Dictionary Based Coding  -  LZW

1.      Answer

a.      In LZW compression, given that you will never exceed more than 256 codes. How many bits would it take to represent a symbol and how many bits for a code.

b.      Is LZW adaptive? (Give your reasoning)

2.      Answer

a.      What is the main distinction of dictionary based coding (as opposed to compression mechanisms based on statistical models)?

b.      In LZW coding, how is the dictionary initialized?  (What are the initial contents of the dictionary?)

3.      Answer true or false

a.      In LZW, the codes form indexes into a phrase dictionary.

b.      GIF uses Adaptive Huffman compression.

c.      Original LZW implementation used a dictionary with 4096 entries.

d.      In LZW coding, the sender transmits the dictionary along with the sequence of symbols and codes.