JXL DNG: honor Row/ColumnInterleaveFactor, add F32 path#1
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DNG 1.7 CFA files may store the Bayer mosaic as RowInterleaveFactor x ColumnInterleaveFactor stacked color-plane "fields" (each a smooth half-res subimage that compresses far better under lossy JPEG XL), signalled by tags 0xC71F / 0xCD43. rawspeed assembled the tiles but never wove the fields back together, emitting a scrambled mosaic (four quadrant planes stacked instead of RGGB). Add a whole-frame de-interleave post-pass in decodeData(), run after slices.decompress() and before handleMetadata() applies ActiveArea / DefaultCropOrigin. It operates on the uncropped assembled buffer, one whole pixel (getBpp() bytes) at a time, so it is type-generic over UINT16 and F32. A single JXL tile can straddle a field boundary, so this cannot be done per-tile. The stored->final index math (dngDeinterleaveFieldMap) follows the Adobe DNG 1.7.1.0 spec and the dng_sdk dng_read_image.cpp reference: field f's rows scatter to final rows f, f+R, f+2R, ...; non-divisible sizes let earlier fields absorb the remainder. Factored into a small pure header (DngDeinterleave.h) so the index mapping is unit-testable. R==1 && C==1 fast-paths to a no-op. Also adds the missing COLUMNINTERLEAVEFACTOR (0xCD43) tag. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Unit-test dngDeinterleaveFieldMap, including the verified 4x4 R=C=2 worked example (quadrant-constant stored buffer must de-interleave to the RGGB-phase mosaic), the per-pixel stored->final map, the factor-1 identity fast path, and the non-divisible remainder rule from dng_sdk (total=5,factor=2 and total=7,factor=3). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The decompressor unconditionally wrote the decoded tile through mRaw->getU16DataAsUncroppedArray2DRef() and requested JXL_TYPE_UINT16, which asserts (dataType == RawImageType::UINT16) and fails to decode for float (F32) JPEG XL DNGs such as Adobe's 02_jxl_linear_raw_float.dng. Pick the JxlPixelFormat sample type from mRaw->getDataType(): request JXL_TYPE_FLOAT and write via getF32DataAsUncroppedArray2DRef() for F32 images, keeping the JXL_TYPE_UINT16 path for integer images. The decoded tile now lands in a type-agnostic byte buffer (libjxl reports the size in bytes) and a templated copyTile() shares the interleaved copy loop. Verified both 01_jxl_linear_raw_integer.dng and 02_jxl_linear_raw_float.dng decode without crashing via rstest. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Stacked on top of darktable-org#971 (base branch
jpegxl-dng17). Three correctness fixes for the JPEG XL DNG decoder, found while verifying the feature against Adobe's DNG SDK sample files and a real interleaved-CFA capture.1. Honor RowInterleaveFactor / ColumnInterleaveFactor (DNG 1.7)
DNG 1.7 lets a CFA mosaic be stored as
RxCstacked half-res color-plane subimages (each plane is spatially smooth, so it compresses far better under lossy JXL). The decoder ignoredRowInterleaveFactor(0xC71F, was defined but never read) andColumnInterleaveFactor(0xCD43, was not defined), so any 2x2-interleaved CFA JXL DNG decoded scrambled: the four quadrant planes were left stacked instead of woven back into the Bayer mosaic.COLUMNINTERLEAVEFACTOR = 0xCD43toTiffTag.h.DngDeinterleave.h: pure, unit-testabledngDeinterleaveFieldMap(total, factor).DngDecoder::deinterleaveFields(): a whole-frame post-pass afterslices.decompress(), beforeActiveArea/DefaultCropOrigin. Type-generic (UINT16 + F32) viagetByteDataAsUncroppedArray2DRef().Why whole-frame, not per-tile: Adobe's
03_jxl_bayer_raw_integer.dngis 10240x7168 with 1280x1440 tiles and R=C=2; the row-field boundary (3584) is not a multiple of 1440, so a single JXL tile straddles two color planes. Per-tile de-interleave is geometrically impossible. The index mapping (fy = within_field_row * R + field_row_index, symmetric for columns; non-divisible fields let earlier fields absorb the remainder) matches the DNG 1.7.1.0 spec anddng_sdk'sdng_row_interleaved_image::MapRow.2. Unit test for the de-interleave math
googletest covering factor-1 identity, non-divisible field sizing, and the spec's 4x4 / R=C=2 quadrant worked example (verifies the exact RGGB-phase mosaic).
3. F32 output path for float JXL DNGs
The decoder unconditionally requested
JXL_TYPE_UINT16and wrote throughgetU16DataAsUncroppedArray2DRef(), which asserts on float (F32) images, so float LinearRaw JXL DNGs (02_jxl_linear_raw_float.dng) failed to decode. Now theJxlPixelFormatsample type and output accessor are picked frommRaw->getDataType()(JXL_TYPE_FLOAT+ F32 accessor for float, UINT16 path otherwise) via a templatedcopyTile().Verification (libjxl 0.11.2, standalone build)
DngDeinterleaveTest6/6.rstest -cdecodes01_jxl_linear_raw_integer,02_jxl_linear_raw_float,03_jxl_bayer_raw_integerwith no crash/assertion.02confirms the UINT16 assertion is gone.03mosaic de-scrambled: mid-line vs interior mean-abs-diff ratio 1.3x (a scrambled 4-quadrant layout shows 5-20x).Test files: the Adobe DNG SDK sample set (
adobe-dng-sdksample_files),03_jxl_bayer_raw_integer.dngbeing the canonical 2x2-interleaved CFA vector.🤖 Generated with Claude Code