# CVBuffer An abstract base class that defines how to interact with data buffers. ## Discussion A [`CVBuffer`](/documentation/CoreVideo/CVBuffer) serves as an abstract base class that defines how to interact with buffers of data. A buffer object can hold video, audio, or possibly other types of data. All the other buffer types within the Core Video framework, such as [CVImageBuffer](/documentation/CoreVideo/cvimagebuffer-q40) and [CVPixelBuffer](/documentation/CoreVideo/cvpixelbuffer-q2e), derive from [`CVBuffer`](/documentation/CoreVideo/CVBuffer). You can use the [`CVBuffer`](/documentation/CoreVideo/CVBuffer) programming interface on any Core Video buffer. ## Topics ### Working with attachments [`func CVBufferHasAttachment(CVBuffer, CFString) -> Bool`](/documentation/CoreVideo/CVBufferHasAttachment(_:_:)) Returns a Boolean value that indicates whether a Core Video buffer contains a specified attachment. [`func CVBufferCopyAttachment(CVBuffer, CFString, UnsafeMutablePointer?) -> CFTypeRef?`](/documentation/CoreVideo/CVBufferCopyAttachment(_:_:_:)) Returns a copy of an attachment from a Core Video buffer. [`func CVBufferCopyAttachments(CVBuffer, CVAttachmentMode) -> CFDictionary?`](/documentation/CoreVideo/CVBufferCopyAttachments(_:_:)) Returns a copy of all attachments from a Core Video buffer. [`func CVBufferSetAttachment(CVBuffer, CFString, CFTypeRef, CVAttachmentMode)`](/documentation/CoreVideo/CVBufferSetAttachment(_:_:_:_:)) Sets or adds an attachment to a Core Video buffer. [`func CVBufferSetAttachments(CVBuffer, CFDictionary, CVAttachmentMode)`](/documentation/CoreVideo/CVBufferSetAttachments(_:_:_:)) Sets a dictionary of attachments on a Core Video buffer. [`func CVBufferPropagateAttachments(CVBuffer, CVBuffer)`](/documentation/CoreVideo/CVBufferPropagateAttachments(_:_:)) Copies all attachments that Core Video can propagate from one buffer to another. [`func CVBufferRemoveAttachment(CVBuffer, CFString)`](/documentation/CoreVideo/CVBufferRemoveAttachment(_:_:)) Removes the attachment you specify from a Core Video buffer. [`func CVBufferRemoveAllAttachments(CVBuffer)`](/documentation/CoreVideo/CVBufferRemoveAllAttachments(_:)) Removes all attachments from a Core Video buffer. [`func CVBufferGetAttachment(CVBuffer, CFString, UnsafeMutablePointer?) -> Unmanaged?`](/documentation/CoreVideo/CVBufferGetAttachment(_:_:_:)) Retrieves a specific attachment of a Core Video buffer. [`func CVBufferGetAttachments(CVBuffer, CVAttachmentMode) -> CFDictionary?`](/documentation/CoreVideo/CVBufferGetAttachments(_:_:)) Retrieves all attachments of a Core Video buffer. ### Retaining and releasing buffers [`extern CVBufferRefCVBufferRetain(CVBufferRef buffer);`](/documentation/CoreVideo/CVBufferRetain) Retains a Core Video buffer. [`extern void CVBufferRelease(CVBufferRef buffer);`](/documentation/CoreVideo/CVBufferRelease) Releases a Core Video buffer. ### Protocols [`protocol CVBufferRepresentable`](/documentation/CoreVideo/CVBufferRepresentable) CVBufferRepresentable protocol is a sealed protocol intended to be implemented by the types in CoreVideo framework. This protocol facilitates Swift types that wrap a value of CVBuffer type. [`protocol CVAttachmentKeyDefinitions`](/documentation/CoreVideo/CVAttachmentKeyDefinitions) Marks a type as a collection of attachment keys for an attachment bearer. [`protocol CVAttachmentModePreference`](/documentation/CoreVideo/CVAttachmentModePreference) Defines preferred mode for an attachment key. [`protocol CVAttachmentValueRepresentable`](/documentation/CoreVideo/CVAttachmentValueRepresentable) Allows Swift types to be used as buffer attachment value. ### Attachment system (Swift) [`struct CVAttachmentAccess`](/documentation/CoreVideo/CVAttachmentAccess) Provides access to the attachments of a buffer. [`struct CVAttachmentContainer`](/documentation/CoreVideo/CVAttachmentContainer) Provides storage for buffer attachments independent of the buffer lifetime [`struct CVAttachmentRawValue`](/documentation/CoreVideo/CVAttachmentRawValue) A lightweight wrapper around raw attachment values. [`struct CVAttachmentKeyDefinition`](/documentation/CoreVideo/CVAttachmentKeyDefinition) Associates a raw attachment key with a value type and preferred propagation mode. [`struct CVAttachmentKeyDefinitionWithDefault`](/documentation/CoreVideo/CVAttachmentKeyDefinitionWithDefault) Associates a raw attachment key with a default value and preferred propagation mode. [`struct CVAttachmentCompositeKeyDefinition`](/documentation/CoreVideo/CVAttachmentCompositeKeyDefinition) Associates a set of raw attachment keys with a value type and preferred propagation mode. [`enum CVAttachmentModePreferenceShouldPropagate`](/documentation/CoreVideo/CVAttachmentModePreferenceShouldPropagate) Sets preferred mode for attachment to should propagate [`enum CVAttachmentModePreferenceShouldNotPropagate`](/documentation/CoreVideo/CVAttachmentModePreferenceShouldNotPropagate) Sets preferred mode for attachment to should not propagate ### Data types [`class CVBuffer`](/documentation/CoreVideo/CVBuffer) [`enum CVAttachmentMode`](/documentation/CoreVideo/CVAttachmentMode) The propagation modes of a Core Video buffer attachment. ### Constants [CVBuffer Attribute Keys](/documentation/CoreVideo/cvbuffer-attribute-keys) The attributes associated with Core Video buffers. [CVBuffer Attachment Keys](/documentation/CoreVideo/cvbuffer-attachment-keys) The attachment types for a Core Video buffer. ## See Also [Core Video Programming Guide](https://developer.apple.com/library/archive/documentation/GraphicsImaging/Conceptual/CoreVideo/CVProg_Intro/CVProg_Intro.html#//apple_ref/doc/uid/TP40001536) --- 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)