Currently, the metadata does not appear contain a region name for faces in HEIF files. The closest that I can find is FaceID, which presumably relates to the ID of a person within digikam's database, which is meaningless outside of Digikam. It would be great if the region name could also appear somewhere within the metadata. For example: <x:xmpmeta xmlns:x='adobe:ns:meta/' x:xmptk='Image::ExifTool 12.01'> <rdf:RDF xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'> <rdf:Description rdf:about='' xmlns:apple-fi='http://ns.apple.com/faceinfo/1.0/' xmlns:mwg-rs='http://www.metadataworkinggroup.com/schemas/regions/' xmlns:stArea='http://ns.adobe.com/xmp/sType/Area#' xmlns:stDim='http://ns.adobe.com/xap/1.0/sType/Dimensions#'> <mwg-rs:Regions rdf:parseType='Resource'> <mwg-rs:AppliedToDimensions rdf:parseType='Resource'> <stDim:h>3024</stDim:h> <stDim:unit>pixel</stDim:unit> <stDim:w>4032</stDim:w> </mwg-rs:AppliedToDimensions> <mwg-rs:RegionList> <rdf:Seq> <rdf:li rdf:parseType='Resource'> <mwg-rs:Area rdf:parseType='Resource'> <stArea:h>0.083000000000000018</stArea:h> <stArea:unit>normalized</stArea:unit> <stArea:w>0.061999999999999944</stArea:w> <stArea:x>0.58200000000000007</stArea:x> <stArea:y>0.24050000000000002</stArea:y> </mwg-rs:Area> <mwg-rs:Extensions rdf:parseType='Resource'> <apple-fi:AngleInfoRoll>0</apple-fi:AngleInfoRoll> <apple-fi:AngleInfoYaw>0</apple-fi:AngleInfoYaw> <apple-fi:ConfidenceLevel>591</apple-fi:ConfidenceLevel> <apple-fi:FaceID>1</apple-fi:FaceID> <apple-fi:Timestamp>13460641474736</apple-fi:Timestamp> </mwg-rs:Extensions> <mwg-rs:Type>Face</mwg-rs:Type> </rdf:li> </rdf:Seq> </mwg-rs:RegionList> </mwg-rs:Regions> </rdf:Description> <rdf:Description rdf:about='' xmlns:photoshop='http://ns.adobe.com/photoshop/1.0/'> <photoshop:Source>2019-07-25 15-26-26</photoshop:Source> </rdf:Description> </rdf:RDF> </x:xmpmeta>
yes HEIF is a special case, because write metadata on the fly to HEIF is not yet supported. We can only update metadata if whole image is reencoded. There are bugs reported to libheif project. https://github.com/strukturag/libheif/issues/164 https://github.com/strukturag/libheif/issues/105 Another point : libexiv2, which is used normally to play with metadata on the fly do not support HEIF. Exiv2 library must be the ultimate solution to support fully HEIF metadata. In digiKam with work around this problem using libheif instead, but it's limited. Why HEIF is not supported to Exiv2 : because the team refuse to implement HEIF container (and CR3 raw file which is the same data container). https://github.com/Exiv2/exiv2/issues/1229 https://github.com/Exiv2/exiv2/issues/236 So the problem is not only relevant of face region to store in HEIF metadata. It concern all metadata writing on the fly by digiKam, aka date, orientation comments, tags, labels, gps, etc... Gilles Caulier
A work around for your problem is to use XMP sidecar files... Gilles Caulier
Thanks for the reply and apologies for the delay getting back to you. I didn't realise what a patent-encumbered mess this format is. The problem is that this is the default format of choice for Apple devices, so these things are becoming more common. It's just one more reason why my wife doesn't like her iPhone ;) It's a shame to enable sidecar files for all formats for the sake of this one troublesome format. I guess that a temporary solution could be to add an extra option in Digikam to store XMP data sidecar files where the format (HEIF) doesn't support it. At the moment, it is silently failing to write the data. I can appreciate that you might not want to go down that route: It's a bit of a hack to get around limitations in the libraries that you are using and it could end up causing work to merge them in when the capability does eventually appear in the libraries.
With digiKam 7.3.0, Windows installer will use Exiv2 0.27.4 which will include BMF (base Media Format) write support. https://en.wikipedia.org/wiki/ISO/IEC_base_media_file_format HEIF and AVIF will be supported de facto. Exiv2 0.27.4 will be released officially in few week, but digiKam pre-release installer already use this Exiv2 revision. https://files.kde.org/digikam/ Gilles Caulier
Hi, with 7.3.0 should metadata for HEIF files now be written to the file itself rather than XMP sidecar? I still see the sidecar being created (but I might have a setting wrong). I have "Write to XMP sidecar for readonly item" selected.