Quote:
Originally Posted by DMcCunney
As mentioned, it resulted in the PNG format, and it's a moot point now -- as far as I know, Unisys's rights have expired.
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Yup, since 2003 in the US and since 2004 in most of the rest of the world.
Quote:
Originally Posted by DMcCunney
If it is covered by patent, that will be discoverable. I doubt it, though. I suspect this is "trade secret" -- they just don't tell anyone what they did and how they did it.
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The latter would be ideal for someone trying to reverse-engineer the algorithm, say, through chosen plain-text attacks or something similar. And yes, if there is a patent, it should theoretically be discoverable.
Also, Harry, it may be Huffman, but their claims lead me to believe that they made changes to the compression algorithm so they can start decompressing anywhere they need so they can start presenting page 500 in a book without having to decode all previous pages.
Those changes may very well be patented.