# Media reading and writing Read images from video, export to alternative formats, and perform sample-level reading and writing of media data. ## Topics ### Media export [Exporting video to alternative formats](/documentation/AVFoundation/exporting-video-to-alternative-formats) Convert an existing movie file to a different format. [`AVAssetExportSession`](/documentation/AVFoundation/AVAssetExportSession) An object that exports assets in a format that you specify using an export preset. ### Planned export [`AVAssetWritingPlanner`](/documentation/AVFoundation/AVAssetWritingPlanner) AVAssetWritingPlanner orchestrates incremental writing of media files. [`AVAssetWritingPlannerProgress`](/documentation/AVFoundation/AVAssetWritingPlannerProgress) AVAssetWritingPlannerProgress tracks the progress of incremental writing for each track in an AVAssetWritingPlanner session. [`AVAssetTrackPlan`](/documentation/AVFoundation/AVAssetTrackPlan) AVAssetTrackPlan holds information about a track and how it should be segmented and executed in an incremental writing session. [`AVAssetVideoTrackPlan`](/documentation/AVFoundation/AVAssetVideoTrackPlan) AVAssetVideoTrackPlan holds information about a track and how it should be segmented and executed in an incremental writing session. [`AVPlannedSegmentConfiguration`](/documentation/AVFoundation/AVPlannedSegmentConfiguration) AVPlannedSegmentConfiguration describes the requirements for a planned segment in an incremental writing session executed by the AVAssetWritingPlanner. Subclasses of this type that are used from Swift must fulfill the requirements of a Sendable type. [`AVPlannedVideoSegmentConfiguration`](/documentation/AVFoundation/AVPlannedVideoSegmentConfiguration) AVPlannedVideoSegmentConfiguration describes the requirements for a planned video segment in an incremental writing session executed by the AVAssetWritingPlanner. [`AVPlannedSegmentWritingRequest`](/documentation/AVFoundation/AVPlannedSegmentWritingRequest) AVPlannedSegmentWritingRequest encompasses a request from the AVAssetWritingPlanner to the client code to write one incremental track segment. [`AVPlannedVideoSegmentWritingRequest`](/documentation/AVFoundation/AVPlannedVideoSegmentWritingRequest) AVPlannedVideoSegmentWritingRequest encompasses a request from the AVAssetWritingPlanner to the client code to write one incremental video track segment with compression. ### Image generation [Creating images from a video asset](/documentation/AVFoundation/creating-images-from-a-video-asset) Display images for specific times within the media timeline by generating images from a video’s frames. [`AVAssetImageGenerator`](/documentation/AVFoundation/AVAssetImageGenerator) An object that generates images from a video asset. ### Media reading [Reading multiview 3D video files](/documentation/AVFoundation/reading-multiview-3d-video-files) Render single images for the left eye and right eye from a multiview High Efficiency Video Coding format file by reading individual video frames. [`AVAssetReader`](/documentation/AVFoundation/AVAssetReader) An object that reads media data from an asset. [`AVAssetReaderOutput`](/documentation/AVFoundation/AVAssetReaderOutput) An abstract class that defines the interface to read media samples from an asset reader. [`AVAssetReaderTrackOutput`](/documentation/AVFoundation/AVAssetReaderTrackOutput) An object that reads media data from a single track of an asset. [`AVAssetReaderAudioMixOutput`](/documentation/AVFoundation/AVAssetReaderAudioMixOutput) An object that reads audio samples that result from mixing audio from one or more tracks. [`AVAssetReaderVideoCompositionOutput`](/documentation/AVFoundation/AVAssetReaderVideoCompositionOutput) An object that reads composited video frames from one or more tracks of an asset. [`AVAssetReaderSampleReferenceOutput`](/documentation/AVFoundation/AVAssetReaderSampleReferenceOutput) An object that reads sample references from an asset track. [`AVAssetReaderOutputMetadataAdaptor`](/documentation/AVFoundation/AVAssetReaderOutputMetadataAdaptor) An object that creates timed metadata group objects for an asset track. ### Media writing [Converting projected video to Apple Projected Media Profile](/documentation/AVFoundation/converting-projected-video-to-apple-projected-media-profile) Convert content with equirectangular or half-equirectangular projection to APMP. [Converting side-by-side 3D video to multiview HEVC and spatial video](/documentation/AVFoundation/converting-side-by-side-3d-video-to-multiview-hevc-and-spatial-video) Create video content for visionOS by converting an existing 3D HEVC file to a multiview HEVC format, optionally adding spatial metadata to create a spatial video. [Adding a display mask rectangle metadata track to a movie file](/documentation/AVFoundation/adding-a-display-mask-rectangle-metadata-track-to-a-movie-file) Show a specific area of a video by using timed display mask rectangle metadata. [Writing fragmented MPEG-4 files for HTTP Live Streaming](/documentation/AVFoundation/writing-fragmented-mpeg-4-files-for-http-live-streaming) Create an HTTP Live Streaming presentation by turning a movie file into a sequence of fragmented MPEG-4 files. [Tagging media with video color information](/documentation/AVFoundation/tagging-media-with-video-color-information) Inspect and set video color space information when writing and transcoding media. [Evaluating an app’s video color](/documentation/AVFoundation/evaluating-an-app-s-video-color) Check color reproduction for a video in your app by using test patterns, video test equipment, and light-measurement instruments. [`AVOutputSettingsAssistant`](/documentation/AVFoundation/AVOutputSettingsAssistant) An object that builds audio and video output settings dictionaries. [`AVAssetWriter`](/documentation/AVFoundation/AVAssetWriter) An object that writes media data to a container file. [`AVAssetWriterInput`](/documentation/AVFoundation/AVAssetWriterInput) An object that appends media samples to a track in an asset writer’s output file. [`AVAssetWriterInputPixelBufferAdaptor`](/documentation/AVFoundation/AVAssetWriterInputPixelBufferAdaptor) An object that appends video samples to an asset writer input. [`AVAssetWriterInputTaggedPixelBufferGroupAdaptor`](/documentation/AVFoundation/AVAssetWriterInputTaggedPixelBufferGroupAdaptor) An object that appends tagged buffer groups to an asset writer input. [`AVAssetWriterInputMetadataAdaptor`](/documentation/AVFoundation/AVAssetWriterInputMetadataAdaptor) An object that appends timed metadata groups to an asset writer input. [`AVAssetWriterInputGroup`](/documentation/AVFoundation/AVAssetWriterInputGroup) A group of inputs with tracks that are mutually exclusive to each other for playback or processing. ### Captions [Caption authoring](/documentation/AVFoundation/caption-authoring) Create captions and subtitles in industry-standard formats. --- 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)