Getting DCT Coefficients from JPEG File using Java ?

Discussion in 'Java' started by Jackson, Dec 2, 2004.

  1. Jackson

    Jackson Guest

    I'm currently doing some development in Java and I need to be able to
    extract the DCT Coefficients from a JPG file.

    I've done some research and found that Java does include a JPEG Decoder
    (com.sun.image.codec.jpeg.*), but I'm not sure how I could leverage
    this to grab the DCT Coefficients.

    It is my understanding that I would have to first, for each 8x8 block,
    decode the huffman values, decode the RLE values, decode the DPCM
    values, and undo zig-zag coding. I'm just not sure how I could get
    this concept into my Java program.

    Jackson, Dec 2, 2004
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  2. Jackson


    Feb 12, 2016
    Likes Received:
    It seems that 11 years later, there is still no simple answer to this. The only solution I found was to use JNA to draw the coefficients using the native JPEG library. My code is very crude but can be easily extended. Here:
    markos, Feb 12, 2016
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