Save RAW files in DNG format instead of RAW

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #30 on: 18 / April / 2008, 17:36:37 »
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    « Last Edit: 22 / April / 2008, 18:10:00 by Barney Fife »
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    Offline mkmenuts

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #31 on: 18 / May / 2008, 08:30:42 »
    If the DNG format supports an uncompressed format identical to CHDK RAW (direct from sensor, 10 bit per pixel, no padding) then a useful first step would be to support that:

    1. Produce a DNG header for the RAW with the EXIF data in there
    2. Change the extension to DNG.

    While it may be wasteful in space not to use compression, I believe the savings it time (to not need DNG4PS2 anymore) are there. The size increase should be minimal.

    Also, it would mean direct card to backup is easy and will guarantee the files will be usable years from now (and they may include the right color profile per-camera, as well as other specific info).

    If anyone could point me to the file specification (not the Adobe SDK), I will try to do this, with no compression as a first step.

    A question though, will changing the extension to DNG prevent the camera from identifying the RAW and deleting it with the JPG?

    mkmenuts

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    Offline DataGhost

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #32 on: 18 / May / 2008, 16:32:26 »
    I've been toying with this idea as well, though I didn't get past reading the first few pages of the spec (http://www.adobe.com/products/dng/pdfs/dng_spec.pdf), which might also be the file you want to read.

    Changing the extension to DNG will most likely prevent the camera from identifying it as a RAW file, yes, though it's fairly easy to add that extension to the code if this feature makes it into trunk.

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    Offline ewavr

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #33 on: 12 / November / 2008, 21:35:44 »
    Well, if someone is interesting, test versions with online DNG creation for some cameras are here.

    To increase the speed were made as follows:
     - no compression,
     - RAW buffer caching (optional) - see sRaw .
     - prepared on PC list of all CCD bad pixels (I don't know how read it directly from camera)

    To turn on DNG shooting, turn on RAW and "DNG format" in RAW options. Also you can try to turn on "RAW buffer cached" option.

    List of all CCD bad pixels (CHDK/badpixel.bin) is required for DNG shooting. To generate this list on PC, use show_bad_b tool.
    usage : show_bad_b.exe CHDK_RAW_FILE_NAME
    It creates in current folder output file badpixel.bin and reports about defect pixel count. Try several RAW files to obtain stable result (approximate shooting conditions: minimal ISO, exposure time ~1/10s). Some cameras have two defect pixel lists, which are switched at exposure time ~1/25 s (my cam has 7473 and 3607 defect pixels in each list). Use list with maximum (but stable) defect pixel count, otherwise you can see multiple black points on image in some RAW convertors.

    About DNG and colors: all color profiles are copied from DNG4PS2, nothing new. I am not expert in colors  :'(

    Speed: for 7MP camera and fast 150x SD card DNG creation/saving time is:
    RAW buffer caching is off - 5.4 s
    RAW buffer caching is on - 2.4 s
    Usual CHDK RAW file - 1.0 s

    Not too fast  :'(

    edit: For any camera, supported by DNG4PS2, DNG support can be added.

    edit2: Too many English words for me :)
    « Last Edit: 12 / November / 2008, 21:42:41 by ewavr »


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    Offline lrossel

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #34 on: 13 / November / 2008, 04:05:02 »
    I'll test it right away on my A720IS.
    If you saw me on land, It was just the surface interval
    G10 without CHDK

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    Offline PhyrePhoX

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #35 on: 13 / November / 2008, 04:05:59 »
    \o/
    nice. i gather you also write the exif stuff - do you write the canon values or the chdk (overridden) values?

    hm, no build for the s3is, damn ;)

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    Offline PhyrePhoX

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #36 on: 13 / November / 2008, 05:34:48 »
    applause applause.

    i did a quick test with my s3is (took all the data from a cam with the same sensor, i think a540) and it works like a charm. you can now open the crws directly from the sdcard in photoshop (i guess photoshop notices that these arent real crws but dngs) and edit them directly.

    saving time: about 5.5 seconds for unbuffered, about 2.5 for buffered. yay!

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    Offline wontolla

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #37 on: 13 / November / 2008, 06:35:06 »
    Woha!, it DOES work!

    Lightroom opens the files, generates thumbnails and shows EXIF metadata.

    This is a breakthrough, thanks for the effort ewavr.

    This is a workflow breaker!


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    Offline ewavr

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #38 on: 13 / November / 2008, 06:52:05 »
    i gather you also write the exif stuff - do you write the canon values or the chdk (overridden) values?
    For Av and Tv - overridden values. For ISO - Canon value, but this can be corrected.

    Quote
    hm, no build for the s3is, damn ;)
    No problem, added (also S2, S5, SX100).

    Many thanks to ArtDen and cppasm from russian forum.

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    Offline lrossel

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    Re: Save RAW files in DNG format instead of RAW
    « Reply #39 on: 13 / November / 2008, 07:46:53 »
    If you saw me on land, It was just the surface interval
    G10 without CHDK

     

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