Returns an array of the keys that are used both as CMVideo extensions and CVImage attachments and attributes.
SDKs
- iOS 4.0+
- macOS 10.7+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 6.0+
Framework
- Core Media
Declaration
CFArrayDiscussion
When specifying a CMFormat for a CMSample, the format description must be consistent with formatting information attached to the CVImage. The width, height, and codecType must match (for CVPixel the codec type is given by CVPixel(pixelBuffer); for other CVImage, the codecType must be 0). The format description extensions must match the image buffer attachments for all the keys in the list returned by this function (if absent in either they must be absent in both). Currently, the list is:
kCMFormatDescriptionExtension_CleanAperture
kCMFormatDescriptionExtension_FieldCount
kCMFormatDescriptionExtension_FieldDetail
kCMFormatDescriptionExtension_PixelAspectRatio
kCMFormatDescriptionExtension_ColorPrimaries
kCMFormatDescriptionExtension_TransferFunction
kCMFormatDescriptionExtension_GammaLevel
kCMFormatDescriptionExtension_YCbCrMatrix
kCMFormatDescriptionExtension_ICCProfile
kCMFormatDescriptionExtension_ChromaLocationTopField
kCMFormatDescriptionExtension_ChromaLocationBottomField