# AVAssetReader An object that reads media data from an asset. ``` class AVAssetReader ``` ## Overview Use an asset reader to read media data from instances of [`AVAsset`](/documentation/AVFoundation/AVAsset). The assets you read may represent file-based media like QuickTime movies or MPEG-4 files, or media that you compose from multiple sources using [`AVComposition`](/documentation/AVFoundation/AVComposition). ## Topics ### Creating an asset reader [`init(asset: AVAsset) throws`](/documentation/AVFoundation/AVAssetReader/init(asset:)) Creates an object to read media data from an asset. [`+ (instancetype) assetReaderWithAsset:(AVAsset *) asset error:(NSError **) outError;`](/documentation/AVFoundation/AVAssetReader/assetReaderWithAsset:error:) Returns a new object to read media data from an asset. ### Managing outputs [`func canAdd(AVAssetReaderOutput) -> Bool`](/documentation/AVFoundation/AVAssetReader/canAdd(_:)) Determines whether you can add the output to the asset reader. [`func add(AVAssetReaderOutput)`](/documentation/AVFoundation/AVAssetReader/add(_:)) Adds an output to the reader. [`var outputs: [AVAssetReaderOutput]`](/documentation/AVFoundation/AVAssetReader/outputs) The outputs from which you read media data. ### Accessing output providers [`func outputProvider(for: AVAssetReaderOutput) -> sending AVAssetReaderOutput.Provider>`](/documentation/AVFoundation/AVAssetReader/outputProvider(for:)) Attaches the output to the reader and returns an output provider for reading sample buffers. [`func outputProviderWithRandomAccess(for: AVAssetReaderOutput) -> sending (AVAssetReaderOutput.Provider>, AVAssetReaderOutput.RandomAccessController)`](/documentation/AVFoundation/AVAssetReader/outputProviderWithRandomAccess(for:)) Attaches the output to the reader and returns a tuple with an output provider for reading sample buffers, and an associated random access controller. [`func outputCaptionProvider(for: AVAssetReaderTrackOutput, validationDelegate: (any AVAssetReaderCaptionValidationHandling)?) -> sending AVAssetReaderOutput.Provider`](/documentation/AVFoundation/AVAssetReader/outputCaptionProvider(for:validationDelegate:)) Attaches the output to the reader and returns an output provider for reading caption groups. [`func outputCaptionProviderWithRandomAccess(for: AVAssetReaderTrackOutput, validationDelegate: (any AVAssetReaderCaptionValidationHandling)?) -> sending (AVAssetReaderOutput.Provider, AVAssetReaderOutput.RandomAccessController)`](/documentation/AVFoundation/AVAssetReader/outputCaptionProviderWithRandomAccess(for:validationDelegate:)) Attaches the output to the reader and returns a tuple with an output provider for reading caption groups, and an associated random access controller. [`func outputMetadataProvider(for: AVAssetReaderTrackOutput) -> sending AVAssetReaderOutput.Provider`](/documentation/AVFoundation/AVAssetReader/outputMetadataProvider(for:)) Attaches the output to the reader and returns an output provider for reading timed metadata groups. [`func outputMetadataProviderWithRandomAccess(for: AVAssetReaderTrackOutput) -> sending (AVAssetReaderOutput.Provider, AVAssetReaderOutput.RandomAccessController)`](/documentation/AVFoundation/AVAssetReader/outputMetadataProviderWithRandomAccess(for:)) Attaches the output to the reader and returns a tuple with an output provider for timed metadata groups buffers, and an associated random access controller. ### Configuring reading [`var timeRange: CMTimeRange`](/documentation/AVFoundation/AVAssetReader/timeRange) The time range within the asset to read. [`var status: AVAssetReader.Status`](/documentation/AVFoundation/AVAssetReader/status-swift.property) The status of reading sample buffers from the asset. [`enum Status`](/documentation/AVFoundation/AVAssetReader/Status-swift.enum) Values that represent the possible states of an asset reader. [`var error: (any Error)?`](/documentation/AVFoundation/AVAssetReader/error) An error that describes the reason for a failure. ### Controlling reading [`func start() throws`](/documentation/AVFoundation/AVAssetReader/start()) Prepares the reader to read media data from the asset. [`func startReading() -> Bool`](/documentation/AVFoundation/AVAssetReader/startReading()) Prepares the asset reader to start reading sample buffers from the asset. [`func cancelReading()`](/documentation/AVFoundation/AVAssetReader/cancelReading()) Cancels any background work and stops the reader’s outputs from reading more samples. ### Inspecting the asset [`var asset: AVAsset`](/documentation/AVFoundation/AVAssetReader/asset) The asset from which to read media data. ## Relationships ### Conforms To [`CVarArg`](/documentation/Swift/CVarArg) [`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible) [`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible) [`Equatable`](/documentation/Swift/Equatable) [`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol) [`Hashable`](/documentation/Swift/Hashable) ### Inherits From [`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class) --- 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)