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Save RAW files in DNG format instead of RAW

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Offline ewavr

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Re: Save RAW files in DNG format instead of RAW
« Reply #350 on: 08 / January / 2009, 07:43:01 »
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edit: added (uncommented :D) in trunk.

So, I found that WB settings also present in JPEG EXIF (in maker notes section):

DNG (for reading propertycase #100 values) :
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dng_validate.exe -v DNG_9406.DNG

AsShotNeutral: 0.6039 1.0638 0.6309 (i.e. 1656(=1000/0.6039), 940, 1585 values in properycase #100).

JPEG EXIF (extracted by ShowExif):
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dng_validate.exe -v -d 1024 IMG_9406.THM

Canon MakerNote: Offset = 678, Entries = 24
...<skip>...
*Tag13: 138 entries
...<skip>...
    Long [91] = 940
    Long [92] = 1656
    Long [93] = 1585
    Long [94] = 940

It is a pity that developmant of DNG4PS2 has been stopped  :'(

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Offline PhyrePhoX

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Re: Save RAW files in DNG format instead of RAW
« Reply #351 on: 08 / January / 2009, 08:24:00 »
why do you say that? of course it is a pity, but with dng in chdk it isnt needed anymore (except for new cams to calculate color matrix)? no?

btw in ida you can find strings like colormatrix. shouldnt it be possible to get the colormatrix out of the binary?
« Last Edit: 08 / January / 2009, 09:15:33 by PhyrePhoX »

Re: Save RAW files in DNG format instead of RAW
« Reply #352 on: 08 / January / 2009, 12:09:38 »
Compared to JPEGs, the colors are not exactly the same but they are certainly very close. From this quick test I'd say it works quite perfectly!

Bringing the white balance into the DNG-files is a great improvement for CHDK! (This had to be said in my first posting ever here)

Concerning color differences between JPG and DNG it should be kept in mind, that the camera typically brings some color enhancement into the JPG even in myColors Neutral mode. And it depends on the RAW-converter that is used. For example I have the impression, that RawTherapee gives more saturation into the picture than UFraw. Nevertheless now the way to high quality color management is free and good color profiles for our cameras can be generated.

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Offline fudgey

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Re: Save RAW files in DNG format instead of RAW
« Reply #353 on: 08 / January / 2009, 13:26:58 »
why do you say that? of course it is a pity, but with dng in chdk it isnt needed anymore (except for new cams to calculate color matrix)? no?

Shooting DNG is slower than CHDK CRW raw and requires 10's of kB's of RAM to function. It's more comfortable to use, but that aside it doesn't bring much to CRW+JPEG combination if (now that ewavr heroically found it!) WB would be dug from the JPEG makernotes tab by dng4ps-2.


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Offline PhyrePhoX

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Re: Save RAW files in DNG format instead of RAW
« Reply #354 on: 08 / January / 2009, 13:29:44 »
ok now i get it.
well, the slowness can be overcome when you set quality of the jpg to low. but we still need to find out that hook we can use/call after jpg is written ( https://chdk.kernreaktor.org/mantis/view.php?id=132 )

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Offline fudgey

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Re: Save RAW files in DNG format instead of RAW
« Reply #355 on: 08 / January / 2009, 13:37:20 »
ok now i get it.
well, the slowness can be overcome when you set quality of the jpg to low.

No, that slows things down further unless you have a slow card. Scaling takes more time.

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Offline ewavr

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Re: Save RAW files in DNG format instead of RAW
« Reply #356 on: 08 / January / 2009, 14:48:57 »
well, the slowness can be overcome when you set quality of the jpg to low.

No, because jpeg files are saved in background, raw files - in foreground.

No, that slows things down further unless you have a slow card. Scaling takes more time.
I think that scaling time is near to zero (DSP part of digic is very fast).

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Offline PhyrePhoX

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Re: Save RAW files in DNG format instead of RAW
« Reply #357 on: 08 / January / 2009, 15:01:15 »
hm ok, so this feature wouldnt be useful for speed, but definitly for saving precious cardspace.
btw this background saving, couldnt this be used for the raws as well?
and have you read my post about the temperature (not color :D) tags in exif? how difficult is it to add additional tags? as far as i understood exif, if your favourite image processing software doesnt know an exif tag, it is ignored. so in theory, we could add lots of tags - in theory.


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Offline fudgey

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Re: Save RAW files in DNG format instead of RAW
« Reply #358 on: 08 / January / 2009, 15:08:42 »
I think that scaling time is near to zero (DSP part of digic is very fast).

JPEG continuos mode burst performs fastest in native resolution, slower when scaled down.

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Offline ewavr

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Re: Save RAW files in DNG format instead of RAW
« Reply #359 on: 08 / January / 2009, 15:46:25 »
btw this background saving, couldnt this be used for the raws as well?
I don't know... But RAW files are 1.5-3 times bigger than jpeg with maximal resolution/quality, and RAM buffer for jpeg is not too big (~15 MB for A710, RAW file size ~9MB).
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and have you read my post about the temperature (not color :D) tags in exif? how difficult is it to add additional tags? as far as i understood exif, if your favourite image processing software doesnt know an exif tag, it is ignored. so in theory, we could add lots of tags - in theory.

We discussed this earlier. I don't know in which more or less standard tags this temperature can be stored (UserComment? DeviceSettingDescription? MakerNotes?) and in which form (binary/text). We cannot compel all software developers to read our non-standard tags.
p.s. You can read  EXIF 2.2 standard, all EXIF tags listed on page 30 (printed page number is 24).

« Last Edit: 08 / January / 2009, 15:48:53 by ewavr »

 

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