DNG Opcodelist3 Gainmap for DJI Drones#20467
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1. Extract _parse_and_append_gain_map() from the OpcodeList2 handler to eliminate duplication and centralise GainMap parsing with debug logging 2. Log parsed GainMap fields (dimensions, planes, pitch) via DT_DEBUG_IMAGEIO 3. Update dng_gain_maps comment in dt_image_t to mention OpcodeList3 4. Add OpcodeList3 OPCODE_ID_GAINMAP handler using the new helper so that DNG files embedding GainMaps in OpcodeList3 (e.g. DJI cameras) are loaded into image->dng_gain_maps for downstream processing Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
DJI cameras (e.g. Mavic 3 Pro) embed a single RGB GainMap in DNG OpcodeList3 with planes=3, map_planes=3, row_pitch=1, col_pitch=1 instead of four per-Bayer-filter maps. The existing _check_gain_maps() only handled the 4-map Bayer format so DJI files got no flat-field correction. 1. Add _check_gain_map_rgb() to validate the single-map RGB format 2. Add logging to _check_gain_maps() rejection paths via DT_DEBUG_IMAGEIO 3. Apply RGB gainmap in process() using bilinear interpolation with FC()-based Bayer filter mapping (bl_to_plane[4]) to select the correct R/G/B plane per pixel 4. Add OpenCL kernels rawprepare_1f_gainmap_rgb and rawprepare_1f_unnormalized_gainmap_rgb in basic.cl, uploading each plane as a separate float image2d_t for GPU sampling 5. Update commit_params() to try _check_gain_map_rgb() as a fallback when the 4-map Bayer path is unavailable 6. Update reload_defaults() and gui_update() to show the Flat field control when either gainmap format is present Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Just had a first look, not bad :-)
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I have added a couple of examples here: https://gofile.me/5vUdR/4hvHNPRYi Both are DNG files and corresponding JPG straight from the Drone (ie. taken in JPEG+RAW mode). The JPG has the gainmap applied correctly by the Drone. One is a photo taken above a fjord in Norway, the other is a photo of a white paper. I tried to use the white photo as a kind of reference to adjust using masks and color calibration modules before this fix. |
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This pull request has been marked as stale due to inactivity for the last 60 days. It will be automatically closed in 300 days if no update occurs. Please verify it has no conflicts with the master branch and rebase if needed. Mention it now if you need help or give permission to other people to finish your work. |
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This PR implements support for Opcodelist 3, which is needed to get gainmap support for DNG files from drones like DJI Mini 4 Pro. Without the Gainmap, the colors are only correct in the center of the photos, and shift towards the edges, the same goes for exposure.
There is a closed issue that explains this problem, and it also includes hints about how to solve it:
#13319
This implementation was done using Claude Sonnet, and giving it the hints from the above issue and iterating until I got correct colors in DNG files from my DJI Mini 4 Pro Drone inside of Darktable.