1. Efficient Huffman Decoding Aggarwal, M. and Narayan, A., International Conference on Image Processing, vol. 1, pp. 936 – 939, 2000 Presenter :Yu-Cheng Cheng

2. Outline Introduction The Decoding Algorithm Discussion and Conclusions

3. Introduction Huffman codes are being widely used in image and video compression. The paper has proposed a two-step algorithm to decode Huffman codes.

4. Outline Introduction The Decoding Algorithm Discussion and Conclusions

5. The Decoding Algorithm The first step, the subset or partition corresponding to the leading codeword is determined. The paper defines a function lmbc(), which takes a sequence of bits as input and returns the position of the first-bit-change starting from the leading bit.

6. The Decoding Algorithm Fig.1 The Huffman tree of codewords

7. The Decoding Algorithm Table 1. Huffman Table

8. The Decoding Algorithm Example, consider the bitstream B = 00000000111010 which corresponds to gbpc.

9. The Decoding Algorithm The paper notes that the codewords in a particular partition of Table 1 need not have the same length. The paper creates a one-dimensional array actlen.

10. The Decoding Algorithm Table 2. Modified Huffman Table

11. The Decoding Algorithm Fig. 2. The decoding data structures

12. Outline Introduction The Decoding Algorithm Discussion and Conclusion

13. Discussion and Conclusions The proposed algorithm requires very few computations to decode a codeword, and the complexity is independent of the height h of the Huffman tree.