---
title: AVMediaCharacteristic
framework: avfoundation
role: symbol
role_heading: Structure
path: avfoundation/avmediacharacteristic
---

# AVMediaCharacteristic

A structure that defines media data characteristics.

## Declaration

```swift
struct AVMediaCharacteristic
```

## Discussion

Discussion QuickTime Movie and MPEG-4 video files may contain tracks that provide tagged media characteristics to indicate a purpose, trait, or feature of the track’s media. For example, an audio track that mixes original program content with additional narrative descriptions of visual action may have the media characteristic public.accessibility.describes-video to distinguish it from other audio tracks stored in the same file that don’t contain additional narrative. You inspect the tagged media characteristics of a track as shown below: NSArray *userDataItems = [myAVAssetTrack metadataForFormat:AVMetadataFormatQuickTimeUserData]; NSArray *trackTaggedMediaCharacteristics = [AVMetadataItem metadataItemsFromArray: userDataItems         withKey: AVMetadataQuickTimeUserDataKeyTaggedCharacteristic         keySpace: AVMetadataKeySpaceQuickTimeUserData]; for (AVMetadataItem *metadataItem in trackTaggedMediaCharacteristics) {      NSString *thisTrackMediaCharacteristic = [metadataItem stringValue]; } You write tagged media characteristics to files of type mov and m4v by using an instance of AVAssetWriter. You indicate tagged characteristics for a track by setting metadata on its associated asset writer input as shown below: AVMutableMetadataItem *myTaggedMediaCharacteristic = [[AVMutableMetadataItem alloc] init]; [myTaggedMediaCharacteristic setKey:AVMetadataQuickTimeUserDataKeyTaggedCharacteristic]; [myTaggedMediaCharacteristic setKeySpace:AVMetadataKeySpaceQuickTimeUserData]; [myTaggedMediaCharacteristic setValue:aMeaningfulCharacteristicAsNSString]; [myMutableArrayOfMetadata addObject:myTaggedMediaCharacteristic]; [myAssetWriterInput setMetadata:myMutableArrayOfMetadata];

## Topics

### Visual

- [visual](avfoundation/avmediacharacteristic/visual.md)
- [containsAlphaChannel](avfoundation/avmediacharacteristic/containsalphachannel.md)
- [containsHDRVideo](avfoundation/avmediacharacteristic/containshdrvideo.md)
- [frameBased](avfoundation/avmediacharacteristic/framebased.md)
- [usesWideGamutColorSpace](avfoundation/avmediacharacteristic/useswidegamutcolorspace.md)
- [containsStereoMultiviewVideo](avfoundation/avmediacharacteristic/containsstereomultiviewvideo.md)
- [carriesVideoStereoMetadata](avfoundation/avmediacharacteristic/carriesvideostereometadata.md)
- [indicatesHorizontalFieldOfView](avfoundation/avmediacharacteristic/indicateshorizontalfieldofview.md)
- [indicatesNonRectilinearProjection](avfoundation/avmediacharacteristic/indicatesnonrectilinearprojection.md)

### Audible

- [audible](avfoundation/avmediacharacteristic/audible.md)
- [dubbedTranslation](avfoundation/avmediacharacteristic/dubbedtranslation.md)
- [voiceOverTranslation](avfoundation/avmediacharacteristic/voiceovertranslation.md)
- [enhancesSpeechIntelligibility](avfoundation/avmediacharacteristic/enhancesspeechintelligibility.md)
- [describesMusicAndSoundForAccessibility](avfoundation/avmediacharacteristic/describesmusicandsoundforaccessibility.md)
- [tactileMinimal](avfoundation/avmediacharacteristic/tactileminimal.md)

### Legible

- [legible](avfoundation/avmediacharacteristic/legible.md)
- [easyToRead](avfoundation/avmediacharacteristic/easytoread.md)
- [describesVideoForAccessibility](avfoundation/avmediacharacteristic/describesvideoforaccessibility.md)
- [containsOnlyForcedSubtitles](avfoundation/avmediacharacteristic/containsonlyforcedsubtitles.md)
- [languageTranslation](avfoundation/avmediacharacteristic/languagetranslation.md)
- [transcribesSpokenDialogForAccessibility](avfoundation/avmediacharacteristic/transcribesspokendialogforaccessibility.md)

### Content

- [isOriginalContent](avfoundation/avmediacharacteristic/isoriginalcontent.md)
- [isMainProgramContent](avfoundation/avmediacharacteristic/ismainprogramcontent.md)
- [isAuxiliaryContent](avfoundation/avmediacharacteristic/isauxiliarycontent.md)
- [machineGenerated](avfoundation/avmediacharacteristic/machinegenerated.md)

### Initializers

- [init(_:)](avfoundation/avmediacharacteristic/init(_:).md)
- [init(rawValue:)](avfoundation/avmediacharacteristic/init(rawvalue:).md)

## Relationships

### Conforms To

- [Equatable](swift/equatable.md)
- [Hashable](swift/hashable.md)
- [RawRepresentable](swift/rawrepresentable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Media types

- [AVMediaType](avfoundation/avmediatype.md)