LibRaw technical support

Stable LibRaw versions: technical support, errors, API questions

Changing parameters without reloading/unpack()

Submitted by Sylvain on

Hi.

I wonder if it is possible to first call:
open_file(...)
unpack()

And then to call several times dcraw_process() -after changing pre_mul for example- without calling recycle(), open_file(...) and unpack() again?

Would memcpying imgdata.image after unpack and back do the trick?

Thanks,

Sylvain.

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About clipping and dcraw_process() stretching to 65535

Submitted by Sylvain on

Hi.

You've already explained that clipping in raw data was difficult to detect (has different forms), and that clipping values may even depend on the color channel.

Imagine a theoretical picture, with, after pre_mul or cam_mul applied, has:
red clipping to 60000.
green clipping to 40000 (I consider g and g2 to have the same behavior).
blue not clipping, climbing up to 50000.

How does dcraw_process() -no_auto_bright=1- stretch this result to 65535?

I guess it can't stretch each channel independently, since this would mess the white balance.

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Determine raw file-type

Submitted by Fimagena on

Hi,

Apologies if I missed something but is there an API-function to determine the file-type of the raw-file opened (and unpacked) with LibRaw?

Specifically, I would like to know if the file represented by the unpacked C++ LibRaw-class is a DNG-file. I can obviously check the filename extension but I'm assuming LibRaw does some internal matching of file types. Is that exposed through the API somewhere?

Many thanks!

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Bayer layout

Submitted by Sylvain on

Hi.

I'm trying to do my own processing: as far as my tests are correct, calling dcraw_process() do the whole job and produces a 8bit image.

I want to get the full bits, so I guess I have to stay with raw2image().
It seems that calling raw2image() gives us a non demozaised image, r, b, and twice g, and that just after a call to raw2image(), the second g cannot be ignored.

Can you confirm that?

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Images processed by libraw are burned/overexposed

Submitted by rav0r on

I own an old Nikon D100 camera and I use both Ufraw and Luminance HDR in order to get simple or HDR photos depending on content. Since Ufraw uses the old dcraw library, it produces a better result while dealing with bright areas. That is funny as they say libraw should be better. I used Darktable as a control app and it produces the same result.

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LibRaw 1.60 in Debian wrong treat PEF from Pentax K-3

Submitted by Mr.Marmaduke on

Hi,

LibRaw 1.60.0 from libraw10 package in Debian Stable (and 1.60.2 in Debian Untable) returns input/output error:

---
egor@shutter:~$ ls -l tmp/raw/
итого 29324
-rw-r--r-- 1 egor egor 30026357 авг 15 15:10 IMGP3859.PEF
egor@shutter:~$ /usr/lib/libraw/simple_dcraw -v -4 -T tmp/raw/IMGP3859.PEF
Processing file tmp/raw/IMGP3859.PEF
tmp/raw/IMGP3859.PEF: data corrupted at 160143
Cannot unpack tmp/raw/IMGP3859.PEF: Input/output error
egor@shutter:~$
---

dcraw (and ufraw, rawtherapee) works fine:

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LibRaw::COLOR or LibRaw::fcol

Submitted by sashab on

HI,

What is recommended way to detect color component of the pixel? Documentation points to COLOR function for this purpose, but as far as I understand it does not always work (e.g. FUJI XTRANS sensors). There is fcol function that is used everywhere in LibRaw internally, but it has somewhat different implementation that COLOR for bayer case. What to use?

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Command Line

Submitted by brancusi on

Hello,

Our project currently uses dcraw. We are having several issues and recently came across LibRaw.

Could you explain how we could transition to LibRaw while using the command line?

This will be running on an ARM distro of linux.

The app is actually running on a Raspberry PI within a dockerized node app. We are looking to grab the thumbnail, and then process the raw image with an applied color profile.

Any guidance in how to set this up would be greatly appreciated.

Thank you!

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