Huffman Coding with norm2huff and huff2norm function

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Ibnu Darajat 2019-8-14

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https://ww2.mathworks.cn/matlabcentral/answers/476048-huffman-coding-with-norm2huff-and-huff2norm-function

评论： Walter Roberson 2019-8-15

I have an 8000 information signal and then it is compressed using huffman coding (norm2huff) and then the signal is transmitted over the rayleigh channel. And during the decompression process using the huff2norm function, the number of information signals increases to 8932. Can you explain why that happened? Thanks before

[zipped,info] = norm2huff(quantized_sound); %compress
unzipped = huff2norm(uint8(decoded),info); %de-compress

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Walter Roberson 2019-8-14

在 MATLAB Online 中打开

Imagine that you have a huffman dictionary:

-> Darajat
-> wins!
-> Ibnu

Now let us imagine that you have the "message" Darjat to send. That gets encoded as 01 . Now let that 01 get transmitted, but let there be a bit error on the 01 such that what is received after detection and correction is 11 . Decode that bit stream according to the dictionary. You start from the beginning of the stream and see that you have a 1 in hand. Match that to the dictionary. Temporarily eliminate all of the items in the dictionary that start with 0, and retain the rest and discard the leading 1 bit. That gives you the dictionary that contains only (empty) -> Ibnu . Are you at a dictionary with a single empty entry? Yes you are -- emit the corresponding string and restore the full dictionary, so you emit Ibnu and continue on to the second 1 out of the 11 that the receiver got. Some decoding logic again, so the 1 matches and again you emit Ibnu . So now you have emitted Ibnu Ibnu -- two items where you only expected one item, Darajat

If you have even a single bit error in a huffman sequence, then everything after that can get messed up in decoding and the number of items emitted can be quite different than if you did not have the error.

Ibnu Darajat 2019-8-15

In Huffman's theory, after data compression we can calculate the entropy, efficiency, and average code length. in this function, can we calculate the average code length (avglen)?