LibRaw technical support

Stable LibRaw versions: technical support, errors, API questions

Image Orientation (EXIF)

Submitted by lrusr19 on

Hello,

I'm using LibRaw to process RAW files on Windows. I'm using the March Snapshot built with Visual Studio 2017, 64-bit,

I'm having problems with EXIF orientation in several RAW files, mostly Canon CR2 files.
When the user enables the option to use the embedded preview in the CR2, my software uses the routines

unpack_thumb
dcraw_make_mem_thumb

to create an in-memory image and then I load that image into my image library for further processing. After loading the image my code checks the

imgdata.sizes.flip

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Processing image From Fujitsu X-T3

Submitted by David Partridge on

I've got a two problems with the processing of an image from a Fuji X-T3.

1. It has a black border on the right hand side.

2. It takes about 40 seconds to process using: dcraw_emu -t 0 -4 -j -v -v "DSCF3954(X-Trans).RAF" which I think does three pass interpolation. By huge contrast Adobe Camera Raw 11.3 takes about two seconds even though the image is clearly interpolated (and quite well).

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White balance scaling and values in pre_mul array

Submitted by David Partridge on

I'm doing white balance scaling on the raw data I've retrieved based on the values in imgdata.color.pre_mul

Processing data from a Pentax K-5 I'm seeing the following in pre_mul after calling unpack():

White balance co-efficients being used are 2.155461, 0.926686, 1.305787, 0.000000

I'm slightly surprised to see that a) the second value isn't 1.0, and b) that the fourth value is zero.

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Fujitsu Super-CCD files not processed "correctly"

Submitted by David Partridge on

A Fujitsu RAF file from a Super-CCD sensor camera contains two images. One has the data from the larger more sensitive "S" sensels, the other for the smaller, less sensitive "R" sensels. These are supposed to be HDR combined while processing the file. Please refer to the discussion at https://translate.google.ie/translate?sl=auto&tl=en&u=http%3A%2F%2Fwww.g... for an overview of this.

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Processing Fuji raw_image

Submitted by David Partridge on

By code to process the raw_image array looks like this:

#define RAW(row,col) \
	RawData.raw_image[(row)*S.raw_width+(col)]
 
for (row = 0; row < S.height; row++)
{
	for (col = 0; col < S.width; col++)
	{
           unsigned short val = 
              RAW(row + S.top_margin, col + S.left_margin);
           // etc ...
        }
}

This works very well for Canon raw images, but totally falls apart when processing a Fuji RAF file from an S5-Pro.

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color.maximum and camera white level

Submitted by David Partridge on

Is the value in color.maximum the camera white level ("full well" or saturation value)? If so I am a bit confused as the data I'm testing with appears to contain pixel values that are greater than color.maximum (after subtraction of dark level).

To be more specific I'm using a CR2 file from a Canon EOS 60Da where color.maximum is showing up as 12279 but the largest pixel value in raw_image (ignoring the frame) is 13259 (after subtraction of dark value of 2047).

If color.maximum isn't the white level, is the white level for the camera available in libraw?

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