RFExportPresetName QTMovie4K QTExpComponentExtension mov QTExpType Export MaximumSize 3840, 2160 MGAVExportPresetIdentifier AVAssetExportPreset3840x2160 MGAVExportHEVCPresetIdentifier AVAssetExportPresetHEVC3840x2160 MGAVExportAlphaPresetIdentifier AVAssetExportPresetHEVC3840x2160WithAlpha