what is extended huffman coding.How it can improve the performance of a system?

Question

what is extended huffman coding.How it can improve the performance of a system?

Answer 1

Huffman coding is used to compress written text messages or audio or video signals by reducing the redundancy in the signal. For example English has nearly 50% redundancy in it. If all the redundancy is removed from a written text, it is possible to reduce the size of the text by half (e.g. by omitting all the vowels, books can be half their normal sizes but terrible to read). It is done by first statistically analysing the text. The Huffman algorithm has been extended, for the following reasons:

1) The basic Huffman coding algorithms require the statistical knowledge which is often not available (e.g., live audio, video).

(b) Even when it is available, it could be a heavy overhead especially when many tables had to be sent when a non-order0 model is used, i.e. taking into account the impact of the previous symbol to the probability of the current symbol (e.g., "qu" often come together, ...).

You can find more info in:
www.cs.cf.ac.uk/
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