MULTIMEDIA AND QUALITY OF SERVICE
COMPRESSION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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LZ78 has ____ compression but very ____ decompression.
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fast, slow
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slow, fast
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None of these
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None of the above
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Explanation:
Detailed explanation-1: -LZ78, like LZ77, has slow compression but very fast decompression. LZ78 is faster than LZ77 but doesn’t always achieve as high a compression ratio as LZ77.
Detailed explanation-2: -The compression algorithm searches the window for the longest match with the beginning of the lookahead buffer and then outputs a pointer to that match. Because even a 1-byte match might not be found, the output cannot only contain pointers.
Detailed explanation-3: -LZW is a simple variant of LZ78: when a code is output, instead of then outputting the code for the next single character in the input, it uses the next character as the beginning of a new character sequence.
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