Better JPEG program - minimized JPEG degredation

Discussion in 'Digital Cameras' started by Paul D. Sullivan, Jan 26, 2007.

  1. I was following the discussion and started doing some searching.

    I found this app called Better JPEG that says it does some key
    operations in a method that absolutley minimizes recompression.

    http://www.betterjpeg.com/

    Has anyone heard about this? It seems a smart way to do things,
    but I'm not sure if it is BS or if it is real.

    If you have any experience on this app, please share some
    feedback if you would.

    Thanks
     
    Paul D. Sullivan, Jan 26, 2007
    #1
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  2. With the right software, you can perform cropping and 90-degree step
    rotations on JPEG images /without/ incurring any extra loss due to
    re-compression. E.g. Jpegcrop:

    http://sylvana.net/jpegcrop/

    David
     
    David J Taylor, Jan 26, 2007
    #2
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  3. Paul D. Sullivan

    Mike Fields Guest

    "David J Taylor"
    Irfanview (FREE) also supports "lossless" jpg rotations.

    mikey
     
    Mike Fields, Jan 26, 2007
    #3
  4. Paul D. Sullivan

    HEMI-Powered Guest

    Today, David J Taylor made these interesting comments ...
    adept cropping and 90 deg rotates can indeed result with no image
    degradation but how does one then save the image without incurring
    at least some loss, unless you've figured out an algorithm for
    altering the compression factor, chroma subsampling, etc. that
    minimizes damage? I've always been taught that as soon as you re-
    save at least some damage is done, but NOT necessarily enough to be
    concerned about or to even see
     
    HEMI-Powered, Jan 27, 2007
    #4
  5. I was impressed by their language on their site in way of
    explanation. They say they optimize it so only the actual pixels
    that have changed are re-saved. It does not process any other
    blocks of pixels. Sounds quite smart.

    I think I'm going to try that program out more in-depth. Red Eye
    Reduction with almost no hit in quality sounds quite good indeed.
     
    Paul D. Sullivan, Jan 27, 2007
    #5
  6. Paul D. Sullivan

    HEMI-Powered Guest

    Today, Paul D. Sullivan made these interesting comments ...
    Can't comment on a specific program which may have been written
    to minimize image damage under certain well-defined situations as
    I haven't tried it/them. I was talking in general terms using my
    knowledge - or lack thereof - of who the JPEG spec was designed
    and how it is implemented in software.

    For me, I try never to re-edit the same image, if I can, I will
    go back to the original unedited camera image which I always
    save. However, both the 80/20 Rule and the Law of Diminishing
    Returns get in the way of that rigid a rule, so I do re-edit my
    own or others images. However, I carefully examine the image to
    see what damage is already there - it may be slight or
    considerable - and usually go to a lower compression rate and/or
    alter chroma sub-sampling to achieve best possible results.

    Depending on the types of damage I may see, such as jaggies,
    posterization, artefacts, noise, etc. etc., I may apply mild-to-
    agresssive corrective action before re-saving. But, one thing I
    ALWAYS do, no matter if it is a first-time save or a multiple
    edit/save/edit/save cycle, is immedately open the just saved (or
    re-saved) image an relook for damage. Sometime I see considerable
    damage even on a 1st time save, for which I alter my technique as
    described above.

    Since I am not a pro nor do I print to large sizes, I can afford
    compromizes that others may find to be unacceptable. Thus, unless
    I am specifically saving proprietary items such as layers vector
    data, I usually don't save to a non-compressed format.

    Just one man's opinion, YMMV ...
     
    HEMI-Powered, Jan 27, 2007
    #6
  7. Good points you make. What with data storage being so cheap
    compared to the old days, I can get 7 meg JPG into 14 meg PSP and
    store 'em in that native Paint Shop Pro format without much
    trouble.
     
    Paul D. Sullivan, Jan 27, 2007
    #7
  8. Paul D. Sullivan

    HEMI-Powered Guest

    Today, Paul D. Sullivan made these interesting comments ...
    Since I seldome use vector data or extensive layering, PSPimage
    isn't that important to me, nor have the many advantages of RAW
    been enough to overcome the steep learning curve.

    For your example of a 7 MB JPEG into an 8MB PSP, that seems
    extreme. What pixel size was used in this comparo? When I do
    that, the ratio is more like 10:1 in favor JPEG.
     
    HEMI-Powered, Jan 27, 2007
    #8
  9. HEMI-Powered wrote:
    []
    In programs such as JPEGcrop, although the image is presented to the
    viewer in an uncompressed form for examination and selection of the
    cropping region (i.e. as 24-bit RGB), internally the 8 x 8, or 16 x 16
    blocks comprising the original JPEG are retained, and the rotation or crop
    are made on these blocks, and /not/ on the RGB data.

    So, for example, crop simply consists of writing out only the blocks you
    need, and altering the file headers to reflect the new number of pixels.
    The content of the blocks - the compressed JPEG data - is not altered, so
    no new compression loss is incurred because there is no recompression.

    Lossless rotation (only at 90 degree angles) is achieved by similar
    mathematical operations on the data in the blocks, but again without any
    decompression and re-compression.

    It's a neat idea which works very well.

    David
     
    David J Taylor, Jan 27, 2007
    #9
  10. Since I seldome use vector data or extensive layering, PSPimage
    I use tons of layers, so it's a very convenient format for me.
     
    Paul D. Sullivan, Jan 27, 2007
    #10
  11. Great info! Thanks much.
     
    Paul D. Sullivan, Jan 28, 2007
    #11
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