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# MEFormatReader

A protocol that defines the requirements for a format reader, which represents a single media asset.

```
protocol MEFormatReader : NSObjectProtocol
```

## Overview

This protocol provides an interface for the Media Toolbox to interact with extension plug-in format readers, which provide information about media assets. `MEFormatReader` objects are always instantiated by the Media Toolbox.

> Note:
> Developers who wish to build MediaExtension format readers using this API need to include a <doc://com.apple.mediaextension/documentation/MediaExtension/format-reader-entitlement>, provisioning profile, and specialized dictionary in their Info.plist file when building their extensions.
> 
> For more information, see [Entitlements](https://developer.apple.com/documentation/bundleresources/entitlements), [Create a development provisioning profile](https://developer.apple.com/help/account/manage-provisioning-profiles/create-a-development-provisioning-profile), and <doc://com.apple.mediaextension/documentation/MediaExtension/format-reader-property-list-dictionaries>.

To create an `MEFormatReader` object, Media Toolbox first creates a primary [`MEByteSource`](/documentation/MediaExtension/MEByteSource) object from a source media asset. It then creates an [`MEFormatReaderExtension`](/documentation/MediaExtension/MEFormatReaderExtension) object and calls its [`formatReader(with:options:)`](/documentation/MediaExtension/MEFormatReaderExtension/formatReader(with:options:)) method.

Once a user installs and runs the host app, embedded MediaExtension format reader extensions become available to any app on the user’s system that opts in to using them by calling <doc://com.apple.documentation/documentation/MediaToolbox/MTRegisterProfessionalVideoWorkflowFormatReaders()>.

> Important:
> `MEFormatReader` objects run in a sandboxed process with restricted access to the filesystem, network, and other kernel resources.

## Topics

### Reading and parsing media assets

[`-  loadFileInfoWithCompletionHandler:`](/documentation/MediaExtension/MEFormatReader/loadFileInfo(completionHandler:))

Loads the file info object with the properties of the media asset.

[`-  loadMetadataWithCompletionHandler:`](/documentation/MediaExtension/MEFormatReader/loadMetadata(completionHandler:))

Loads the array of metadata items from the media asset.

[`-  loadTrackReadersWithCompletionHandler:`](/documentation/MediaExtension/MEFormatReader/loadTrackReaders(completionHandler:))

Loads the array of track readers that represent the tracks in the media asset.

[`-  parseAdditionalFragmentsWithCompletionHandler:`](/documentation/MediaExtension/MEFormatReader/parseAdditionalFragments(completionHandler:))

Incorporates additional fragments that the file received after the last time the format reader parsed it.

[`MEFormatReaderParseAdditionalFragmentsStatus`](/documentation/MediaExtension/MEFormatReaderParseAdditionalFragmentsStatus)

Informational status flags that the format reader returns after parsing additional fragments.

### Extension requirements

[Format reader property list dictionaries](/documentation/MediaExtension/format-reader-property-list-dictionaries)

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

[Format reader entitlement](/documentation/MediaExtension/format-reader-entitlement)

Include an entitlement to indicate your extension is a MediaExtension format reader.

## Relationships

### Inherits From

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

---

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