Cropped dimensions mismatch

Submitted by jtomori on

Hello,
while testing https://github.com/letmaik/rawpy/pull/252 I've noticed some inconsistencies and would like to ask about them here. I suspect some might be bugs.

When checking dimensions of this image https://data.csail.mit.edu/graphics/fivek/img/dng/a0001-jmac_DSC1459.dng, LibRaw's dimensions are off by one.

LibRaw (0.21.3): 3007 x 1999 left: 16 top: 8
Checked with raw-identify -v and looked for line starting with Raw inset, width x height:.

ExifTool:

[TIFF-IFD0-SubIFD] DefaultCropOrigin            : 15 7
[TIFF-IFD0-SubIFD] DefaultCropSize              : 3008 2000

Checked with exiftool -a -G5 -s. (exiv2 reports the same values)

Best,
Juraj

Forums: 

Another issue I came across

Submitted by jtomori on

Another issue I came across is that the cropped dimension offsets are different between a CR2 image and a corresponding DNG.

CR2: https://github.com/letmaik/rawpy/blob/main/test/RAW_CANON_5DMARK2_PREPRO... and a DNG is obtained by using Adobe DNG Converter (17.1.0).

CR2: 5616 x 3744 left: 168 top: 56
DNG: 5616 x 3744 left: 336 top: 112

CR2's raw resolution is 5792x3804, so trying to crop it according to those values would not be possible - it'd escape the raw dimensions (e.g. 336 + 5616 > 5792).

It's also interesting that DNG's offsets are exactly double of those reported for CR2.

I found a note here https://www.libraw.org/news/libraw-202110-snapshot that this might be expected, but wanted to flag it anyway in case it'd offer you some additional clues.

Left/top margins are always

Submitted by lexa on

Left/top margins are always adjusted to multiply of 2 (of 6 for Fuji X-Trans) to keep bayer pattern the same for both full sensor area and visible area.

-- Alex Tutubalin @LibRaw LLC

Ah, that makes sense about

Submitted by jtomori on

Ah, that makes sense about the left/top margins to align with bayer pattern.

What about the cropped resolution though? Shouldn't it match what ExifTool reports? E.g. LibRaw's 3007 x 1999 vs ExifTool's 3008 x 2000.

I'm wondering if the decreased resolution is caused by the left/top alignment, or it's an unrelated issue.

If left (or top) margin is

Submitted by lexa on

If left (or top) margin is adjusted by one: this results into visible area adjustment too...

-- Alex Tutubalin @LibRaw LLC

Regarding RAW_CANON_5DMARK2

Submitted by lexa on

Regarding RAW_CANON_5DMARK2_PREPROD.CR2 file:
1) Converted it to DNG using current Adobe DNG Converter (17.2)
2) processed w/ dcraw_emu -T -w (dcraw_emu: from github/LibRaw/master)

Results are the same in size, 5634x3752
TIFF from CR2: https://www.dropbox.com/scl/fi/61ug0bh598av2plhbgheq/RAW_CANON_5DMARK2_P...

TIFF from DNG: https://www.dropbox.com/scl/fi/c97oua0z5vpiaksnhk418/RAW_CANON_5DMARK2_P...

-- Alex Tutubalin @LibRaw LLC

Framing is also the same:

Submitted by lexa on

Framing is also the same:
$ raw-identify -f -u *

RAW_CANON_5DMARK2_PREPROD.CR2 lossless_jpeg_load_raw() F=158x52x0x0 RS=5792x3804 Canon/EOS 5D Mark II
RAW_CANON_5DMARK2_PREPROD777.dng packed_dng_load_raw() F=158x52x0x0 RS=5792x3804 Canon/EOS 5D Mark II

-- Alex Tutubalin @LibRaw LLC

Thanks for your replies and

Submitted by jtomori on

Thanks for your replies and for looking into it (and for the library as well).

To add to the DNG, CR2 question - you are right - TIFF from DNG and TIFF from CR2 have matching resolution 5634x3752 which seems to map to width, height from the libraw_image_sizes_t structure.

Also raw-identify -f -u reports the same raw_height, raw_width resolutions for both DNG and CR2: 5792x3804.

What is differing is the line starting with Raw inset, width x height: matching libraw_raw_inset_crop_t when using raw-identify -v on both DNG and CR2: offsets in CR2 are 168, 56 and for DNG are 336, 112. The DNGs offsets are too large - e.g. trying to crop raw area with them would not be possible. I think I'd expect offsets of both DNG and CR2 match (cropped resolution matches).

Thanks: look like a bug:

Submitted by lexa on

Thanks: look like a bug: inset_crop ajusted twice: DNG metadata (DefaultCrop tag) and Canon visible area metadata.

-- Alex Tutubalin @LibRaw LLC