Subject: Re: [Q] Lossless JPEG

From: [email-masked] ( Achille Hui, the Day Dreamer )
Date: 06 Jun 94 21:51:10 GMT

[email-masked]
|
| Hello,
|  
| I am currently researching JPEG compression techniques. In particular
| I am interested in Lossless JPEG compression. Unfortunately the FAQ of
| this BB dosen't mention much about it. I would appreciate any leads,
| ftp sites, currrent state of art in lossless JPEG.
| 
The best reference is the book "JPEG still image data compression standard"
by William B. Pennebaker and Joan L. Mitchell published by Van Nostrand
Reinhold (ISBN 0-442-01272-1). It also include the relevant ISO DIS documents
as appendices. The only public domain code which can deal with lossless JPEG
is the PVRG code from Stanford (available through ftp at havefun.stanford.edu)
Unluckily, it only handles the Huffman encoding mode (Unlike lossy JPEG,
the compression model used in arithmetic encoding mode for lossless JPEG is
different from those used in the Huffman encoding and offer much superior
compression ratio) and is horribly slow. I would suggest you to grab the
aforementioned book and code the arithmetic mode yourself. (At least for the
lossless JPEG part, the coding is amazing simple).

Hope this helps...
---------------------------------------achille ([email-masked])