---
title: Format reader property list dictionaries
framework: MediaExtension
role: collectionGroup
role_heading: API Collection
path: mediaextension/format-reader-property-list-dictionaries
---

# Format reader property list dictionaries

Include property list dictionaries to describe a format reader and register the formats it supports.

## Overview

Overview An ExtensionKit format reader needs to include one required dictionary and can also include an optional dictionary in its Info.plist file: EXAppExtensionAttributes: A required dictionary that describes the format reader and contains the following keys and values: kMEFormatReaderClassImplementationIDKey: The identifier for the format reader. Format similarly to the bundle identifier. EXExtensionPointIdentifier: The extension point name for format readers. Set to the value for kMEFormatReaderExtensionPointName. EXPrincipalClass: The name of the format reader factory class that conforms to the MEFormatReaderExtension protocol. kMEFormatReaderFileNameExtensionArrayKey: An array of strings that specify the file name extensions that the format reader supports. kMEFormatReaderUTTypeArrayKey: A key to the array of Uniform Type Identifiers that the format reader supports. kMEFormatReaderObjectNameKey: A user-readable string that describes the format reader. UTExportedTypeDeclarations: An optional dictionary that registers the formats from the kMEFormatReaderUTTypeArrayKey array that the format reader supports, so the system can recognize those media files and open them in the appropriate app. It contains the following keys and values: UTTypeDescription: A user-readable string that specifies the media kind, which Finder displays. UTTypeConformsTo: An array of UTType identifiers, with the first entry set to com.apple.mediaextension-content. This type also conforms to higher level abstract types such as public.movie and public.audiovisual-content. This array can include additional types as needed. UTTypeIdentifier: This value needs to match the value for kMEFormatReaderUTTypeArrayKey in the EXAppExtensionAttributes dictionary. UTTypeTagSpecification, public.filename-extension key: This value needs to match the value for kMEFormatReaderFileNameExtensionArrayKey in the EXAppExtensionAttributes dictionary. public.mime-type: This is an optional key to a MIME type that corresponds to the format. For general information on how to make a UTExportedTypeDeclarations dictionary, see UTExportedTypeDeclarations.

## Topics

### Property list keys

- [kMEFormatReaderClassImplementationIDKey](mediaextension/kmeformatreaderclassimplementationidkey.md)
- [kMEFormatReaderExtensionPointName](mediaextension/kmeformatreaderextensionpointname.md)
- [kMEFormatReaderFileNameExtensionArrayKey](mediaextension/kmeformatreaderfilenameextensionarraykey.md)
- [kMEFormatReaderUTTypeArrayKey](mediaextension/kmeformatreaderuttypearraykey.md)
- [kMEFormatReaderObjectNameKey](mediaextension/kmeformatreaderobjectnamekey.md)

## See Also

### Format readers

- [Supporting custom media formats and decoders](mediaextension/supporting-custom-media-formats-and-decoders.md)
- [MEFormatReader](mediaextension/meformatreader.md)
- [MEFormatReaderExtension](mediaextension/meformatreaderextension.md)
- [MEFormatReaderInstantiationOptions](mediaextension/meformatreaderinstantiationoptions.md)
- [MEFileInfo](mediaextension/mefileinfo.md)
- [Format reader entitlement](mediaextension/format-reader-entitlement.md)