensionDevice/deviceID) A universally unique device identifier value. [`var legacyDeviceID: String`](/documentation/CoreMediaIO/CMIOExtensionDevice/legacyDeviceID) A legacy device identifier. ### Managing Streams [`var streams: [CMIOExtensionStream]`](/documentation/CoreMediaIO/CMIOExtensionDevice/streams) An array of media streams attached to this device. [`func addStream(CMIOExtensionStream) throws`](/documentation/CoreMediaIO/CMIOExtensionDevice/addStream(_:)) Adds a stream to a device. [`func removeStream(CMIOExtensionStream) throws`](/documentation/CoreMediaIO/CMIOExtensionDevice/removeStream(_:)) Removes a stream from the device. ### Accessing the Device Source [`var source: (any CMIOExtensionDeviceSource)?`](/documentation/CoreMediaIO/CMIOExtensionDevice/source) A source object for a device. ### Posting Property Changes [`func notifyPropertiesChanged([CMIOExtensionProperty : CMIOExtensionPropertyState])`](/documentation/CoreMediaIO/CMIOExtensionDevice/notifyPropertiesChanged(_:)) Notifies clients of property changes. ## Relationships ### Inherits From [`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class) ### Conforms To [`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible) [`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol) [`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible) [`CVarArg`](/documentation/Swift/CVarArg) [`Hashable`](/documentation/Swift/Hashable) [`Equatable`](/documentation/Swift/Equatable) --- 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)