Hi.
I’m using a Nikon D500 and have encountered some files that fails to load in darktable, due to failure to load the camera’s White Balance.
I have done some testing and it looks like I am able to “force” the failure of getting the camera white balance within darktable for images with 14-bit Lossy Compression if the ISO value is higher than 25600.
Lossless Compression, or uncompressed, does not seem to suffer from the same problem.
I can not say that this is the cause of the problem, but it could be worth pursuing.
Hopefully someone else can test with another camera and see if they have the same problem.
My darktable version is 2.4.1 (had the same problem with earlier versions too.)
D500 firmware: C=1.13 / LD=2.016 / W=3.00
4 images with different ISO-settings shows like this using exiftool:
$> find -iname *.nef -print0 | sort -z | xargs -0 exiftool -compression* -nefcompression -bitspersample -iso
======== ./_5001196.NEF
Compression : Nikon NEF Compressed
NEF Compression : Lossy (type 2)
Bits Per Sample : 14
ISO : 64508
======== ./_5001197.NEF
Compression : Nikon NEF Compressed
NEF Compression : Lossy (type 2)
Bits Per Sample : 14
ISO : 51200
======== ./_5001198.NEF
Compression : Nikon NEF Compressed
NEF Compression : Lossy (type 2)
Bits Per Sample : 14
ISO : 25600
======== ./_5001199.NEF
Compression : Nikon NEF Compressed
NEF Compression : Lossy (type 2)
Bits Per Sample : 14
ISO : 6400
Upon opening darktable this is shown in the console:
[rawspeed] (_5001196.NEF) void rawspeed::HuffmanTable::setCodeValues(const rawspeed::Buffer&), line 176: Corrupt Huffman. Code value 92 is bigger than 16
[temperature] failed to read camera white balance information from `_5001196.NEF'!
allocation failed???
[rawspeed] (_5001197.NEF) void rawspeed::HuffmanTable::setCodeValues(const rawspeed::Buffer&), line 176: Corrupt Huffman. Code value 92 is bigger than 16
[temperature] failed to read camera white balance information from `_5001197.NEF'!
allocation failed???As we can see, ISO 25600 and below does not show an error. Higher than 25600 produces the error and the file will not open in darktable.
Is the same code, (rawspeed::HuffmanTable::setCodeValues(const rawspeed::Buffer&)), executed if the file is Lossless Compressed, or 12-bit?
Lossless and 12-bit seem to work with higher ISO-values, so the problem looks a bit inconsistent.
I can upload the 4 images referred to above if it will help resolve this issue.
Just let me know.