[ros-dev] Re: [ros-svn] [mbosma] 20952: Delete libjpeg because
greatlord thought we should wait with jpeg support until the patent expired.
If someone got a different opinion please take the issue to ros-dev.
mf at mufunyo.net
Fri Jan 20 20:59:40 CET 2006
art yerkes wrote:
> There's a lot of FUD going on here.
I agree wholeheartedly.
> For one thing, our SEH method is not patented.
For another thing, the patent appears to be this:
The JPEG spec defines two different "back end" modules for the final
output of compressed data: either Huffman coding or arithmetic coding is
allowed. The choice has no impact on image quality, but arithmetic
coding usually produces a smaller compressed file. On typical images,
arithmetic coding produces a file 5 to 10 percent smaller than Huffman
coding. (All the file-size numbers previously cited are for Huffman
Unfortunately, the particular variant of arithmetic coding specified by
the JPEG standard is subject to patents owned by IBM, AT&T, and
Mitsubishi. Thus *you cannot legally use JPEG arithmetic coding* unless
you obtain licenses from these companies. (Patent law's "experimental
use" exception allows people to test a patented method in the context of
scientific research, but any commercial or routine personal use is
I recommend that people not use JPEG arithmetic coding; the space
savings isn't great enough to justify the potential legal hassles. In
particular, arithmetic coding *should not* be used for any images to be
exchanged on the Internet. Even if you don't care about US patent law,
other folks do.
I believe that something like that is easily commented out, and does not
require a removal of the entire lib. *sings the FUD song*
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