@kmilos I lived and worked in the States before I retired in England. I have only a vague idea about the location of the countries behind the iron curtain. One day we’ll have a road trip.
Good news from the tests: I have investigated the XMP puzzle and can’t find XMP in those files either. My code extracts the ICC profile from lilienstein_1k_HLG_icc.avif. So everything looks fine.
Bring your wife and toddler. I’m thinking of a cabin in the woods. My wife will come. Our toddlers are now 44 and 45, and have to stay home to supervise the teenage grand-kids.
I looked at Tomsk_with_thumbnails.avif. It’s a small file. Looks like the image+2 thumbs are in sequence of ‘info’ boxes. The offset/length of those objects are in the iloc box.
518 rmills@rmillsm1:~/gnu/github/av1-avif-master/testFiles/Microsoft $ ls -l T*
-rw-r--r--@ 1 rmills staff 10864 8 Feb 09:31 Tomsk_with_thumbnails.avif
519 rmills@rmillsm1:~/gnu/github/av1-avif-master/testFiles/Microsoft $ exiv2 -pS Tomsk_with_thumbnails.avif
...
Exiv2::BmffImage::boxHandler: infe 105->21 ID = 1 av01
Exiv2::BmffImage::boxHandler: infe 126->21 ID = 2 av01
Exiv2::BmffImage::boxHandler: infe 147->21 ID = 3 av01
Exiv2::BmffImage::boxHandler: infe 168->21 ID = 4 Exif *** Exif ***
Exiv2::BmffImage::boxHandler: iloc 189->72
197 | 14 | ID | 1 | 1775, 7618
211 | 14 | ID | 2 | 9393, 1409
225 | 14 | ID | 3 | 564, 1211
239 | 14 | ID | 4 | 10802, 62
...
Alex and I have investigated how darktable handles thumbnails and it generates and caches them without using Exiv2::Preview. Exiv2 will not provide Preview/thumbnail support for bmff. Exiv2::Preview only handles previews stored in Exif, so its use is limited. If an avif file stored a thumbnail in Exif, it would be respected.
When the bmff PR has been reviewed and merged, I’ll proceed to prepare Exiv2 v0.27.4 RC1.
I hope it’s not forbidden to cross-post in two Pixels.us forums. I promise not to abuse this.
I have downloaded 2.10.30 to my Apple M1 MacBook Pro running Big Sur, and I cannot find the option for exporting an image as AVIF, as described on many web sites, include the Gimp official site: GIMP 2.10.22 Released - GIMP. I also tried downloading 2.99.8. It doesn’t seem to offer the option either. Also, I cannot load an .avif image into either of these versions of gimp. Specifically, I tried one of the .avif test files here: https://github.com/AOMediaCodec/av1-avif/tree/master/testFiles/Microsoft (recommended in another Pixls.us Gimp forum), and received a popup error saying “Unknown file type”, suggesting that they don’t support AVIF files. Am I doing something wrong? Has AVIF support been removed? Is it the fact that I’m using a Mac?
