why are songs encoded in it when you have to convert it to WAV to listen to them or to burn them.

Just interested

that's a damn good question... if people download with broadband anyway then why not just use wav. files?

SHN compresses WAV files to about 60% their original size, in some cases even more.

With the right applications/plug-ins playing and burning them is transparent.

How does that work then?

For that matter does anyone know how zip files work?

They work kinda like this afik,


if you can imagine < kinda a tough one to explain > hmm If you can imagine a Picture of some lovely scenic scene or something to that effect , now thats what you see , ok.


But when the computer looks at it, all it see's is that the picture only uses 5 different colours. So it makes A=Blue , B=Black, C=white etc now it can strip the picture of colour and insert the different letters instead of the colours.


So effectively it now see's AAAACCBBBEEBEDDBDBEBEBDBBEBSBBSBBEBBBSBBDCCCDEDDEE DEDDE


Now what it does is look for paterns in the page for instance, looking at the line I wrote I see the first 4 letters are all A's , so now Ill make the combination of 4 A's in a row =@ <or any other random symbol> looking further along 2 C's in a row, ill make this into # and it continues doing this down the picture


So effectively it will a have a table of values for every combination on the picture, now that might sound more complicated, just looking at the one line of code that i wrote, but if you can imagine 1000000000 pages of it, you will get a picture of how it can save you time


So anyway it builds its table and then it compress's the picture using clever algorithms < that im not going to get into!> so it knows that when you uncompress the picture , it knows where to replace all the differnt elements back to their correct location, so what you see again is the beautifull picture.


That is also why text and will convert alot more that pictures because in text its only black and white , while a picture could have millions of different shades.


And that is a very tired mans explaination of how Zips / compression works. :)

I should have mentioned that I have a degree in computer science, it might have made it easier for you as you woudn't have to come up with an laymans analogy.

So its kinda like how a fax machine works then?

For those that don't know, fax machines don't transmit whether each pixel (not the exact right term I don't think but close enough) is black or white but it transmits how many pixels in succesion are the same colour. so if you have 5 black pixels instead of transmitting 11111 (where 1 signifies a black pixel) you have a code that says "black 5"

Yeah, just give us the code for the algorithm. We'll do just fine [img]smileys/smiley14.gif[/img]

Here's the linear prediction model used by lossless compression.

Actually, FLAC is even better than SHN!

you mean they have the internet on computers now?

oops


Yes, it might have helped a little Ian ;) Sorry if I came across any way condesending or anything it wasnt my attention at all !


It was a late post last night before I went home


Ill just crawl back into my ickle box, close over the lip and roll myself away :)

Ha. I had wondered that myself. I've just read up on the whole Data compression thing, and realised that it's all the stuff i did in college a few years ago, like Huffman and Arithmetic coding.


Why didnt my lecturers present it all w.r.t the compression of audio files etc. Something which im sure the majority of the class would find more interesting.

General archivers like Zip are lossless, too, but they often achieve nearly no compression on audio files. It's basically down the algorithms used.

No problem Adrian, totally my fault.