ckc@dciem.dciem.dnd.ca (Raymond Cheang) (02/23/90)
Hi! Can someone give me some references on huffman encoding scheme. Is there any PD examples available? Thanks in advance.
justus@tko-sony-22.hut.fi (Juhana R{s{nen) (02/26/90)
In article <2941@dciem.dciem.dnd.ca> ckc@dretor (Raymond Cheang) writes: > >Hi! Can someone give me some references on huffman encoding scheme. >Is there any PD examples available? (1) Abelson & Sussman: Structure and Interpretation of Computer Programs, MIT Press 1985 Contains some basic theory of Huffman encoding and an implementation in scheme (a dialect of lisp :-)); pp. 118-125. But this is a mere example of data abstractions in scheme, more detailed information can be found in (2) Richard Hamming: Coding and information theory (1980) I haven't read this myself, but (1) had a reference to this, and said that (2) should contain discussion of the mathematical properties of Huffman codes. Juhana R{s{nen / justus@niksula.hut.fi
doug@xdos.UUCP (Doug Merritt) (02/28/90)
In article <1990Feb26.112044.17219@santra.uucp> justus@niksula.hut.fi (Juhana R{s{nen) writes: >In article <2941@dciem.dciem.dnd.ca> ckc@dretor (Raymond Cheang) writes: >> >>Hi! Can someone give me some references on huffman encoding scheme. > >(1) Abelson & Sussman: Structure and Interpretation of Computer Programs, > > Contains some basic theory of Huffman encoding and an implementation in > scheme (a dialect of lisp :-)); pp. 118-125. But this is a mere example > >(2) Richard Hamming: Coding and information theory (1980) This is likely to be *quite* mathematical in nature, and hence likely to be close to useless for somebody who just wants to get the job done. Not intended as a flame to Juhana, it's a good reference; just a warning to Raymond. More directly useful might be something like the superb book "Algorithms", by Robert Sedgewick (*everyone* should have this book; it's far more approachable than Knuth. Well, ok, everybody should have Knuth, too). Anyway, it has a short chapter on "file compression", that is 80% a discussion of Huffman encoding, with short example code in Pascal. On a related subject, note that the usually more efficient Lempel Zev encoding is available in the P.D. "compress" program. Doug -- Doug Merritt {pyramid,apple}!xdos!doug Member, Crusaders for a Better Tomorrow Professional Wildeyed Visionary
robert@trwind.UUCP (Robert W. Snyder) (02/28/90)
Robert Snyder > >Hi! Can someone give me some references on huffman encoding scheme. >Is there any PD examples available? > >Thanks in advance. Check out Data Structure Techniques by Thomas A. Standish. Published by Addison Wesley 1980. You might also combine this technique with Karlgrens's representation also described in the book, if you are compressing text. It should increase the ammount of compression you get. The algorithm is very simple, if you dont have trouble with binary trees. Hope this helps -- Robert Snyder Disclaimer -- nobody claims dis, but me TRW Information Networks Division 23800 Hawthorne Blvd, Torrance CA 90505 USENET: trwind!robert INTERNET: robert@trwind.TRW.COM Phone 213-373-9161