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[AI] Fix raw denoise output corrupted DNG / process crash on some libtiff builds #20898

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Merged
TurboGit merged 2 commits into from
Apr 29, 2026
+44 −5
Merged

[AI] Fix raw denoise output corrupted DNG / process crash on some libtiff builds #20898

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100a72c
Fix corrupt DNG on libtiff builds that drop CFA tag info across SubIF…
andriiryzhkov Apr 29, 2026
d5af7b6
Add libtiff error handlers in DNG writer to avoid third-party handler…
andriiryzhkov Apr 29, 2026
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49 changes: 44 additions & 5 deletions src/imageio/imageio_dng.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,38 @@
// these as float/double arrays and handles the conversion; we just pass
// the values as double

// libtiff error/warning handlers — replacing whatever else in the
// process may have installed (e.g. ImageMagick's, which crashes on
// NULL exception context). these just log to stderr and never abort
static void _dt_dng_tiff_warning(const char *module,
const char *fmt, va_list ap)
{
if(darktable.unmuted & DT_DEBUG_IMAGEIO)
{
fprintf(stderr, "%11.4f [imageio_dng] warning: %s: ",
dt_get_wtime() - darktable.start_wtime,
module ? module : "(none)");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}
}

static void _dt_dng_tiff_error(const char *module,
const char *fmt, va_list ap)
{
fprintf(stderr, "%11.4f [imageio_dng] error: %s: ",
dt_get_wtime() - darktable.start_wtime,
module ? module : "(none)");
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
}

static void _install_dng_tiff_handlers(void)
{
TIFFSetWarningHandler(_dt_dng_tiff_warning);
TIFFSetErrorHandler(_dt_dng_tiff_error);
}

// map the dcraw 2x2 CFA filters word to 4 single-byte channel indices
// for the DNG CFAPattern tag: 0=R, 1=G, 2=B, following DNG spec §A.3.1
static void _cfa_bytes_from_filters(uint32_t filters, uint8_t out[4])
Expand Down Expand Up @@ -160,6 +192,8 @@ int dt_imageio_dng_write_cfa_bayer(const char *filename,
if(!filename || !cfa || !img || width <= 0 || height <= 0)
return 1;

_install_dng_tiff_handlers();

#ifdef _WIN32
wchar_t *wfilename = g_utf8_to_utf16(filename, -1, NULL, NULL, NULL);
TIFF *tif = TIFFOpenW(wfilename, "wl");
Expand All @@ -184,10 +218,11 @@ int dt_imageio_dng_write_cfa_bayer(const char *filename,
g_unlink(filename);
return 1;
}
// libtiff entered INSUBIFD mode when the IFD0 carrying TIFFTAG_SUBIFD
// was written; subsequent TIFFSetField + scanline writes populate
// the SubIFD without an explicit TIFFCreateDirectory call (whose
// return-value convention changed between libtiff versions)
// re-register default tag info on some libtiff builds CFA/DNG
// extension tags would be lost across the IFD write, breaking
// CFAREPEATPATTERNDIM / CFAPATTERN. return value differs across
// libtiff versions; not checked
TIFFCreateDirectory(tif);
}

// raw payload IFD: single IFD when no preview, otherwise SubIFD0
Expand Down Expand Up @@ -299,6 +334,8 @@ int dt_imageio_dng_write_linear(const char *filename,
if(!filename || !rgb || !img || width <= 0 || height <= 0)
return 1;

_install_dng_tiff_handlers();

#ifdef _WIN32
wchar_t *wfilename = g_utf8_to_utf16(filename, -1, NULL, NULL, NULL);
TIFF *tif = TIFFOpenW(wfilename, "wl");
Expand All @@ -321,7 +358,9 @@ int dt_imageio_dng_write_linear(const char *filename,
g_unlink(filename);
return 1;
}
// libtiff is in INSUBIFD mode after IFD0 was written with TIFFTAG_SUBIFD
// re-initialize directory state so DNG extension tag info is
// available on the SubIFD (see comment in write_cfa_bayer)
TIFFCreateDirectory(tif);
}

// baseline TIFF tags, 3 samples per pixel (demosaicked)
Expand Down