---
title: Image Buffer Transfer Function Constants
framework: corevideo
role: collectionGroup
role_heading: API Collection
path: corevideo/image-buffer-transfer-function-constants
---

# Image Buffer Transfer Function Constants

Constants that indicate the transfer function for the image buffer.

## Overview

Overview Use the kCVImageBufferTransferFunctionKey key to attach one of these values to the image buffer. The transfer function describes the tonality of an image for use in color matching operations, along with a color primaries gamut (See Image Buffer Color Primaries Constants for more information.). Most apps should specify the kCVImageBufferTransferFunction_ITU_R_709_2 transfer function.

## Topics

### Constants

- [kCVImageBufferTransferFunction_ITU_R_709_2](corevideo/kcvimagebuffertransferfunction_itu_r_709_2.md)
- [kCVImageBufferTransferFunction_SMPTE_240M_1995](corevideo/kcvimagebuffertransferfunction_smpte_240m_1995.md)
- [kCVImageBufferTransferFunction_UseGamma](corevideo/kcvimagebuffertransferfunction_usegamma.md)
- [kCVImageBufferTransferFunction_sRGB](corevideo/kcvimagebuffertransferfunction_srgb.md)
- [kCVImageBufferTransferFunction_ITU_R_2020](corevideo/kcvimagebuffertransferfunction_itu_r_2020.md)
- [kCVImageBufferTransferFunction_SMPTE_ST_428_1](corevideo/kcvimagebuffertransferfunction_smpte_st_428_1.md)
- [kCVImageBufferTransferFunction_ITU_R_2100_HLG](corevideo/kcvimagebuffertransferfunction_itu_r_2100_hlg.md)
- [kCVImageBufferTransferFunction_SMPTE_ST_2084_PQ](corevideo/kcvimagebuffertransferfunction_smpte_st_2084_pq.md)
- [kCVImageBufferLogTransferFunction_AppleLog2](corevideo/kcvimagebufferlogtransferfunction_applelog2.md)

## See Also

### Constants

- [Image Buffer Attachment Keys](corevideo/image-buffer-attachment-keys.md)
- [Image Buffer Clean Aperture Keys](corevideo/image-buffer-clean-aperture-keys.md)
- [Image Buffer Pixel Aspect Ratio Keys](corevideo/image-buffer-pixel-aspect-ratio-keys.md)
- [Image Buffer Display Dimensions Keys](corevideo/image-buffer-display-dimensions-keys.md)
- [Image Buffer Field Detail Constants](corevideo/image-buffer-field-detail-constants.md)
- [Image Buffer YCbCr Matrix Constants](corevideo/image-buffer-ycbcr-matrix-constants.md)
- [Image Buffer Color Primaries Constants](corevideo/image-buffer-color-primaries-constants.md)
- [Image Buffer Chroma Location Constants](corevideo/image-buffer-chroma-location-constants.md)
- [Image Buffer Chroma Subsampling Constants](corevideo/image-buffer-chroma-subsampling-constants.md)
- [Image Buffer Display Mask Rectangle Keys](corevideo/image-buffer-display-mask-rectangle-keys.md)
- [kCVImageBufferDisplayMaskRectangleKey](corevideo/kcvimagebufferdisplaymaskrectanglekey.md)
- [kCVImageBufferDisplayMaskRectangleStereoLeftKey](corevideo/kcvimagebufferdisplaymaskrectanglestereoleftkey.md)
- [kCVImageBufferDisplayMaskRectangleStereoRightKey](corevideo/kcvimagebufferdisplaymaskrectanglestereorightkey.md)