LibRaw technical support

Stable LibRaw versions: technical support, errors, API questions

Color Information - Documentation

Submitted by SteveR on

Hi Alex:

In the Structure "libraw_colordata_t: Color Information", there are two arrays:-
float rgb_cam[3][4], described as "Camera to sRGB conversion matrix", and
float cmatrix[3][4], described as "Camera color data read from RAW file (if any)".

Could you advise me on the various properties contained within these arrays, or which source file(s) describes these arrays?

Thanks

Steve

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preserving DNG brightness on conversion to RGB

Submitted by Enedin on

I'm trying to use libRAW to convert some DNG files into a format readable from Matlab.

I take a number of images with specific exposure times and I need the conversion from DNG to any RGB format to preserve the relative luminosity of the images.

If I do the conversion using the Adobe DNG SDK it works well (I use stage 3 of the conversion, before auto-exposure and other processing).

If I use DCraw_emu from the libRAW Windows binaries, I see that the relative brightness of the images is altered.

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libraw_rawdata_t not being populated with C API

Submitted by calandracas on

While working with the C API, I found some behaviour that I think is probably user error (my error) but might be a bug, and if it is my error, I would like to know how to fix it.

Looking at the documentation, after calling libraw_unpack() I expect the libraw_rawdata_t structure to be populated with the raw data.

This is partially what is happening, libraw_rawdata_t.raw_image[] is populated with the raw bayer data, the data in the structure appears to be correct, and I can successfully demosaic it into a proper image.

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Camera Makes and Models

Submitted by SteveR on

Hi Alex

I am working on an astronomy software project in VB.NET accessing LibRaw through a Wrapper from https://github.com/hurlbertvisionlab.
To further test my software, would you be able to give me one example of camera Make and Model that produces output for each these 5 data fields i.e. presumably 5 different Makes/Models:-

unsigned short (*color3_image)[3]
unsigned short (*color4_image)[4]
float *float_image
float (*float3_image)[3]
float (*float4_image)[4]

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Windows platform libraw bring in dng sdk has no effect or can't open dng file

Submitted by cool on

Windows platform libraw bring in dng sdk has no effect or can't open dng file

I compiled dngsdk under Windows as described in dngsdk.txt and tested dng_validate and it works fine
But when I bring the entire dng sdk header file and static library into libraw to compile and set the `USE_DNGSDK ` preprocessing macro, it compiles fine but when I open the dng file with libraw, it tells me that it can't be opened for unsupported file formats. So I would like to ask if I am missing something?

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Compiling Libraw with RawSpeed

Submitted by TomL on

I'm trying to have libraw with rawspeed support (ubuntu 22.04), but I can not manage to make it work.

Here's what I'm doing so far,
I have folder parent/ where I put Libraw-0.20.0 and 'rawpseed-master' renamed to 'RawSpeed'. (I have two folders, parent/LibRaw-0.20.0 and parent/RawSpeed).

For RawSpeed :
-copy/paste the patches from parent/LibRaw-0.20.0/RawSpeed/ to parent/RawSpeed/RawSpeed,

-execute commands :"patch < rawspeed.cpucount-unix.patch", "patch < rawspeed.qmake-pro-files.patch" and then "qmake -makefile rawspeed-lib.pro"

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Comb distribution after PhaseOne image debayering

Submitted by Twz93 on

Hi,

I found a strange problem after analyzing the histograms on images right after debayering (16-bit data so 65536 bins per channel). We use PhaseOne cameras at work and we are interested to get images with a minimum of processing done (debayering, 16-bit per channel, linear response, nothing else). I tried different debayering algorithm using the user_qual but the same problem can be observed. I also created the distribution of the last digit of the pixel values. You can see clearly that there is a unbalance between even and odd numbers. See the attached screenshots.

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Converting ARW’s on Mac OS Leopard

Submitted by Rombay on

I’m still not sure I fully understand what LibRaw even is.

Is this something that executes in command line, or is it just a compatibility add-on for applications that already work with RAW files?

My goal is to simply convert RAW files from a Sony A7 II to something that is natively supported in Mac OS X Leopard 10.5 while still using Leopard.

I know I could do this in another OS but the point is that this is a hub for my workflow for years and I don’t want to lose Aperture support or change my tools just because I got a later camera.

Hardware is Intel x86-64

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Converting ARW’s on Mac OS Leopard

Submitted by Rombay on

I’m still not sure I fully understand what LibRaw even is.

Is this something that executes in command line, or is it just a compatibility add-on for applications that already work with RAW files?

My goal is to simply convert RAW files from a Sony A7 II to something that is natively supported in Mac OS X Leopard 10.5 while still using Leopard.

I know I could do this in another OS but the point is that this is a hub for my workflow for years and I don’t want to lose Aperture support or change my tools just because I got a later camera.

Hardware is Intel x86-64

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