Home > Archive > Compression > June 2004 > Re: How to write 3 symbol alphabets to bit stream?
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Re: How to write 3 symbol alphabets to bit stream?
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| Earl Colby Pottinger 2004-06-24, 6:54 pm |
| budgetanime@mystarship.com (moogie) :
> I have a three symbol alphabet which i would like to convert to a bit
> stream.
>
> The intuitive way of using two bits per symbol would introduce an
> unused 2 bit combination that will unecessarily inflate the bit
> stream.
>
> I am wondering what methods exist to let me use 1.5 bits per symbol?
>
> On average the probabilities of each symbol are: 0.25, 0.375, 0.375.
> In my mind this would equate to bit lengths of 1.248, 0.873, 0.873
>
> I understand Artihmetic Coding uses non integer bits to represent its
> codes. I have been trying to understand how Arithmetic Codes does it
> so i can use/modify its method to my case... however comprehension is
> eluding me :( could someone explain it in more layman terms?
This is a silly question maybe, but did you need a lot of or the max
compression possible? The reason I ask this is, if not a quick hack can
store 5 Tri-value symbols per byte. IE 3^5 = 243 possible values.
Earl Colby Pottinger
--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
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| Michael Schöberl 2004-06-24, 6:54 pm |
| > This is a silly question maybe, but did you need a lot of or the max
> compression possible? The reason I ask this is, if not a quick hack can
> store 5 Tri-value symbols per byte. IE 3^5 = 243 possible values.
8 Bits / 5 Symbols results in 1.6000 Bits/Symbol ... this is
even slightly better than the 1-symbol-huffman :-)
bye,
Michael
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