About "Rec. 709" vs "BT.709" naming convention.

[KelSolaar]

This one has been itching me for a while and a discussion thread on 3D-Pro raised it up in the priority stack. Initially we have been using Rec. 709/Rec. 2020 as colourspace names. Then when we split the transfer functions into their own sub-package, we started naming them using BT.709, BT.2020, BT.1886 and this is the way I would have been keen on naming stuff for consistency.

Some examples names:

• Rec. 709
• BT.709 <--- One I'm keen on using
• ITUR_709 <--- Apple
• BT709 <--- Google
• ITU-RBT709 <--- ICC

[zachlewis]

Have you considered / are you aware of the nomenclature used in the official SMPTE Metadata Registers? They seem to be using "ITU709" and "ITU-R BT.709" for Symbols and Names, respectively: https://registry.smpte-ra.org/view/published/labels_view.html

(Probably for a different thread, but it couldn't hurt to have references to appropriate SMPTE URNs; i.e., urn:smpte:ul:060e2b34.04010101.04010101.01020000)

[KelSolaar]

@zachlewis : Good find!

I have extracted a row for further discussion:

Symbol	Namespace	UL	Kind	Name	Definition	Applications	Notes	Defining Document	Is Deprecated
TransferCharacteristic_ITU709	http://www.smpte-ra.org/reg/400/2012	urn:smpte:ul:060e2b34.04010101.04010101.01020000	LEAF	ITU-R BT.709 Transfer Characteristic	Identifies ITU-R BT.709 transfer characteristic (also used in SMPTE 170M, 274M and 296M)			ITU-R BT.709	false

My preference is for either:

• BT.709
• ITU-R BT.709

[meshula]

For the record, here's all of Apple's named color spaces.

https://developer.apple.com/documentation/coregraphics/cgcolorspace

The actual name is ITU-R BT.709

https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.709-6-201506-I!!PDF-E.pdf

I'm inclined to the long name.

[KelSolaar]

Thanks Nick!