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Thread: Stuffit 12 beta

  1. #1
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    From www.maximumcompression.com
    Quote Originally Posted by encode
    The tested Stuffit 12.0 is an early beta version, of Stuffit for windows. It includes a lot of changes to the compression code, the most important being recompression techniques for several new file types including MP3 and PDF!. Stuffit 12.0 would take 2nd in both the JPG and BMP test, and 1st in the PDF one (it compresses the file to under 3300 KB!). On the MFC test it shaved of about 3,5 MB compared to version 11.0.

    Thats very good news, but there is one thing to note: Some file types are compressed "pixel perfect", in stead of "bit perfect", in the case of images for example, not a single pixel or ancillary info (headers, tags, etc) is changed or lost in the compression/decompression process, however the decompressed size and/or bit sequence may be slightly different than the original after it has been compressed/decompressed. This is perfectly fine for normal users, but this is a lossless compression test. It would be unfair towards the lossless "bit perfect" compressors to include these Stuffit 12.0 result. Im not sure what to do at the moment. I can retest it after I disable all the recompression tricks (but compression would be worse) or I can add the results but with a note.
    What do you think about it?

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    Hello everyone,

    lossless is lossless!
    It would be fine if Stuffit would give information about that "feature". But afaik it doesn't
    What comes next? Every second pixel in a row vanishes? <uups! But don't bother, now your picture does even fit better on the screen!>
    What happens to pictures that are compressed, decompressed, compressed again,...
    It _has_to_be_clearly_stated_!
    'nuff said

    Best regards!

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    Quote Originally Posted by Vacon
    What happens to pictures that are compressed, decompressed, compressed again,...
    It _has_to_be_clearly_stated_!
    Its not that the image will change... only the file thats holding it

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    but what if i computed for example md5 checksums and then sent them together with archive to a group of friends?

    it should be made an option, like in infima - 'optimize source files'. users should have a choice.

    imo, non bit- perfect archives shouldn't be included in benchmark results or size of difference file should be added.

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    Quote Originally Posted by donkey7
    it should be made an option, like in infima - optimize source files. users should have a choice.
    I was waiting who will say that cursed name first

    Quote Originally Posted by donkey7
    imo, non bit- perfect archives shouldnt be included in benchmark results or size of difference file should be added.
    I definitely agree!

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    Hi,


    I think I'm not up to date with that problem. Was it in earlier StuffIt versions, too?

    If anyone could send me example data (JPEGs, of course; before compression & after recompression), I could research that problem (why/how it happens).

    I think there should be no change, after a JPEG file was recompressed once. If it is done again, there won't be any further change, right?

    Btw. with packJPG it is also possible to test wether the pixel data is really unchanged between two JPEGs, regardless of file structure.

  7. #7
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    Not being "bit perfect" without carefully notifying the user is pretty severe.

    Imagine an image inside a signed PDF. The SHA/MD5 fingerprints would no longer match.

    I'd say Stuffit should be discarded from the test.

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    This is i kind of "feature" that should NOT be enabled as default.

    It should be hidden under some advanced options as the default user should not have to use it.

    Its a walking into a grey zone (meaning probably lsot in transition) to put this into a default mode.

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