[AI] Fix raw denoise output corrupted DNG / process crash on some libtiff builds

[andriiryzhkov]

Fixes two symptoms reported in #20854 (comment):

• Re-imported denoised DNG flagged as corrupt by rawspeed (Entry 0x828d not found)
• Hard process crash (ThrowLoggedException assertion in ImageMagick) on some images, in both CPU and MIGraphX modes

Both trace to libtiff CFA / DNG extension tag info handling on the SubIFD in the canonical Adobe layout (IFD0 = JPEG preview, SubIFD0 = raw payload) introduced in #20854.

Fixes

1. Re-initialize SubIFD tag info. After TIFFWriteDirectory(IFD0), some libtiff packagings drop the registered field info for CFA / DNG extension tags. The next TIFFSetField(TIFFTAG_CFAREPEATPATTERNDIM, ...) then silently fails - producing a DNG without the CFA pattern that rawspeed can't decode. One-line fix: call TIFFCreateDirectory(tif) between IFD0 commit and SubIFD population. Applied in both dt_imageio_dng_write_cfa_bayer and dt_imageio_dng_write_linear. No-op on libtiff builds that already retained the tag info.

2. Install our own libtiff error/warning handlers. When the unknown-tag error fires on systems where ImageMagick has installed itself as the global libtiff error handler, ImageMagick's TIFFReadErrors calls ThrowLoggedException(NULL, ...) and aborts. Same pattern as imageio_tiff.c already uses: handlers log to stderr and never abort, overriding whatever else is in the process.

[TurboGit]

Looks good to me, thanks!

[da-phil]

@andriiryzhkov unfortunately this didn't fix the issue, this is the current output:

2026-04-30 00:15:49.328086631 [W:onnxruntime:DarktableAI, migraphx_execution_provider.cc:167 MIGraphXExecutionProvider] [MIGraphX EP] MIGraphX ENV Override Variables Set:
    70.7493 [neural_restore] raw preview: full=5240x3912 ori=0x0 patch_center=(0.500,0.500) -> sensor=(2244,1678 752x556) bayer
    72.5724 [neural_restore] raw preview: inference returned err=0 src=0x76c2b8a8d010 denoised=0x76c2b6373010 requested=752x556 actual=719x532
    73.7113 [neural_restore] job started: task=raw denoise, scale=1, images=1
    73.7114 [neural_restore] processing imgid 31758 -> /home/phil/Pictures/20170606_072239_raw-denoise.dng
    73.7114 [neural_restore] imgid 31758: flags=0x643 channels=1 filters=0x94949494 (bayer)
    73.7668 [restore_raw_bayer] 5240x3912 sensor (CFA origin 0,0), working 2620x1956 packed, tile T=2048, 2x1 grid (2 tiles)
    73.7704 [restore_raw_bayer] raw CFA range [258.0, 3545.0], black=[257,257,257,257] white=4003 wb_coeffs=[492.000,256.000,484.000,0.000] wb_norm=[1.000,1.000,1.000]
    73.8321 [restore_raw_bayer] tile0 model_input range R=[0.000,0.293] G1=[0.001,0.545] G2=[0.001,0.545] B=[0.000,0.273]
    74.8804 [restore_raw_bayer] tile0 model_output range R=[0.001,0.335] G=[0.002,0.647] B=[0.001,0.346] in_mean=0.074 out_mean=-60034606.923 gain=-1.237e-09
    75.9218 [restore_raw_bayer] cfa_out u16 range [260, 3882] mean=677 (DNG will advertise black~257 white=4003)
    75.9415 [neural_restore] embedded JPEG preview from source 3200x2400 (1000782 bytes)
    75.9578 [imageio_dng] error: TIFFSetField: /home/phil/Pictures/20170606_072239_raw-denoise.dng: Unknown tag 33421
    75.9578 [imageio_dng] error: TIFFSetField: /home/phil/Pictures/20170606_072239_raw-denoise.dng: Unknown tag 33422
    76.4479 [neural_restore] imported imgid=63602: /home/phil/Pictures/20170606_072239_raw-denoise.dng
   278.3986 [rawspeed] 20170606_072239_raw-denoise.dng corrupt: rawspeed::RawImage rawspeed::RawDecoder::decodeRaw(), line 334: rawspeed::TiffEntry* rawspeed::TiffIFD::getEntry(rawspeed::TiffTag) const, line 316: Entry 0x828d not found.

As I mentioned I am running libtiff-4 in version 4.5.1, which one are you using on your machine?

[andriiryzhkov]

Do you have the same error on nightly build?