Can't use CRW files

uhoh

14

Can't use CRW files

« on: 07 / March / 2017, 20:46:19 »

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Hi all,
I forgot to enable DNG mode, so my raw files are in the CRW format, which macOS does not understand. I compiled DCRAW and it too cannot understand these CRW files. I also tried the decompress.c program on Dave Coffin's website but it as well cannot understand these CRW's. My camera is an ELPH 110.
Any suggestions?
Thanks.
Here is the file:
https://www.dropbox.com/s/93ew7b8sdc8zkmz/CRW_2435.CRW?dl=0

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reyalp

13879

Re: Can't use CRW files

« Reply #1 on: 07 / March / 2017, 22:04:12 »

The "CRW" files are not in any real format, they are just a dump of the camera sensor, so any program that supports them needs updated parameters for each new sensor size. That's why we recommend and default to DNG these days.

You could add a profile for your camera in DNG4PS-2, see
https://chdk.setepontos.com/index.php?topic=6754.0

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uhoh

14

Re: Can't use CRW files

« Reply #2 on: 08 / March / 2017, 10:41:51 »

Quote from: reyalp on 07 / March / 2017, 22:04:12

The "CRW" files are not in any real format, they are just a dump of the camera sensor, so any program that supports them needs updated parameters for each new sensor size. That's why we recommend and default to DNG these days.
You could add a profile for your camera in DNG4PS-2, see
https://chdk.setepontos.com/index.php?topic=6754.0

But it also appears to be compressed somehow because there's 1.58 bytes per RGBG subpixel set.
If it weren't compressed I'd just write a C program to do a demosaic operation and write out a BMP.

BTW DNG4PS-2 doesn't build on the Mac.

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waterwingz

12132

Re: Can't use CRW files

« Reply #3 on: 08 / March / 2017, 14:10:46 »

Quote from: uhoh on 08 / March / 2017, 10:41:51

But it also appears to be compressed somehow because there's 1.58 bytes per RGBG subpixel set. If it weren't compressed I'd just write a C program to do a demosaic operation and write out a BMP.

You might find this interesting : How pixel values are stored in CHDK raw?

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Ported : A1200 SD940 G10 Powershot N G16

reyalp

13879

Re: Can't use CRW files

« Reply #4 on: 08 / March / 2017, 16:03:33 »

Quote from: uhoh on 08 / March / 2017, 10:41:51

If it weren't compressed I'd just write a C program to do a demosaic operation and write out a BMP.

It's packed 12 bpp little endian. The rawconvert tool in the chdk source has code to convert this into something easier to work with https://app.assembla.com/spaces/chdk/subversion/source/HEAD/trunk/tools/rawconvert.c

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uhoh

14

Re: Can't use CRW files

« Reply #5 on: 08 / March / 2017, 17:54:45 »

Quote from: reyalp on 08 / March / 2017, 16:03:33

https://app.assembla.com/spaces/chdk/subversion/source/HEAD/trunk/tools/rawconvert.c

Hmm... In the case of my camera, the ELPH 110HS,
http://chdk.wikia.com/wiki/ELPH110HS
I thought the resolution is 4608x3456 = 15925248 pixels.
The CRW file is 25230816 bytes.
25230816 / 15925248 = 1.5843, or roughly 16-to-10.

So if I assume it's a 16-to-10 conversion...
I shouldn't be getting this error from rawconvert... right?

./rawconvert -16to10 -w=4608 -h=3456 -pgm CRW_2435.CRW IMG_2435.PGM
WARNING: Portable Gray Map (PGM) format supports only 8 or 16 bpp.
./rawconvert: CRW_2435.CRW mismatched size (4608*3456*16)/8 -> 31850496 != 25230816

./rawconvert -16to10 -w=4608 -h=3456 CRW_2435.CRW IMG_2435
./rawconvert: CRW_2435.CRW mismatched size (4608*3456*16)/8 -> 31850496 != 25230816

But OK let's try 12 to 8:

./rawconvert -12to8 -w=4608 -h=3456 CRW_2435.CRW IMG_2435
./rawconvert: CRW_2435.CRW mismatched size (4608*3456*12)/8 -> 23887872 != 25230816

10 to 8?

./rawconvert -10to8 -w=4608 -h=3456 CRW_2435.CRW IMG_2435
./rawconvert: CRW_2435.CRW mismatched size (4608*3456*10)/8 -> 19906560 != 25230816

Oh well.

« Last Edit: 08 / March / 2017, 18:05:08 by uhoh »

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srsa_4c

4451

Re: Can't use CRW files

« Reply #6 on: 08 / March / 2017, 20:31:06 »

From the source

Code: [Select]

    #define CAM_RAW_ROWPIX                      4784 // Found @0xff15d2f8 ixus125 100d
    #define CAM_RAW_ROWS                        3516 // Found @0xff15d304 ixus125 100d

Also, bit depth is definitely 12 bits per pixel.

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waterwingz

12132

Re: Can't use CRW files

« Reply #7 on: 08 / March / 2017, 20:37:09 »

Quote from: srsa_4c on 08 / March / 2017, 20:31:06

From the source
Code: [Select]
#define CAM_RAW_ROWPIX 4784 // Found @0xff15d2f8 ixus125 100d #define CAM_RAW_ROWS 3516 // Found @0xff15d304 ixus125 100dAlso, bit depth is definitely 12 bits per pixel.

The OP's row/column data is for the JPEG for that camera.

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Ported : A1200 SD940 G10 Powershot N G16

uhoh

14

Re: Can't use CRW files

« Reply #8 on: 08 / March / 2017, 23:58:35 »

Quote from: srsa_4c on 08 / March / 2017, 20:31:06

From the source
Code: [Select]
#define CAM_RAW_ROWPIX 4784 // Found @0xff15d2f8 ixus125 100d #define CAM_RAW_ROWS 3516 // Found @0xff15d304 ixus125 100dAlso, bit depth is definitely 12 bits per pixel.

./rawconvert -12to8 -w=4784 -h=3516 -pgm CRW_2435.CRW IMG_2435.pgm
input: CRW_2435.CRW 4784x3516 12 bpp 25230816 bytes
output: IMG_2435.pgm 8 bpp 16820544 bytes
discard lower 4 bits
done

I converted all of my CRWs to pgm and they're all random-looking messes. Sometimes my camera puts out jibberish DNGs as well when the shooting mode isn't what it wants. But they usually look a bit different than these.

« Last Edit: 09 / March / 2017, 00:07:12 by uhoh »

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reyalp

13879

Re: Can't use CRW files

« Reply #9 on: 09 / March / 2017, 02:14:38 »

Quote from: uhoh on 08 / March / 2017, 23:58:35

I converted all of my CRWs to pgm and they're all random-looking messes. Sometimes my camera puts out jibberish DNGs as well when the shooting mode isn't what it wants. But they usually look a bit different than these.

If you can upload an example of one of the original CRW files somewhere (dropbox, google drive etc), we may be able to get a better idea of what's happening.

Note that rawconvert does not demosiac, it just takes the packed 12 bit data and converts it 8 or 16 bit formats that can be loaded into other imaging programs. If you load the resulting pgm in gimp or similar, you will generally a recognizable grayscale image with a checkerboard pattern from the CFA.

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