Hi - I need a hint.... I''m just now writing a mpeg-1 layer III decoder/player and I have some troubles/problems. As part of this decoder I need to unpack a huffman code, no problem ?!? well, I''ve created the huffman algoritm, and now, all I need is a huffman tree.... oops, no tree - I''ve looked at some open source stuff and other source code, they seem to have a tree in matrices within a file and I don''t want to copy these since that would - argh - be piracy I guess... so here''s my question, Does anyone know if I can calculate the tree on the fly, any good resources about this ? - or do you have any ideas on how to implement it ? also - I''m, thinking of writing a tutorial about the subject as my work progress, is anyone intrested ?

hmm.. It''s awfully lonely here...
so I guess I''ll just crawl down into the hole I came from and never bother anyone again....
sniffle....

I think those trees MAY be part of the standard, so if you want to do MP3 decoding, you may HAVE to(I know that certain quantization matrices and the ilk are part the JPEG2000 standard). But I haven''t looked that deeply into the standard. Also, beware of Patents, I think some dorks have patents on key pieces of the MP3 technology, irregardless of how you implement it(since the stuff built-in to the standard).

If you get it working, write a tutorial, but I sincerely doubt most people would understand enough of the DSP stuff(unless you''re a brilliant writer). I''m a fan of the roll-your-own-style, take the ideas of the system(sub band coding, quantization, and perceptual encoding to crank the entropy way down, then use a simple huffman code to compress whats left).

YEP, your right...
I found some out that there seems to be a ''standard'' huffman table/tree....
I guess I''ll have to look into the patent stuff...
And yes, a tutorial would be a little difficult to write.
Thanks for the reply.

this is what I was looking for....
If anyone wants to code a mpeg-1 layer III decoder - THIS IS WHAT YOU NEED....
some docs - there''s one specifying the mpeg layer II bitstream....
http://www.mp3-tech.org/programmer/docs/


Now I''m happy again