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Reg. No. :

M.E./M.Tech. DEGREE EXAMINATION, JUNE 2011.

Common to M.E. – Computer and Communication/ M.E. – Communication Systems

Second Semester

251204 — MULTIMEDIA COMPRESSION TECHNIQUES

(Regulation 2010)

Time : Three hours Maximum : 100 marks

Answer ALL questions.

PART A — (10 × 2 = 20 marks)

1. How is information quantified?

2. Mention the models used in lossless compression schemes.

3. In what way adaptive Huffman coding differ from Huffman coding?

4. What is static and adaptive dictionary?

5. What is frequency or auditory masking?

6. Write the expression for the A law and µ law of companding.

7. Write about the noises that occur in Delta modulation?

8. What are the advantages of DCT over other image transforms?

9. What is error resilience coding? Mention examples.

10. What is the function of the deblocking filter?

PART B — (5 × 16 = 80 marks)

11. (a) (i) Estimate the amount of storage required for different classes of

multimedia data and justify the need for multimedia compression

techniques. (8)

(ii) Outline the taxonomy of compression techniques for multimedia

and briefly explain their salient features. (8)

Or

(b) Describe vector quantization theory. Discuss its merits over scalar

quantization. (16)

Question Paper Code : 31183

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31183 2

12. (a) (i) Describe the steps involved in Huffman encoding. Given the eight

symbols A, B, C, D, E, F, G, and H with probabilities 1/30, 1/30,

1/30, 2/30, 3/30, 5/30, 5/30, and 12/30, draw the Huffman tree for

these symbols and compute the average code size and efficiency. (8)

(ii) Explain arithmetic coding. (8)

Or

(b) Explain the basic idea of dictionary based compression techniques.

Explain how the LZW dictionary encoding is done. Illustrate with an

example. (16)

13. (a) Give a detailed description of G.722 audio coding scheme. (16)

Or

(b) What are channel vocoders. Describe the concept of CELP vocoders in

speech compression. (16)

14. (a) Describe the various steps of JPEG compression process. Enumerate the

difference between JPEG and JBIG standards. (16)

OR

(b) (i) What is sub band coding. Explain the principle of Quadrature

mirror filters. (10)

(ii) Explain the basic concept of wavelet transform for image

compression. (6)

15. (a) (i) Explain with block diagram, the MPEG4 video encoder and decoder.

(8)

(ii) Outline the key features of various MPEG standards. (8)

Or

(b) (i) Describe the encoding stages of a H.261 source encoder. (8)

(ii) Briefly explain the DVI technology for real time compression. (8)

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