Support arithmetic encoding and decoding

git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@299 632fc199-4ca6-4c93-a231-07263d6284db

1 files changed, 2 insertions, 12 deletions

diff --git a/README b/README
index ce6e947..2ead09e 100644
--- a/README
+++ b/README
@@ -78,9 +78,8 @@ compressor.)
 This software implements JPEG baseline, extended-sequential, and progressive
 compression processes.  Provision is made for supporting all variants of these
 processes, although some uncommon parameter settings aren't implemented yet.
-For legal reasons, we are not distributing code for the arithmetic-coding
-variants of JPEG; see LEGAL ISSUES.  We have made no provision for supporting
-the hierarchical or lossless processes defined in the standard.
+We have made no provision for supporting the hierarchical or lossless
+processes defined in the standard.
 
 We provide a set of library routines for reading and writing JPEG image files,
 plus two sample applications "cjpeg" and "djpeg", which use the library to
@@ -175,15 +174,6 @@ The same holds for its supporting scripts (config.guess, config.sub,
 ltmain.sh).  Another support script, install-sh, is copyright by X Consortium
 but is also freely distributable.
 
-It appears that the arithmetic coding option of the JPEG spec is covered by
-patents owned by IBM, AT&T, and Mitsubishi.  Hence arithmetic coding cannot
-legally be used without obtaining one or more licenses.  For this reason,
-support for arithmetic coding has been removed from the free JPEG software.
-(Since arithmetic coding provides only a marginal gain over the unpatented
-Huffman mode, it is unlikely that very many implementations will support it.)
-So far as we are aware, there are no patent restrictions on the remaining
-code.
-
 The IJG distribution formerly included code to read and write GIF files.
 To avoid entanglement with the Unisys LZW patent, GIF reading support has
 been removed altogether, and the GIF writer has been simplified to produce