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    #21
    Red Team Graeme_Nattress's Avatar
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    DOn't just take my word for it - do a before and after and diff the results.

    Graeme
    www.nattress.com - Film Effects and Standards Conversion for FCP
    www.red.com - RED - 4k Digital Cinema Camera


     

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    #22
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    There are two types of compression systems in the world, lossy and lossless. Lossy = most video or photo compression systems, such as MPEG or JPG, where the loss in image detail isn't vital. Then there's lossless, typically used for data where the data must be absolutely 100% perfectly restored when uncompressed. LZW and Huffman are examples of lossless compression systems; ZIP employs lossless compression so what you unzip will be 100% identical to what you ZIPped.


     

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    #23
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    Zip is and always has been 100% lossless. Gzip and bzip2 are also lossless. These programs normally don't gain you much for images because there is not much precisely regular structure at the pixel level, as there is with source code or natural language text for example. But even if the compression isn't much it's still handy just to have an image collection archived into a single file.

    I tried ZIP on the RGB_f11 image posted at
    http://www.cinematography.net/red-exposure.html and it wasn't a huge space savings:
    original tiff: 75,861,202 bytes
    ZIP version: 69,523,067 bytes


     

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    #24
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    Quote Originally Posted by jbeale
    Zip is and always has been 100% lossless. Gzip and bzip2 are also lossless. These programs normally don't gain you much for images because there is not much precisely regular structure at the pixel level, as there is with source code or natural language text for example.
    Well, for line art, etc. where there are large areas of single colors, these algorithms do very well, often achieving better compression than they get for natural language text (which is usually a bit over 2:1). For photos, where even areas that are visibly a single color are actually broken up by noise at the pixel level, yeah, they tend not to do so well. PNG, a lossless algorithm actually optimized for images, can cut these files down to ~50 MB.
    Last edited by Chris Kenny; 11-15-2006 at 12:06 PM.


     

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    #25
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    Quote Originally Posted by Graeme_Nattress
    DOn't just take my word for it - do a before and after and diff the results.

    Graeme
    On a separate note, I'm looking forward to doing this with a RAW vs. REDCODE RAW image.


     

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    #26
    Red Leader Jannard's Avatar
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    I'll be stunned if you feel the need to shoot RAW instead of REDCODE after making the comparisons.

    Jim


     

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    #27
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    Quote Originally Posted by Jannard
    I'll be stunned if you feel the need to shoot RAW instead of REDCODE after making the comparisons.

    Jim
    Music to my ears!

    After struggling over another thread talking about what sort of Raid we'll have to set up to shoot raw -- I can't even imagine shooting a feature without a Peter Jackson sized budget and even thinking about shooting RAW.

    Based on what I've seen and what you've just said--I think even Peter Jackson will shoot Redcode!

    Thom


     

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    #28
    Senior Member visceralpsyche's Avatar
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    Quote Originally Posted by jbeale
    I tried ZIP on the RGB_f11 image posted at
    http://www.cinematography.net/red-exposure.html and it wasn't a huge space savings:
    original tiff: 75,861,202 bytes
    ZIP version: 69,523,067 bytes
    Purely for interest I tried 7zip Ultra compression on that same file and got 58.0MB (used 128MB dictionary, LZMA, word size 273). Not all lossless compression schemes are created equal - Graeme can attest to that
    Paul Leeming
    Writer/Director/Cinematographer/Actor
    Visceral Psyche Films
    www.visceralpsyche.com
    www.LeemingLUTPro.com

    Mobile NL: +31 6 2095 2590
    Mobile JP: +81 80 8439 4635
    Facebook: Paul Leeming


     

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    #29
    Red Team Rob Lohman's Avatar
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    It would be around 55 MB just by storing it as a 12-bit TIFF instead of 16-bit. A lot of programs are not able to work with such files though (CS2 for example)
    www.red.com - RED - 4k Digital Cinema Camera


     

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