Type	Topic	Plugin	Version	macOS	Windows	Linux	iOS	Targets
class	AVFoundation	MBS AVFoundation Plugin	14.4	✅ Yes	❌ No	❌ No	✅ Yes	All

AVAssetReaderSampleReferenceOutput is a concrete subclass of AVAssetReaderOutput that defines an interface for reading sample references from a single AVAssetTrack of an AVAssetReader's AVAsset.

Clients can extract information about the location (file URL and offset) of samples in a track by adding an instance of AVAssetReaderSampleReferenceOutput to an AVAssetReader using the AVAssetReader.addOutput method. No actual sample data can be extracted using this class. The location of the sample data is described by the kCMSampleBufferAttachmentKey_SampleReferenceURL and kCMSampleBufferAttachmentKey_SampleReferenceByteOffset attachments on the extracted sample buffers. More information about sample buffers describing sample references can be found in the CMSampleBuffer documentation.

Sample buffers extracted using this class can also be appended to an AVAssetWriterInput to create movie tracks that are not self-contained and reference data in the original file instead. Currently, only instances of AVAssetWriter configured to write files of type AVFileTypeQuickTimeMovie can be used to write tracks that are not self-contained.

Since no sample data is ever returned by instances of AVAssetReaderSampleReferenceOutput, the value of the alwaysCopiesSampleData property is ignored.

Available on Mac OS X 10.10 or newer.
Subclass of the AVAssetReaderOutputMBS class.