---
title: Compression Properties
framework: videotoolbox
role: collectionGroup
role_heading: API Collection
path: videotoolbox/compression-properties
---

# Compression Properties

Properties that you use to configure a compression session.

## Overview

Overview note: Video encoders may not support all compression property keys.

## Topics

### Bitstream Configuration

- [kVTCompressionPropertyKey_Depth](videotoolbox/kvtcompressionpropertykey_depth.md)
- [kVTCompressionPropertyKey_H264EntropyMode](videotoolbox/kvtcompressionpropertykey_h264entropymode.md)
- [kVTCompressionPropertyKey_HDRMetadataInsertionMode](videotoolbox/kvtcompressionpropertykey_hdrmetadatainsertionmode.md)
- [kVTCompressionPropertyKey_OutputBitDepth](videotoolbox/kvtcompressionpropertykey_outputbitdepth.md)
- [kVTCompressionPropertyKey_PreserveAlphaChannel](videotoolbox/kvtcompressionpropertykey_preservealphachannel.md)
- [kVTCompressionPropertyKey_PreserveDynamicHDRMetadata](videotoolbox/kvtcompressionpropertykey_preservedynamichdrmetadata.md)
- [kVTCompressionPropertyKey_ProfileLevel](videotoolbox/kvtcompressionpropertykey_profilelevel.md)

### Buffers

- [kVTCompressionPropertyKey_NumberOfPendingFrames](videotoolbox/kvtcompressionpropertykey_numberofpendingframes.md)
- [kVTCompressionPropertyKey_PixelBufferPoolIsShared](videotoolbox/kvtcompressionpropertykey_pixelbufferpoolisshared.md)
- [kVTCompressionPropertyKey_VideoEncoderPixelBufferAttributes](videotoolbox/kvtcompressionpropertykey_videoencoderpixelbufferattributes.md)

### Camera Calibration

- [kVTCompressionPropertyKey_CameraCalibrationDataLensCollection](videotoolbox/kvtcompressionpropertykey_cameracalibrationdatalenscollection.md)
- [kVTCompressionPropertyCameraCalibrationKey_ExtrinsicOrientationQuaternion](videotoolbox/kvtcompressionpropertycameracalibrationkey_extrinsicorientationquaternion.md)
- [kVTCompressionPropertyCameraCalibrationKey_ExtrinsicOriginSource](videotoolbox/kvtcompressionpropertycameracalibrationkey_extrinsicoriginsource.md)
- [kVTCompressionPropertyCameraCalibrationKey_IntrinsicMatrix](videotoolbox/kvtcompressionpropertycameracalibrationkey_intrinsicmatrix.md)
- [kVTCompressionPropertyCameraCalibrationKey_IntrinsicMatrixProjectionOffset](videotoolbox/kvtcompressionpropertycameracalibrationkey_intrinsicmatrixprojectionoffset.md)
- [kVTCompressionPropertyCameraCalibrationKey_IntrinsicMatrixReferenceDimensions](videotoolbox/kvtcompressionpropertycameracalibrationkey_intrinsicmatrixreferencedimensions.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensAlgorithmKind](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensalgorithmkind.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensDistortions](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensdistortions.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensDomain](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensdomain.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensFrameAdjustmentsPolynomialX](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensframeadjustmentspolynomialx.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensFrameAdjustmentsPolynomialY](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensframeadjustmentspolynomialy.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensIdentifier](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensidentifier.md)
- [kVTCompressionPropertyCameraCalibrationKey_LensRole](videotoolbox/kvtcompressionpropertycameracalibrationkey_lensrole.md)
- [kVTCompressionPropertyCameraCalibrationKey_RadialAngleLimit](videotoolbox/kvtcompressionpropertycameracalibrationkey_radialanglelimit.md)

### Clean Aperture and Pixel Aspect Ratio

- [kVTCompressionPropertyKey_AspectRatio16x9](videotoolbox/kvtcompressionpropertykey_aspectratio16x9.md)
- [kVTCompressionPropertyKey_CleanAperture](videotoolbox/kvtcompressionpropertykey_cleanaperture.md)
- [kVTCompressionPropertyKey_FieldCount](videotoolbox/kvtcompressionpropertykey_fieldcount.md)
- [kVTCompressionPropertyKey_FieldDetail](videotoolbox/kvtcompressionpropertykey_fielddetail.md)
- [kVTCompressionPropertyKey_PixelAspectRatio](videotoolbox/kvtcompressionpropertykey_pixelaspectratio.md)
- [kVTCompressionPropertyKey_ProgressiveScan](videotoolbox/kvtcompressionpropertykey_progressivescan.md)

### Color

- [kVTCompressionPropertyKey_AlphaChannelMode](videotoolbox/kvtcompressionpropertykey_alphachannelmode.md)
- [kVTCompressionPropertyKey_ColorPrimaries](videotoolbox/kvtcompressionpropertykey_colorprimaries.md)
- [kVTCompressionPropertyKey_ContentLightLevelInfo](videotoolbox/kvtcompressionpropertykey_contentlightlevelinfo.md)
- [kVTCompressionPropertyKey_GammaLevel](videotoolbox/kvtcompressionpropertykey_gammalevel.md)
- [kVTCompressionPropertyKey_ICCProfile](videotoolbox/kvtcompressionpropertykey_iccprofile.md)
- [kVTCompressionPropertyKey_MasteringDisplayColorVolume](videotoolbox/kvtcompressionpropertykey_masteringdisplaycolorvolume.md)
- [kVTCompressionPropertyKey_TransferFunction](videotoolbox/kvtcompressionpropertykey_transferfunction.md)
- [kVTCompressionPropertyKey_YCbCrMatrix](videotoolbox/kvtcompressionpropertykey_ycbcrmatrix.md)

### Compression Presets

- [kVTCompressionPreset_Balanced](videotoolbox/kvtcompressionpreset_balanced.md)
- [kVTCompressionPreset_HighQuality](videotoolbox/kvtcompressionpreset_highquality.md)
- [kVTCompressionPreset_HighSpeed](videotoolbox/kvtcompressionpreset_highspeed.md)
- [kVTCompressionPreset_VideoConferencing](videotoolbox/kvtcompressionpreset_videoconferencing.md)
- [kVTCompressionPropertyKey_SupportedPresetDictionaries](videotoolbox/kvtcompressionpropertykey_supportedpresetdictionaries.md)

### Encoder Selection

- [kVTCompressionPropertyKey_EncoderID](videotoolbox/kvtcompressionpropertykey_encoderid.md)
- [kVTVideoEncoderSpecification_EnableHardwareAcceleratedVideoEncoder](videotoolbox/kvtvideoencoderspecification_enablehardwareacceleratedvideoencoder.md)
- [kVTVideoEncoderSpecification_EnableLowLatencyRateControl](videotoolbox/kvtvideoencoderspecification_enablelowlatencyratecontrol.md)
- [kVTVideoEncoderSpecification_EncoderID](videotoolbox/kvtvideoencoderspecification_encoderid.md)
- [kVTVideoEncoderSpecification_PreferredEncoderGPURegistryID](videotoolbox/kvtvideoencoderspecification_preferredencodergpuregistryid.md)
- [kVTVideoEncoderSpecification_RequiredEncoderGPURegistryID](videotoolbox/kvtvideoencoderspecification_requiredencodergpuregistryid.md)
- [kVTVideoEncoderSpecification_RequireHardwareAcceleratedVideoEncoder](videotoolbox/kvtvideoencoderspecification_requirehardwareacceleratedvideoencoder.md)

### Encoding Hints

- [kVTCompressionPropertyKey_ExpectedDuration](videotoolbox/kvtcompressionpropertykey_expectedduration.md)
- [kVTCompressionPropertyKey_ExpectedFrameRate](videotoolbox/kvtcompressionpropertykey_expectedframerate.md)
- [kVTCompressionPropertyKey_MaximumRealTimeFrameRate](videotoolbox/kvtcompressionpropertykey_maximumrealtimeframerate.md)
- [kVTCompressionPropertyKey_PrioritizeEncodingSpeedOverQuality](videotoolbox/kvtcompressionpropertykey_prioritizeencodingspeedoverquality.md)
- [kVTCompressionPropertyKey_ReferenceBufferCount](videotoolbox/kvtcompressionpropertykey_referencebuffercount.md)
- [kVTCompressionPropertyKey_SourceFrameCount](videotoolbox/kvtcompressionpropertykey_sourceframecount.md)
- [kVTCompressionPropertyKey_SuggestedLookAheadFrameCount](videotoolbox/kvtcompressionpropertykey_suggestedlookaheadframecount.md)

### Frame Dependency

- [kVTCompressionPropertyKey_AllowFrameReordering](videotoolbox/kvtcompressionpropertykey_allowframereordering.md)
- [kVTCompressionPropertyKey_AllowOpenGOP](videotoolbox/kvtcompressionpropertykey_allowopengop.md)
- [kVTCompressionPropertyKey_AllowTemporalCompression](videotoolbox/kvtcompressionpropertykey_allowtemporalcompression.md)
- [kVTCompressionPropertyKey_MaxKeyFrameInterval](videotoolbox/kvtcompressionpropertykey_maxkeyframeinterval.md)
- [kVTCompressionPropertyKey_MaxKeyFrameIntervalDuration](videotoolbox/kvtcompressionpropertykey_maxkeyframeintervalduration.md)

### Hardware Acceleration

- [kVTCompressionPropertyKey_UsingGPURegistryID](videotoolbox/kvtcompressionpropertykey_usinggpuregistryid.md)
- [kVTCompressionPropertyKey_UsingHardwareAcceleratedVideoEncoder](videotoolbox/kvtcompressionpropertykey_usinghardwareacceleratedvideoencoder.md)

### Long-Term Reference

- [kVTCompressionPropertyKey_EnableLTR](videotoolbox/kvtcompressionpropertykey_enableltr.md)
- [kVTEncodeFrameOptionKey_AcknowledgedLTRTokens](videotoolbox/kvtencodeframeoptionkey_acknowledgedltrtokens.md)
- [kVTEncodeFrameOptionKey_ForceLTRRefresh](videotoolbox/kvtencodeframeoptionkey_forceltrrefresh.md)
- [kVTSampleAttachmentKey_RequireLTRAcknowledgementToken](videotoolbox/kvtsampleattachmentkey_requireltracknowledgementtoken.md)

### Multipass Storage

- [kVTCompressionPropertyKey_MultiPassStorage](videotoolbox/kvtcompressionpropertykey_multipassstorage.md)

### Multiview Compression

- [kVTCompressionPropertyKey_MVHEVCLeftAndRightViewIDs](videotoolbox/kvtcompressionpropertykey_mvhevcleftandrightviewids.md)
- [kVTCompressionPropertyKey_MVHEVCVideoLayerIDs](videotoolbox/kvtcompressionpropertykey_mvhevcvideolayerids.md)
- [kVTCompressionPropertyKey_MVHEVCViewIDs](videotoolbox/kvtcompressionpropertykey_mvhevcviewids.md)

### Parallelization

- [kVTCompressionPropertyKey_RecommendedParallelizationLimit](videotoolbox/kvtcompressionpropertykey_recommendedparallelizationlimit.md)
- [kVTCompressionPropertyKey_RecommendedParallelizedSubdivisionMinimumDuration](videotoolbox/kvtcompressionpropertykey_recommendedparallelizedsubdivisionminimumduration.md)
- [kVTCompressionPropertyKey_RecommendedParallelizedSubdivisionMinimumFrameCount](videotoolbox/kvtcompressionpropertykey_recommendedparallelizedsubdivisionminimumframecount.md)

### Per-Frame Configuration

- [kVTEncodeFrameOptionKey_BaseFrameQP](videotoolbox/kvtencodeframeoptionkey_baseframeqp.md)
- [kVTEncodeFrameOptionKey_ForceKeyFrame](videotoolbox/kvtencodeframeoptionkey_forcekeyframe.md)

### Precompression Processing

- [kVTCompressionPropertyKey_PixelTransferProperties](videotoolbox/kvtcompressionpropertykey_pixeltransferproperties.md)

### Quality Metrics

- [kVTCompressionPropertyKey_CalculateMeanSquaredError](videotoolbox/kvtcompressionpropertykey_calculatemeansquarederror.md)
- [kVTSampleAttachmentKey_QualityMetrics](videotoolbox/kvtsampleattachmentkey_qualitymetrics.md)
- [kVTSampleAttachmentQualityMetricsKey_ChromaBlueMeanSquaredError](videotoolbox/kvtsampleattachmentqualitymetricskey_chromabluemeansquarederror.md)
- [kVTSampleAttachmentQualityMetricsKey_ChromaRedMeanSquaredError](videotoolbox/kvtsampleattachmentqualitymetricskey_chromaredmeansquarederror.md)
- [kVTSampleAttachmentQualityMetricsKey_LumaMeanSquaredError](videotoolbox/kvtsampleattachmentqualitymetricskey_lumameansquarederror.md)

### Quantization

- [kVTCompressionPropertyKey_MaxAllowedFrameQP](videotoolbox/kvtcompressionpropertykey_maxallowedframeqp.md)
- [kVTCompressionPropertyKey_MinAllowedFrameQP](videotoolbox/kvtcompressionpropertykey_minallowedframeqp.md)
- [kVTCompressionPropertyKey_SpatialAdaptiveQPLevel](videotoolbox/kvtcompressionpropertykey_spatialadaptiveqplevel.md)
- [kVTCompressionPropertyKey_SupportsBaseFrameQP](videotoolbox/kvtcompressionpropertykey_supportsbaseframeqp.md)

### Rate Control

- [kVTCompressionPropertyKey_AverageBitRate](videotoolbox/kvtcompressionpropertykey_averagebitrate.md)
- [kVTCompressionPropertyKey_ConstantBitRate](videotoolbox/kvtcompressionpropertykey_constantbitrate.md)
- [kVTCompressionPropertyKey_DataRateLimits](videotoolbox/kvtcompressionpropertykey_dataratelimits.md)
- [kVTCompressionPropertyKey_EstimatedAverageBytesPerFrame](videotoolbox/kvtcompressionpropertykey_estimatedaveragebytesperframe.md)
- [kVTCompressionPropertyKey_MoreFramesAfterEnd](videotoolbox/kvtcompressionpropertykey_moreframesafterend.md)
- [kVTCompressionPropertyKey_MoreFramesBeforeStart](videotoolbox/kvtcompressionpropertykey_moreframesbeforestart.md)
- [kVTCompressionPropertyKey_Quality](videotoolbox/kvtcompressionpropertykey_quality.md)
- [kVTCompressionPropertyKey_TargetQualityForAlpha](videotoolbox/kvtcompressionpropertykey_targetqualityforalpha.md)
- [kVTCompressionPropertyKey_VariableBitRate](videotoolbox/kvtcompressionpropertykey_variablebitrate.md)
- [kVTCompressionPropertyKey_VBVBufferDuration](videotoolbox/kvtcompressionpropertykey_vbvbufferduration.md)
- [kVTCompressionPropertyKey_VBVInitialDelayPercentage](videotoolbox/kvtcompressionpropertykey_vbvinitialdelaypercentage.md)
- [kVTCompressionPropertyKey_VBVMaxBitRate](videotoolbox/kvtcompressionpropertykey_vbvmaxbitrate.md)

### Runtime Restrictions

- [kVTCompressionPropertyKey_MaxFrameDelayCount](videotoolbox/kvtcompressionpropertykey_maxframedelaycount.md)
- [kVTCompressionPropertyKey_MaxH264SliceBytes](videotoolbox/kvtcompressionpropertykey_maxh264slicebytes.md)
- [kVTCompressionPropertyKey_MaximizePowerEfficiency](videotoolbox/kvtcompressionpropertykey_maximizepowerefficiency.md)
- [kVTCompressionPropertyKey_RealTime](videotoolbox/kvtcompressionpropertykey_realtime.md)

### Temporal Scalability

- [kVTCompressionPropertyKey_BaseLayerBitRateFraction](videotoolbox/kvtcompressionpropertykey_baselayerbitratefraction.md)
- [kVTCompressionPropertyKey_BaseLayerFrameRate](videotoolbox/kvtcompressionpropertykey_baselayerframerate.md)
- [kVTCompressionPropertyKey_BaseLayerFrameRateFraction](videotoolbox/kvtcompressionpropertykey_baselayerframeratefraction.md)

### Video Extended Usage (VEXU) Signaling

- [kVTCompressionPropertyKey_HasLeftStereoEyeView](videotoolbox/kvtcompressionpropertykey_hasleftstereoeyeview.md)
- [kVTCompressionPropertyKey_HasRightStereoEyeView](videotoolbox/kvtcompressionpropertykey_hasrightstereoeyeview.md)
- [kVTCompressionPropertyKey_HeroEye](videotoolbox/kvtcompressionpropertykey_heroeye.md)
- [kVTCompressionPropertyKey_HorizontalDisparityAdjustment](videotoolbox/kvtcompressionpropertykey_horizontaldisparityadjustment.md)
- [kVTCompressionPropertyKey_HorizontalFieldOfView](videotoolbox/kvtcompressionpropertykey_horizontalfieldofview.md)
- [kVTCompressionPropertyKey_ProjectionKind](videotoolbox/kvtcompressionpropertykey_projectionkind.md)
- [kVTCompressionPropertyKey_StereoCameraBaseline](videotoolbox/kvtcompressionpropertykey_stereocamerabaseline.md)
- [kVTCompressionPropertyKey_ViewPackingKind](videotoolbox/kvtcompressionpropertykey_viewpackingkind.md)