JPEG 2000 is sloooww...

Discussion in 'Digital Photography' started by Alfred Molon, Apr 6, 2004.

  1. Alfred Molon

    Alfred Molon Guest

    I tried to use JPEG 2000 because it's the only compressed format capable
    of storing 16 bit files, but it appears that the time needed to read and
    write JPEG 2000 images is HUGE. Is anybody else using this file format
    and what (compressed) alternatives exist to store 16 bit images ?
     
    Alfred Molon, Apr 6, 2004
    #1
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  2. Alfred Molon

    John Bean Guest

    TIFF supports 16-bit and many kinds of compression, it's up to the
    application to make use of it.
     
    John Bean, Apr 6, 2004
    #2
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  3. I tried to use JPEG 2000 because it's the only compressed format capable
    Unfortunately you are right 16 bit JP2 pictures do load much slower than 8
    bit JPG. Here some examples using Thumps Plus 20000 on a 1 GHz P3, loading a
    2000*3000 pixel picture:

    16 Bit JP2, file size 1500K : 13 seconds
    16 Bit JP2, file size 49 K : 12 seconds
    8 Bit JP2, file size 1500K : 4 seconds
    8 Bit JP2, file size 120K : 3 seconds
    8 Bit JPG, file size 3000K : 2 seconds



    -Michael
     
    Michael Schnell, Apr 6, 2004
    #3
  4. Yepp - but the compression is not all that impressive.


    /Roland
     
    Roland Karlsson, Apr 6, 2004
    #4
  5. TIFF supports 16-bit and many kinds of compression, it's up to the
    The 16 Bit uncompressed TIFF file is 36 MB and loads in 7 seconds.

    A JP2 of about 1 MB does not look considerably less sharp and does not show
    any artifacts (like JPG would), loads in about the double time and uses just
    1/36 of the disk space.

    -Michael
     
    Michael Schnell, Apr 6, 2004
    #5
  6. Alfred Molon

    John Bean Guest

    The understatement of the year, but at least it's lossless. ZIP gives a bit
    better compression than LZH but it's not well supported other than in
    Photoshop.
     
    John Bean, Apr 6, 2004
    #6
  7. Alfred Molon

    John Bean Guest

    I'm not advocating TIFF, I was just answering the original poster's question
    "what (compressed) alternatives exist to store 16 bit images?"

    As Roland pointed out, TIFF compression is not impressive, but it exists and
    it is an alternative for 16-bit storage.
     
    John Bean, Apr 6, 2004
    #7
  8. Alfred Molon

    Tony Spadaro Guest

    Tony Spadaro, Apr 6, 2004
    #8
  9. PNG supports 16-bit data.

    David
     
    David J Taylor, Apr 7, 2004
    #9
  10. Alfred Molon

    Drifter Guest

    I second the vote for .PNG
    The bottom line is that space/speed are the price you pay for 16 bit
    files. My own workflow consists of saving the RAW files from my
    camera in a sub folder called RAW. These are the "Digital Negatives"
    that doesn't get touched. A second copy (in another folder) gets
    saved as a plain old 8 bit JPG file for common ease of use. If I
    decided I really want to work with an image (usually to prep it for
    printing) then I go back to the "digital negative" and make a .PNG to
    do my editing. I then save that .PNG (loss less compression) for
    printing or later use (probably one file in 100).


    Drifter
    "I've been here, I've been there..."
     
    Drifter, Apr 7, 2004
    #10
  11. Alfred Molon

    Alfred Molon Guest

    My brother is going to scan his slides at 4000 dpi, which gives 20
    MPixel images, which at 16 bit/colour channel gives 120 MB TIFF files.
    It will be necessary to reduce these files to at least 20MB, perhaps
    better 10MB. Can PNG do that, i.e. does it offer so much compression ?
     
    Alfred Molon, Apr 7, 2004
    #11
  12. []
    Any compression level reached is image specific - you would really need to
    test it out in practice. However, the compression algorithm in PNG is
    designed specifically for images, whereas the LZW algorithm used in TIFF
    is not. I would therefore expect smaller files, and that has been
    reported elsewhere in this group.

    Cheers,
    David
     
    David J Taylor, Apr 7, 2004
    #12
  13. Alfred Molon

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    In <SJYcc.5037$> on Wed, 07 Apr 2004
    In my experience, PNG doesn't produce enough space savings over uncompressed
    TIFF (typically less than 25%) to warrant its use. Compressed TIFF (LZW) may
    actually result in larger files. So I just use uncompressed TIFF when I want
    lossless storage.
     
    John Navas, Apr 7, 2004
    #13
  14. Alfred Molon

    JPS Guest

    In message <c4v6i5$8tu$06$-online.com>,
    A 36MB uncompressed 16-bit TIFF loads in less than 1 second here in
    Photoshop CS, from the time I double-click on the filename until it is
    displayed on the screen. It takes 281 milliseconds in irfanview.
    --
     
    JPS, Apr 9, 2004
    #14
  15. Alfred Molon

    JPS Guest

    In message <>,
    Now that I think about it, that irfanview figure should be impossible,
    because my hard disk is only good for about 50 MB/s. It must be
    reporting load time incorrectly (or only reading the high order byte for
    eachpixel-channel, but even that would be too fast).
    --
     
    JPS, Apr 9, 2004
    #15
  16. Alfred Molon

    John Navas Guest

    [POSTED TO rec.photo.digital - REPLY ON USENET PLEASE]

    I doubt it can actually come anywhere close to that speed on real world
    transfers.
     
    John Navas, Apr 9, 2004
    #16
  17. []
    Unless it's the very first time it has loaded, it will most likely be in
    the memory cache (of the hard disk), and you are therefore seeing "load
    from memory" and not "load from disk" times....

    Cheers,
    David
     
    David J Taylor, Apr 9, 2004
    #17
  18. PNG supports 16-bit data.

    In a test picture the png file was 29 MB from a 4.8 MB Nikon D100 RAW.

    -Michael
     
    Michael Schnell, Apr 9, 2004
    #18
  19. The 16 Bit uncompressed TIFF file is 36 MB and loads in 7 seconds.
    With such a fast loading JP2 will be faster, either. I only wanted to point
    out that on the machine here using ThumbsPlus 2000 loading the 16 Bit TIFF
    takes about half the time as loafing the 16 Bit JP2.

    -Michael
     
    Michael Schnell, Apr 9, 2004
    #19
  20. I suspect Irfanview is reporting the CPU time used by Irfanview to
    decode and format the image for display. It probably is not real time,
    nor does it include system overhead. This number is interesting for
    JPEG decoding on slow computers, maybe, but not for much else.

    Dave
     
    Dave Martindale, Apr 9, 2004
    #20
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