Is xmp:rating=-1 (rejected) standard or not?

[RobiWan]

Hi,

I can't find informations if xmp:rating=-1 standard tag is or not. If someone has maybe a link for me

Robert

[Mario]

Just look at the XMP specification?
https://github.com/adobe/XMP-Toolkit-SDK/blob/main/docs/XMPSpecificationPart1.pdf

From the spec:

Rating: A user-assigned rating for this file. The value shall be -1 or in the range
[0..5], where -1 indicates "rejected" and 0 indicates "unrated". If xmp:Rating
is not present, a value of 0 should be assumed.
NOTE Anticipated usage is for a typical "star rating" UI, with the addition of a notion of rejection

Why do you want to know?

[RobiWan]

Why do you want to know?

I asked this to implement by ON1, Capture One and DxO. ON1 and Dxo tells - it's not standard

[Mario]

I asked this to implement by ON1, Capture One and DxO. ON1 and Dxo tells - it's not standard

It's definitely part of the XMP standard. Allowed ratings are [0-5] and -1.

But image editing companies usually don't care much for standards.
Handing metadata correctly is hard and does not show in flashy ads or standard reviews on photographer web sites and boards. Marketing usually directs developer resources to other things, not standard-compliant metadata handling.

[RobiWan]

Handing metadata correctly is hard

May be true but I can't understand why companies like ON1 or DxO impelemnts things like "like" or "reject" as " traffic lights" which are not part of XMP standard

[Mario]

The standard does not specify how an application should implement a rating feature (or a label feature).

It just says: NOTE Anticipated usage is for a typical "star rating" UI, with the addition of a notion of rejection.

There is no MUST or SHOULD requirement and so application vendors are free to do whatever they like. Whatever their UX people come up with. A star rating is the most obvious solution, though.

Important is that the user is clearly able to tell which "rating thingie" is better and when a file was "rejected" (if this makes sense in the application). And that the rating is written correctly into the XMP metadata so other applications can see it.