[digiKam-users] DK inquiry
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DK 6.4.0 appimage.
When I close DK, DK writes " the stuff" to the XMPs. What's the downside or the implications of not using the XMPs? -- sknahT vyS |
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By "the stuff" I guess you mean the metadata. And by the "XMPs" I guess you
mean sidecar files. If you don't use XMP sidecars, the metadata will either be saved within each picture file, or not saved at all (depending on your digikam settings). Saving metadata to the image is slower, since the whole file has to be read and written, and each write operation entails a risk of corrupting the picture file (although that has never happened to me). Also, there's the risk of overwritting existing metadata if you are not careful. Using XMP sidecars leaves the image intact, and it is much faster since it's only a few Kilobytes that have to be read/written for each picture. The dowside of using XMP sidecars is that picture folders get crowded with these small files, and some people can find that annoying. Some picture software might not be compatible with sidecars, so they will read the metadata from the picture only, which might contain conflicting information. Also, if you share these picture files without the sidecars, the other person won't have all the metadata. And if you use neither... well, the day you want to use any software other than digikam, all changes would be lost and you would need to tag everything again. -- Sent from: http://digikam.1695700.n4.nabble.com/digikam-users-f1735189.html |
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On Wed, 20 Nov 2019 13:54:24 -0600 (CST)
woenx <[hidden email]> wrote: > By "the stuff" I guess you mean the metadata. And by the "XMPs" I > guess you mean sidecar files. Thanks for correcting my English. English not my first, nor second language... Yes, I mean sidecars with the XMP data like tags and descriptions. The EXIF data is already in the raw file. > > If you don't use XMP sidecars, the metadata will either be saved > within each picture file, or not saved at all (depending on your > digikam settings). * Are the XMP sidecars "standard" (whatever standard means, I'm not sure)? * Do all imaging software read the XMP sidecars? * Can they all read the tags and the descriptions from the XMP sidecars? > > Saving metadata to the image is slower, since the whole file has to > be read and written, and each write operation entails a risk of > corrupting the picture file (although that has never happened to > me). Also, there's the risk of overwritting existing metadata if > you are not careful. Using XMP sidecars leaves the image intact, > and it is much faster since it's only a few Kilobytes that have to > be read/written for each picture. > > The dowside of using XMP sidecars is that picture folders get > crowded with these small files, and some people can find that > annoying. Some picture software might not be compatible with > sidecars, so they will read the metadata from the picture only, > which might contain conflicting information. Also, if you share > these picture files without the sidecars, the other person won't > have all the metadata. > > And if you use neither... well, the day you want to use any > software other than digikam, all changes would be lost and you > would need to tag everything again. > > > > -- > Sent from: > http://digikam.1695700.n4.nabble.com/digikam-users-f1735189.html -- sknahT vyS |
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digikam-2 wrote
> Thanks for correcting my English. English not my first, nor second > language... Don't worry, neither is mine :) digikam-2 wrote > * Are the XMP sidecars "standard" (whatever standard means, I'm not > sure)? > * Do all imaging software read the XMP sidecars? > * Can they all read the tags and the descriptions from the XMP > sidecars? According to wikipedia https://en.wikipedia.org/wiki/Extensible_Metadata_Platform XMP seems to be a standard, and it can be written in a sidecar file, or directly in the picture file, next to the Exif and IPTC metadata. In the wiki article there's a list of software that supports XML, but it doesn't specify if they use sidecars, or they embed the XMP information in the picture. I know first-hand that Adobe Lightroom / Bridge, Darktable and ACDSee both are compatible with XMP sidecars. Not sure about others, but these are some of the main ones. I think that, in theory, the EXIF metadata can also be saved in the XMP sidecar files. Although I am not sure how that works. -- Sent from: http://digikam.1695700.n4.nabble.com/digikam-users-f1735189.html |
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On mercredi 20 novembre 2019 22:00:11 CET woenx wrote:
> digikam-2 wrote > > > Thanks for correcting my English. English not my first, nor second > > language... > > Don't worry, neither is mine :) > > digikam-2 wrote > > > * Are the XMP sidecars "standard" (whatever standard means, I'm not > > sure)? > > > > * Do all imaging software read the XMP sidecars? > > * Can they all read the tags and the descriptions from the XMP > > sidecars? > > According to wikipedia > https://en.wikipedia.org/wiki/Extensible_Metadata_Platform XMP seems to be a > standard, and it can be written in a sidecar file, or directly in the > picture file, next to the Exif and IPTC metadata. In the wiki article > there's a list of software that supports XML, but it doesn't specify if > they use sidecars, or they embed the XMP information in the picture. I know > first-hand that Adobe Lightroom / Bridge, Darktable and ACDSee both are > compatible with XMP sidecars. Not sure about others, but these are some of > the main ones. > > I think that, in theory, the EXIF metadata can also be saved in the XMP > sidecar files. Although I am not sure how that works. > > -- > Sent from: http://digikam.1695700.n4.nabble.com/digikam-users-f1735189.html XMP is an ISO standard (a form of XML), but the tags are not all described in the standard. XMP tags are organised in namespaces, which can be defined by anyone, and used by anyone as long as the definition is accessible. Each program decides which namespaces to use. One of those namespaces is "exif" (xmlns:exif="http://ns.adobe.com/exif/ 1.0/"), which records the exif metadata. In a similar way, IPTC metadata can also be included in XMP files. Similarly, digikam, darktable, and adobe and others have defined namespaces (see the attributes starting with "xmlns:", which stands for XML NameSpace). You can safely open a sidecar with a text editor (Vi, notepad, ..., do *not* use a word processor!) to have a look. The use of third-party namespaces is why your digikam tags/keywords appear several times*. Normally, any program that writes XMP sidecars can also read them (and vice versa). But reading the sidecar isn't enough, the program has to be able to use the data, so it must understand the namespaces used by the programs that wrote the sidecar. That's what causes the "missing data" when using several programs. Normally, such metadata should be ignored, and kept unchanged in the sidecar file, but that can be delicate if the sidecar is rewritten. Remco *: I use digikam and darktable, and between the two I see 14 namespaces used in the XMP files, and the keywords I assigned appear 5 times (at least): 3x in a hierachical form, once as a simple list, and once as encoded xml (for acdsee). |
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