LibRaw technical support

Stable LibRaw versions: technical support, errors, API questions

Which aces colorspace is defined in -o 6

Submitted by jt042 on

Hello,

a professor introduced me to libraw because I need to convert my raw files to linear tiff in a defined colorspace.
In the dcraw manpage you can find the argument -o 6 for ACES.
But what aces colorspace is ment by this?
AP1 seems to be a bit to greenish and ap0 a bit to red, but this is only in comparison to my memory.
I attached contact sheet that compares the two here https://ufile.io/chi40f32

Also, is there a way to extract the exact color matrix that is embedded in the .cr2 raw files?

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Edit EXIF data using external library

Submitted by aprofiti on

I would like to know if it's possible to use libraw to edit exif related metadata, by passing data structure to some other library like libexif or similar.

I'm interested in changing Lens related information (name, id, type...), aperture and focal length inside a CR2 file.
.
I had a look to the documentation and found that libraw parse metadata and save the above info in libraw_lensinfo_t and libraw_makernotes_lens_t; if I understand right they are read-only but is possible to install hook for EXIF data when parsing file.

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LibRaw (dcraw?) orientation tag wrong?

Submitted by Mabula on

Hi team,

I am starting to use LibRaw for my own software package (Astro Pixel Processor). I have already written full metadata extraction of TIFF IFDs, EXIF & Makernote tags and Raw conversion of both Canon CR2 and Nikon NEF files.

I have now started with building LibRaw support into my software using Java JNI and I am testing this now on Sony ARW files.

I am able to retreive the Sony arw raw data and I am also able to get certain important metadata values like exposure time, time of exposure, iso etc...

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CMYK Raw Image Data

Submitted by pablobhz on

Hello.
I've tried FastRawViewer and an python libraw(rawpy) parser for reading some CMYK raw image data.
However, none of them was able to read my file.

Until now the only way i've found to read this file is by using Photoshop (opening it there renamed as .raw).
I uploaded a sample of the file i mentioned to google drive:
It is a GrayScale 1-Channel file. Dimensions 305wx374h.

https://drive.google.com/file/d/1NHgeJtGw3tZS7IJFJYpJYg-Tkb9lMlc1/view?u...

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guidance needed to improve image quality

Submitted by kornelix on

I implemented the simple generic decode using the dcraw model. I see that the resulting image quality is sometimes fine, sometimes problematic (brightness and color conversion incorrect). What am I missing? Am I expected to understand each camera's characteristics and add post-processing to correct the image?

Outline of implementation:

librawdata->params.use_camera_wb = 1;
librawdata->params.output_color = 1;
err = libraw_dcraw_process(librawdata);
RAWimage = libraw_dcraw_make_mem_image(librawdata,&err);

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I still get LIBRAW_THUMBNAIL_UNKNOWN from master branch

Submitted by Kuro on

I got the latest master branch, and when I decode the thumbnail for newer cameras such as Sony A73 and Fuji X-H1, thumbnail.tformat still returns LIBRAW_THUMBNAIL_UNKNOWN.

rawProcessor->unpack_thumb() does return LIBRAW_SUCCESS.

Despite getting LIBRAW_THUMBNAIL_UNKNOWN, I go ahead and treat it as LIBRAW_THUMBNAIL_JPEG and I was able to get the thumbnail (preview image) successfully.

I thought those newer cameras are supported in the master branch, so why am I still get LIBRAW_THUMBNAIL_UNKNOWN return code?

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Pink/purple color cast on Sony A7III ARW file?

Submitted by Kuro on

I'm using LibRaw 0.19.2.

I've this pink/purple color cast issue on just one ARW file taken with the Sony A7III. All the other files from the same camera so far looked fine.

But when I open this problematic file with FastRawViewer or other RAW converters, the colors look fine.

So why am I getting this color cast on this one file?

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