---
title: Core Media
framework: Core Media
role: collection
role_heading: Framework
platforms: [iOS 4.0+, Mac Catalyst 13.1+, macOS 10.7+, tvOS 9.0+, visionOS 1.0+, watchOS 6.0+]
path: coremedia
---

# Core Media

Represent time-based audio-visual assets with essential data types.

## Overview

Overview The Core Media framework defines the media pipeline used by AVFoundation and other high-level media frameworks found on Apple platforms. Use Core Media’s low-level data types and interfaces to efficiently process media samples and manage queues of media data.

## Topics

### Sample Processing

- [CMSampleBuffer](coremedia/cmsamplebuffer-api.md)
- [CMBlockBuffer](coremedia/cmblockbuffer-api.md)
- [CMTaggedBufferGroup](coremedia/cmtaggedbuffergroup.md)
- [CMFormatDescription](coremedia/cmformatdescription-api.md)
- [CMAttachment](coremedia/cmattachment-api.md)
- [CMTaggedBuffer](coremedia/cmtaggedbuffer.md)
- [CMMutableDataBlockBuffer](coremedia/cmmutabledatablockbuffer.md)
- [CMReadOnlyDataBlockBuffer](coremedia/cmreadonlydatablockbuffer.md)
- [CMReadySampleBuffer](coremedia/cmreadysamplebuffer.md)
- [CMSampleDataReference](coremedia/cmsampledatareference.md)
- [CMTaggedDynamicBuffer](coremedia/cmtaggeddynamicbuffer.md)

### Time Representation

- [CMTime](coremedia/cmtime-api.md)
- [CMTimeRange](coremedia/cmtimerange-api.md)
- [CMTimeMapping](coremedia/cmtimemapping-api.md)

### Media Synchronization

- [CMClock](coremedia/cmclock-api.md)
- [CMAudioClock](coremedia/cmaudioclock-api.md)
- [CMTimebase](coremedia/cmtimebase-api.md)

### Text Markup

- [CMTextMarkup](coremedia/cmtextmarkup.md)

### Metadata

- [CMMetadata](coremedia/cmmetadata.md)
- [CMTag](coremedia/cmtag-api.md)
- [CMTag](coremedia/cmtag-swift.class.md)
- [CMTypedTag](coremedia/cmtypedtag.md)
- [CMTagCollection](coremedia/cmtagcollection.md)
- [CMProjectionType](coremedia/cmprojectiontype.md)
- [CMStereoViewComponents](coremedia/cmstereoviewcomponents.md)
- [CMStereoViewInterpretationOptions](coremedia/cmstereoviewinterpretationoptions.md)
- [CMPackingType](coremedia/cmpackingtype.md)

### Queues

- [CMSimpleQueue](coremedia/cmsimplequeue-api.md)
- [CMBufferQueue](coremedia/cmbufferqueue-api.md)
- [CMMemoryPool](coremedia/cmmemorypool-api.md)

### Reference

- [Core Media Constants](coremedia/core-media-constants.md)
- [Core Media Functions](coremedia/core-media-functions.md)
- [Core Media Type Aliases](coremedia/core-media-type-aliases.md)

### Structures

- [CMCameraIntrinsicMatrix](coremedia/cmcameraintrinsicmatrix.md)
- [CMCustomNotificationInfo](coremedia/cmcustomnotificationinfo.md)

### Variables

- [COREMEDIA_SUPPORTS_GENLOCK_CLOCK](coremedia/coremedia_supports_genlock_clock.md)
- [kCMClockError_PreferredStartTimeNotAvailable](coremedia/kcmclockerror_preferredstarttimenotavailable.md)
- [kCMFormatDescriptionLogTransferFunction_AppleLog2](coremedia/kcmformatdescriptionlogtransferfunction_applelog2.md)
- [kCMGenlockClockNotificationPayload_AnyDisplayIsSynchronizedToLockedGenlockSignal](coremedia/kcmgenlockclocknotificationpayload_anydisplayissynchronizedtolockedgenlocksignal.md)
- [kCMGenlockClockNotification_DisplayGenlockModeChanged](coremedia/kcmgenlockclocknotification_displaygenlockmodechanged.md)
- [kCMMetadataBaseDataType_ISOLatin1](coremedia/kcmmetadatabasedatatype_isolatin1.md)
- [kCMMetadataBaseDataType_MacRoman](coremedia/kcmmetadatabasedatatype_macroman.md)
- [kCMMetadataDataType_QuickTimeMetadataSMPTE2094_50](coremedia/kcmmetadatadatatype_quicktimemetadatasmpte2094_50.md)
- [kCMMetadataFormatDescriptionKey_HumanReadableString](coremedia/kcmmetadataformatdescriptionkey_humanreadablestring.md)
- [kCMMetadataFormatDescriptionMetadataSpecificationKey_HumanReadableString](coremedia/kcmmetadataformatdescriptionmetadataspecificationkey_humanreadablestring.md)
- [kCMMetadataIdentifier_ITUT_T35MetadataSMPTE2094_50](coremedia/kcmmetadataidentifier_itut_t35metadatasmpte2094_50.md)

### Type Aliases

- [CMAttachmentAccess](coremedia/cmattachmentaccess.md)
- [CMAttachmentContainer](coremedia/cmattachmentcontainer.md)
- [CMAttachmentKeyDefinitions](coremedia/cmattachmentkeydefinitions.md)
- [CMAttachmentPropagationMode](coremedia/cmattachmentpropagationmode.md)
- [CMAttachmentRawValue](coremedia/cmattachmentrawvalue.md)
- [CMAttachmentValueRepresentable](coremedia/cmattachmentvaluerepresentable.md)

### Enumerations

- [CMBlockBufferAttachmentKeyDefinitions](coremedia/cmblockbufferattachmentkeydefinitions.md)
- [CMDroppedFrameReason](coremedia/cmdroppedframereason.md)
- [CMSampleBufferAttachmentKeyDefinitions](coremedia/cmsamplebufferattachmentkeydefinitions.md)
- [CMStillImageLensStabilization](coremedia/cmstillimagelensstabilization.md)