DATA CODING
Briefly, in accordance with one embodiment, a method of coding data is described.
1 . A method of coding an alphabet of N symbols for storage and/or transmission by a computing platform, the alphabet of N symbols ranked by expected probability of occurrence, the method comprising:
assigning a threshold probability T;
coding symbols which have a higher probability of occurrence than the threshold probability T with a variable length code; and
coding symbols which have a probability of occurrence substantially the same as or lower than the threshold probability with a fixed length code.
2 . The method of claim 1 , wherein the variable length code comprises a Huffman code.
3 . The method of claim 1 , wherein the fixed length code comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probably T, followed by, a second code which uniquely identifies a given symbol from the threshold probability T and from any other symbol having a probability of occurrence lower than the threshold probability T.
4 . The method of claim 1 , wherein the coding comprises binary coding.
5 . The method of claim 4 , wherein the fixed length code comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probability T, followed by, a second code indicative of a binary representation of a numeral in the range 1 to N−T.
6 . The method of claim 5 , wherein the first code comprises a sequence of zeros and/or ones.
7 . The method of claim 6 , wherein N−T+1 is chosen to be a power of two.
8 . The method of claim 1 , for coding a stream of binary data, wherein the symbols are represented by a series of bits.
9 . The method of claim 1 , wherein the symbols are represented using a length of a run.
10 . A storage medium having stored thereon instructions that, if executed by a computing platform, result in performance of a method of coding an alphabet of N symbols for storage and/or transmission by the computing platform, the alphabet of N symbols ranked by expected probability of occurrence, the method comprising:
assigning a threshold probability T;
coding symbols which have a higher probability of occurrence than the threshold probability T with a variable length code; and
coding symbols which have a probability of occurrence substantially the same as threshold probability or lower with a fixed length code.
11 . The storage medium of claim 10 , wherein said instructions, if executed, further result in the variable length code comprising a Huffman code.
12 . The storage medium of claim 10 , wherein said instructions, if executed, further result in the fixed length code comprising: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probably T, followed by, a second code which uniquely identifies a given symbol from the threshold probability T and from any other symbol having a probability of occurrence lower than the threshold probability T.
13 . The storage medium of claim 10 , wherein said instructions, if executed, further result in the coding comprising binary coding.
14 . The storage medium of claim 13 , wherein said instructions, if executed, further result in the fixed length code comprising: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probability T, followed by, a second code indicative of a binary representation of a numeral in the range 1 to N−T.
15 . The storage medium of claim 14 , wherein said instructions, if executed, further result in the first code comprising a sequence of zeros and/or ones.
16 . The storage medium of claim 15 , wherein said instructions, if executed, further result in N−T+1 being chosen to be a power of two.
17 . The storage medium of claim 10 , wherein said instructions, if executed, further result in, for coding a stream of binary data, the symbols being represented by a series of bits.
18 . The storage medium of claim 10 , wherein said instructions, if executed, further result in the symbols being represented using a length of a run.
19 . An apparatus comprising:
means, for an alphabet of N symbols ranked by expected probability of occurrence, for assigning a threshold probability T;
means for coding symbols which have a higher probability of occurrence than the threshold probability T with a variable length code; and
means for coding symbols which have a probability of occurrence substantially the same as threshold probability or lower with a fixed length code.
20 . The apparatus of claim 19 , wherein, said means for coding symbols with a variable length code comprises means for coding symbols with a Huffman code.
21 . The apparatus of claim 19 , wherein the fixed length code to be coded comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probably T, followed by, a second code which uniquely identifies a given symbol from the threshold probability T and from any other symbol having a probability of occurrence lower than the threshold probability T.
22 . The apparatus of claim 19 , wherein the coding comprises binary coding.
23 . The apparatus of claim 22 , wherein the fixed length code to be coded comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probability T, followed by, a second code indicative of a binary representation of a numeral in the range 1 to N−T.
24 . The apparatus of claim 23 , wherein the first code to be coded comprises a sequence of zeros and/or ones.
25 . The apparatus of claim 24 , wherein N−T+1 is to be chosen to be a power of two.
26 . The apparatus of claim 19 , for coding a stream of binary data, wherein the symbols are to be represented by a series of bits.
27 . The apparatus of claim 19 , wherein the symbols are represented using a length of a run.
28 . A computer platform configured to code an alphabet of N symbols for storage and/or transmission by said platform, said platform adapted to: for an alphabet of N symbols ranked by expected probability of occurrence, assign a threshold probability T, code symbols which have a higher probability of occurrence than the threshold probability T with a variable length code, and code symbols which have a probability of occurrence substantially the same as threshold probability or lower with a fixed length code.
29 . The computer platform of claim 28 , the variable length code comprises a Huffman code.
30 . The computer platform of claim 28 , wherein the fixed length code comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probably T, followed by, a second code which uniquely identifies a given symbol from the threshold probability T and from any other symbol having a probability of occurrence lower than the threshold probability T.
31 . The computer platform of claim 28 , wherein said computing platform is further adapted to code symbols using binary coding.
32 . The computer platform of claim 31 , wherein the fixed length code comprises: a first code which differs from any possible code for a symbol having a higher probability of occurrence than the threshold probability T, followed by, a second code indicative of a binary representation of a numeral in the range 1 to N−T.
33 . The computer platform of claim 32 , wherein the first code comprises a sequence of zeros and/or ones.
34 . The computer platform of claim 33 , wherein a value of N−T+1 is chosen to be a power of two.
35 . The computer platform of claim 28 , wherein said computing platform is further adapted, for coding a stream of binary data, so that the symbols are represented by a series of bits.
36 . The computer platform of claim 28 , wherein said computing platform is further adapted so that the symbols are represented using a length of a run.