Magic Lantern Forum

Developing Magic Lantern => Feature Requests => Topic started by: Marsu42 on February 16, 2014, 02:21:21 AM

Title: Backend to add/remove keywords to sidecar files
Post by: Marsu42 on February 16, 2014, 02:21:21 AM
We have already got the option to add post-deflicker and dual_iso tag information to xmp sidecar files.

What I'd like to have is the option to add or remove arbitrary keywords to this file, complete with the option to create the sidecar it if it doesn't already exist - like in CheckKeyword("tag"), AddKeyword("tag") and RemoveKeyword("tag").

The front-end (which buttons to press where in what mode with what feedback) isn't the problem - but have no clue about the file r/w stuff, so it'd be great if some other dev could help out with creating these backend functions :-o

Imho it's well worth the work, the 5d3 even got the (in)famous rate button because for pj work tagging in-camera is important - so I'm sure adding the ability for more than one dimension (rating) would be widely appreciated.
Title: Re: Backend to add/remove keywords to sidecar files
Post by: a1ex on February 16, 2014, 08:48:53 AM
A backend is easy to do if somebody compiles a guide on how to add these tags, for example (also if they can have values, special meanings and so on). There are scattered bits from this forum, if anyone wants to link them from here. The XMP spec is huge, and this backend would target only a limited set of tags.

So far, it looks to me we would like to tag:
- exposure compensation (as in Post Deflicker)
- fake aperture of manual lenses
- mark dual ISO files (so you can sort them in post)
- rating?
- ???

pj = ?

I'd go for a skeleton XMP (like the post deflicker one), and for each of these functions, you'll have to post the XMP snippet required to add that tag in order to be recognized by common software (Adobe? anything else uses XMP files? are the tags universal or app-specific?)
Title: Re: Backend to add/remove keywords to sidecar files
Post by: Audionut on February 17, 2014, 04:48:24 AM
It's an ISO standard.

http://partners.adobe.com/public/developer/en/xmp/sdk/XMPlicense.txt

There is an SDK available:  http://blogs.adobe.com/gunar/2007/05/xmp_411_sdk_available_under_bsd_license.html
Title: Re: Backend to add/remove keywords to sidecar files
Post by: Marsu42 on February 17, 2014, 07:36:50 AM
Quote from: a1ex on February 16, 2014, 08:48:53 AM
- rating?

Rating simply is the following line, but we could leave it to the Canon software as this works (somehow) with key emulation and the rating-stars are displayed as an overlay. You can also filter by Canon stars in the slideshow, so if ML tries to do something about this the rating would have to go into the cr2/jpg header, not into the xmp only.

xmp:Rating="5"

Quote from: a1ex on February 16, 2014, 08:48:53 AM
pj = ?

Photojournalism :-) ... for each new keyword, simply add another tag line to the correct place just like it already exists the deflick xmp skeleton.


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