## All Unit MCQ’s of Data Compression AKTU Exam 2022

In signal processing, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy.

**Also read MCQ’s Questions of Image Processing**

## **Unit 1**

- Data compression means to the file size.

- Increase
- Decrease
- Can’t say
- None of the above Answer

Correct option is B

- Data compression and encryption both work on binary

- False
- True Answer

Correct option is B

- What is compression?

- To compress something by pressing it very hardly
- To minimize the time taken for a file to be downloaded
- To reduce the size of data to save space
- To convert one file to another Answer

Correct option is C

- Data compression usually works by .

- Deleting random bits data
- Finding repeating patterns Answer

Correct option is B

- Why data compressed?

- To optimise the data
- To reduce secondary storage space
- To reduce packet congestion on networks
- Both (B) and (C)

Correct option is D

- Which is a type of data compression?

- Resolution
- Zipping
- Inputting
- Caching

Correct option is B

- Data compression involves

- Compression only
- Reconstruction only
- Both compression and reconstruction
- None of the above

Correct option is C

- Based on the requirements of reconstruction, data compression schemes can be divided into broad classes

- 3
- 4
- 2
- 5

Correct option is C

- compression is the method which eliminates the data which is not noticeable and compression does not eliminate the data which is not

- Lossless, lossy
- Lossy, lossless
- None of these

Correct option is B

- compression is generally used for applications that cannot tolerate any difference between the original and reconstructed data.

- Lossy
- Lossless
- Both
- None of these

Correct option is B

- What is compression ratio?

- The ratio of the number of bits required to represent the data before compression to the number of bits required to represent the data after
- The ratio of the number of bits required to represent the data after compression to the number of bits required to represent the data before
- The ratio of the number of bits required to represent the data after reconstruction to the number of bits required to represent the data before
- The ratio of the number of bits required to represent the data before reconstruction to the number of bits required to represent the data after

Correct option is A

- Suppose storing an image made up of a square array of 256×256 pixels requires 65,536 bytes. The image is compressed and the compressed version requires 16,384 bytes. Then the compression ratio is .

- 1:4
- 4:1
- 1:2
- 2:1

Correct option is B

- Lossy techniques are generally used for the compression of data that originate as analog signals, such as

- Speech
- Video
- Both
- None of these

Correct option is C

- If fidelity or quality of a reconstruction is , then the difference between the reconstruction and the original is .

- High, small
- Small, small
- High, high
- None of the above Answer

Correct option is D

- The development of data compression algorithms for a variety of data can be divided into

- 2
- 3
- 4
- 5

Correct option is A

- Which of the following is true of lossy and lossless compression techniques?

- Lossless compression is only used in situations where lossy compression techniques can’t be used
- Lossy compression is best suited for situations where some loss of detail is tolerable, especially if it will not be detectable by a human
- Both lossy and lossless compression techniques will result in some information being lost from the original file
- Neither lossy nor lossless compression can actually reduce the number of bits needed to represent a file

Correct option is B

- Which of the following would not be suitable for Lossy Compression?

- Speech
- Video
- Text
- Image

Correct option is C

- Which of the following are not in a compressed format?

- MP3
- Bitmap
- MPEG
- JPEG

Correct option is B

- Information theory was given by

- Claude von Regan
- Claude Elwood Shannon
- Claude Monet
- Claude Debussy

Correct option is B

- The unit of information depends on the base of the log. If we use log base 2, the unit is ; if we use log base e, the unit is ; and if we use log base 10, the unit is .

- Hartleys, nats, bits
- Hartleys, bits, nats
- Bits, nats, hartleys
- Bits, hartleys, nats

Correct option is C

- According to Claude Elwood Shannon’s second theorem, it is not feasible to transmit information over the channel with error probability, although by using any coding technique?

- Large
- May be large or small
- Unpredictable
- Small

Correct option is D

- The essential condition/s for a good error control coding technique?

- Better error correcting capability
- Maximum transfer of information in bits/sec
- Faster coding & decoding methods
- All of the above

Correct option is D

- The prefix code is also called as

- Block code
- Convolutional code
- Parity code
- Instantaneous code

Correct option is D

- Self information should be .

- Negative
- Positive
- Both
- None of these

Correct option is B

- A code in which no codeword is a prefix to another codeword is called as

- Prefix cod
- Parity code
- Convolutional code
- Block code

Correct option is A

- The set of binary sequences is called a , and the individual members of the set are called .

- Codewords, code
- Code, codewords
- None of these Answer

Correct option is B

- Full form of ASCII is

- American Standard Code for Information Intercaste
- American Standard Codewords for Information Interchange
- American Standard Code for Information Interchange
- American System Code for Information Interchange

Correct option is C

- Composite source models is a combination or composition of several sources. In which how many source being active at any given time?

- All
- Only one
- Only first three
- None of these

Correct option is B

- For models used in lossless compression, we use a specific type of Markov process called a

- Continous time Markov chain
- Discrete time Markov chain
- Constant time Markov chain
- None of the above

Correct option is B

- Markov model is often used when developing coding algorithms for

- Speech
- Image
- Both
- None of these

Correct option is C

- Which of the following compression type is supported by SQL Server 2014?
- Row
- Column
- Both row and column
- None of the mentioned

Correct option is C

- Point out the correct statement:

- The details of data compression are subject to change without notice in service packs or subsequent releases
- Compression is not available for system tables
- If you specify a list of partitions or a partition that is out of range, an error will be generated
- All of the mentioned

Correct option is D

- In which type of Data Compression, the integrity of the data is preserved?
- Lossy Compression
- Lossless Compression
- Both of the above
- None of the above

Correct option is B

- Which of the following are Lossless methods?
- Run-length
- Huffman
- Lempel Ziv
- All of the above

Correct option is D

- Which of the following are lossy methods?
- JPEG
- MPEG
- MP3
- All of the above

Correct option is D

- In how many parts we can divide audio and video services into broad categories?
- Two
- Three
- Four
- None of the above

Correct option is B

- Sequence of code assigned is called
- code word
- word
- byte
- nibble

Correct option is A

**Unit-II**

- Huffman codes are codes and are optimum for a given model (set of probabilities).

- Parity
- Prefix
- Convolutional code
- Block code

Correct option is B

- The Huffman procedure is based on observations regarding optimum prefix codes, which is/are

- In an optimum code, symbols that occur more frequently (have a higher probability of occurrence) will have shorter codewords than symbols that occur less
- In an optimum code,thetwo symbolsthat occurleast frequently will havethe samelength
- Both (A) and (B)
- None of these

Correct option is C

- The best algorithms for solving Huffman codes

- Brute force algorithm
- Divide and conquer algorithm
- Greedy algorithm
- Exhaustive search

Correct option is C

- How many printable characters does the ASCII character set consists of?

- 128
- 100
- 98
- 90

Correct option is B

- The difference between the entropy and the average length of the Huffman code is called

- Rate
- Redundancy
- Power
- None of these

Correct option is B

- Unit of redundancy is

- bits/second
- symbol/bits
- bits/symbol
- none of these

Correct option is C

- The redundancy is zero when

- The probabilities are positive powers of two
- The probabilities are negative powers of two
- Both
- None of the above

Correct option is B

- Which bit is reserved as a parity bit in an ASCII set?

- Sixth
- Seventh
- Eighth
- Ninth

Correct option is C

- Bits are needed for standard encoding if the size of the character set is X

- X+1
- log(X)
- X
^{2} - 2X

Correct option is B

10. In Huffman coding, data in a tree always occur in

- Leaves
- Roots
- Left sub trees
- None of these

Correct option is A

11. An optimal code will always be present in a full tree?

- True
- False

Correct option is A

- Running time of the Huffman encoding algorithm is

- O(Nlog(C))
- O(Clog(C))
- O(C)
- O(log(C)) Answer

Correct option is B

- Running time of the Huffman algorithm, if its implementation of the priority queue is done using linked lists

- O(log(C))
- O(Clog(C))
- O(C
^{2}) - O(C)

Correct option is C

- The unary code for a positive integer n is simply n followed by a .

- zero, ones
- ones, zero
- None of these

Correct option is B

- The unary code for 4 is .

- 11100
- 11110
- 00001
- 00011

Correct option is B

- In the Tunstall code, all codewords are of However, each codeword represents a number of letters.

- different, equal
- equal, different
- none of these

Correct option is B

- Tunstall coding is a form of entropy coding used for

- Lossless data compression
- Lossy data compression
- Both
- None of these

Correct option is A

- The main advantage of a Tunstall code is that

- Errors in codewords do not propagate
- Errors in codewords propagate
- The disparity between frequencies
- None of these

Correct option is A

- Applications of Huffman Coding

- Text compression
- Audio compression
- Lossless image compression
- All of the above

Correct option is D

- An alphabet consist of the letters A, B, C and D. The probability of occurrence is P(A) = 0.4, P(B)= 0.1, P(C) = 0.2 and P(D) = 0.3. The Huffman code is

- A = 0 B = 111 C = 110 D = 10
- A = 0 B = 11 C = 10 D = 111
- A = 0 B = 111 C = 11 D = 101
- A = 01 B = 111 C = 110 D = 10

Correct option is A

- The basic idea behind Huffman coding is to
- compress data by using fewer bits to encode fewer frequently occuring characters
- compress data by using fewer bits to encode more frequently occuring characters
- compress data by using more bits to encode more frequently occuring characters
- expand data by using fewer bits to encode more frequently occuring characters

Correct option is B

- Huffman coding is an encoding algorithm used for
- lossless data compression
- broadband systems
- files greater than 1 Mbit
- lossy data compression

Correct option is A

- A Huffman encoder takes a set of characters with fixed length and produces a set of characters of
- random length
- fixed length
- variable length
- constant length

Correct option is C

- A Huffman code: A = 1, B = 000, C = 001, D = 01 , P(A) = 0.4, P(B) = 0.1, P(C) = 0.2, P(D) = 0.3 The average number of bits per letter is

- 0 bit
- 1 bit
- 0 bit
- 9 bit

Correct option is C

- Which of the following is not a part of the channel coding?
- rectangular code
- Checksum checking
- Hamming code
- Huffman code

Correct option is D

- Which of the following is the first phase of JPEG?
- DCT Transformation
- Quantization
- Data Compression
- None of the above

Correct option is D

- Which type of method is used is used to compress data made up of combination of symbols?
- Run- length encoding
- Huffman encoding
- Lempel Ziv encoding
- JPEG encoding

Correct option is A

- How many passes does lossy compression makes frequently?
- One pass
- Two pass
- Three pass
- Four pass

Correct option is B

- Information is the
- data
- meaningful data
- raw data
- Both A and B

Correct option is B

**Unit-III**

- In dictionary techniques for data compaction, which approach of building dictionary is used for the prior knowledge of probability of the frequently occurring patterns?

- Adaptive dictionary
- Static dictionary
- Both
- None of the above

Correct option is B

- If the probability of encountering a pattern from the dictionary is p, then the average number of bits per pattern R is given by

- R=21-12p
- R=9-p
- R=21-p
- R=12-p

Correct option is A

- Static dictionary –

- permanent
- sometimes allowing the addition of strings but no deletions
- allowing for additions and deletions of strings as new input symbols are being read
- Both (A) and (B)
- Both (A) and (C)

Correct option is D

- Adaptive dictionary –

- holding strings previously found in the input stream
- sometimes allowing the addition of strings but no deletions
- allowing for additions and deletions of strings as new input symbols are being read
- Both (A) and (B)
- Both (A) and (C)

Correct option is E

- LZ77 and LZ78 are the two algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978

- Lossy data compression
- Lossless data compression
- Both
- None of the above

Correct option is B

- Deflate =………….

- LZ78 + Huffman
- LZ77 + Huffman
- LZW + Huffman
- None of these

Correct option is B

- Full form of GIF

- Graphics Interchange Form
- Graphics Inter Format
- Graphics Interchange Format
- Graphics Interact Format

Correct option is C

- LZ78 has compression but very decompression than

- fast, slow
- slow, fast
- None of these

Correct option is B

- Compression packages which use an LZ77-based algorithm followed by a variable-length coder.

- PKZip
- Zip
- PNG
- All of the above

Correct option is D

- Application of LZW

- GIF
- Zip
- PNG
- All of the above

Correct option is A

- Algorithm used for solving temporal probabilistic reasoning

- Depth-first search
- Hidden markov model
- Hidden markov model
- Breadth-first search

Correct option is C

- Where does the Hidden Markov Model is used?

- Understanding of real world
- Speech recognition
- Both
- None of the above

Correct option is B

- A coding scheme that takes advantage of long runs of identical symbols is called as

- Move-to-front coding
- Binary coding
- Huffman coding
- Move-to-back coding

Correct option is A

- The idea with wavelets is to represent a complicated function by
- simple basic functions
- sinus functions
- lines
- square functions

Correct option is A

- In a typical picture, most pixels will be
- equal
- very different to their neighbors
- bright
- very similar to their neighbors

Correct option is C

- Without losing quality, JPEG-2000 can achieve compression ratios of

- 2:1
- 200:1
- 2000:1
- 20:1

Correct option is B

- The best visual compression quality is achieved using
- Fourier transform
- Wavelets
- DCT
- Dolby

Correct option is B

- Which is the image processing technique used to improve the quality of image for human viewing?
- compression
- enhancement
- restoration
- analysis

Correct option is B

- To remove archival compression and restore the data to column store compression
- Use ALTER TABLE
- Use ALTER COLUMN
- Use ALTER DATABASE
- All of the mentioned

Correct option is A

- Point out the wrong
- You can enable or disable ROW or PAGE compression in online state only
- When you are compressing indexes, leaf-level pages can be compressed with both row and page compression
- Non–leaf-level pages do not receive page compression
- None of the mentioned

Correct option is A

- What is image?
- Picture
- Matrix of pixel
- Collection of pixel
- All of these

Correct option is D

- An image transmitted using wireless network:
- corrupted as a result of lighting or other atmospheric
- non-corrupted as a result of lighting or other atmospheric
- corrupted as a result of pixel
- none of above

Correct option is A

**Unit-IV**

- Which of the following characterizes a quantizer

- Quantization results in a non-reversible loss of information
- A quantizer always produces uncorrelated output samples
- The output of a quantizer has the same entropy rate as the input
- None of the above

Correct option is A

- What is the signal-to-noise ratio (SNR)?

- The ratio of the average squared value of the source output and the squared error of the source output
- The ratio of the average squared value of the source output and the mean squared error of the source output
- The ratio of the average squared value of the source output and the absolute difference measure of the source output
- None of the above

Correct option is B

- The output signal of a scalar quantizer has property

- The output is a discrete signal with a finite symbol alphabet
- The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet)
- The output signal may be discrete or continuous
- None of the above

Correct option is B

- What is a Lloyd quantizer?

- For a given source, the Lloyd quantizer is the best possible scalar quantizer in ratedistortion That means, there does not exist any other scalar quantizer that yields a smaller distortion at the same rate.
- The output of a Lloyd quantizer is a discrete signal with a uniform pmf
- Both (A) and (B)
- A Lloyd quantizer is the scalar quantizer that yields the minimum distortion for a given source and a given number of quantization

Correct option is D

- Which of the following statement is correct for comparing scalar quantization and vector quantization?

- Vector quantization improves the performance only for sources with memory. For iid sources, the best scalar quantizer has the same efficiency as the best vector quantizer
- Vector quantization does not improve the rate-distortion performance relative to scalar quantization, but it has a lower complexity
- By vector quantization we can always improve the rate-distortion performance relative to the best scalar quantizer
- All of the above

Correct option is C

- If {x}
_{n}is the source output and {y}_{n}is the reconstructed sequence, then the squared error measure is given by

- d(x, y) = (y – x)
^{2} - d(x, y) = (x – y)
^{2} - d(x, y) = (y + x)
^{2} - d(x, y) = (x – y)
^{4}

Correct option is B

- If {x}
_{n}is the source output and {y}_{n}is the reconstructed sequence, then the absolute difference measure is given by

- d(x, y) = |y – x|
- d(x, y) = |x – y|
- d(x, y) = |y + x|
- d(x, y) = |x – y|
^{2}

Correct option is B

- The process of representing a possibly infinite set of values with a much set is called quantization

- Large, smaller
- Smaller, large
- None of these

Correct option is A

- The set of inputs and outputs of a quantizer can be

- Only scalars
- Only vectors
- Scalars or vectors
- None of these

Correct option is C

- Which of the folowing is/are correct for uniform quantizer

- The simplest type of quantizer is the uniform quantizer
- All intervals are the same size in the uniform quantizer, except possibly for the two outer intervals
- The decision boundaries are spaced evenly
- All of the above

Correct option is D

- If a Zero is assigned a decision level, then what is the type of quantizer?

- A midtread quantizer
- A midrise quantizer
- A midtreat quantizer
- None of the above

Correct option is B

- If a Zero is assigned a quantization level, then what is the type of quantizer?

- A midtread quantizer
- A midrise quantizer
- A midtreat quantizer
- None of the above

Correct option is A

- The main approaches to adapting the quantizer parameters:

- An off-line or forward adaptive approach
- An on-line or backward adaptive approach
- Both
- None of the above

Correct option is C

- Uniform quantizer is also called as

- Low rise quantizer
- High rise quantizer
- Mid rise quantizer
- None of the above

Correct option is C

- Non uniform quantizer

- Decrease
- Increase
- Doesn’t change
- None of the above

Correct option is A

- The spectral density of white noise is .

- Poisson
- Exponential
- Uniform
- Gaussian

Correct option is C

- Which audio/video refers to on-demand requests for compressed audio/video files?
- Streaming live
- Streaming stored
- Interactive
- None of the above

Correct option is B

- According to Nyquist theorem, how many times the highest frequency we need to sample an analog signal?
- Three
- Two
- Four
- None of the above

Correct option is B

- Which encoding is based on the science of psychoacoustics, which is the study of how people perceive sound?

- Predictive
- Perceptual
- Both of the above
- None of the above

Correct option is B

- SDH uses to measure block errors.
- CRC
- Rectangular code
- bit-interleaved parity (BIP )
- Simple parity check

- The minimum sampling rate is called?
- Data rate
- symbol rate
- Nyquist rate
- None of the above

Correct option is C

- Spread spectrum is used for
- Encrypting signal
- Hiding signal
- Encrypting & Hiding signal
- None of the mentioned

Correct option is C

- Which is a quantization process?
- Rounding
- Truncation
- Rounding & Truncation
- None of the mentioned

Correct option is C

- . Quantization is a……………..process.
- Non linear
- Reversible
- Non linear & Reversible
- None of the mentioned

Correct option is C

- The mutual information between a pair of events is
- Positive
- Negative
- Zero
- All of the mentioned

Correct option is D

- The SNR value can be increased by the number of levels.

- Increasing
- Decreasing
- Does not depend on
- None of the mentioned

Correct option is A

- 1 bit quantizer is a
- Hard limiter
- Two level comparator
- Hard limiter & Two level comparator
- None of the mentioned

Correct option is C

- The low pass filter at the output end of delta modulator depends on
- Step size
- Quantization noise
- Bandwidth
- None of the mentioned

Correct option is C

- Quantization Matrix in JPEG compression was introduced because
- It is computationally more efficient to work with matrix than with scalar quantization;
- It allows better entropy encoding due to DC and AC coefficient distribution in the 8×8 block matrix;
- It allows better differentiation of DC and AC coefficients in the 8×8 block matrix than a scalar quantization;

Correct option is C

- What property has the output signal of a scalar quantizer
- The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet).
- The output is a discrete signal with a finite symbol
- The output signal may be discrete or continuous

Correct option is A

**Unit-V**

- Characteristic of a vector quantizer

- Multiple quantization indexes are represented by one codeword
- Each input symbol is represented by a fixed-length codeword
- Multiple input symbols are represented by one quantization index
- All of the above

Correct option is C

- Vector quantization is rarely used in practical applications, why?

- The coding efficiency is the same as for scalar quantization
- The computational complexity, in particular for the encoding, is much higher than in scalar quantization and a large codebook needs to be stored
- It requires block Huffman coding of quantization indexes, which is very complex
- All of the above

Correct option is B

- Let N represent the dimension of a vector quantizer. What statement about the performance of the best vector quantizer with dimension N is correct?

- For N approaching infinity, the quantizer performance asymptotically approaches the rate- distortion function (theoretical limit)
- By doubling the dimension N, the bit rate for the same distortion is halved
- The vector quantizer performance is independent of N
- All of the above

Correct option is A

- Which of the following is/are correct for the advantage of vector quantization over scalar quantization.

- Vector Quantization can lower the average distortion with the number of reconstruction levels held constant
- Vector Quantization can reduce the number of reconstruction levels when distortion is held constant
- Vector Quantization is also more effective than Scalar Quantization When the source output values are not correlated
- All of the above

Correct option is D

- Vector quantization is used for

- Lossy data compression
- Lossy data correction
- Pattern recognition
- All of the above

Correct option is D

- The Linde–Buzo–Gray algorithm is a quantization algorithm to derive a good codebook.

- Scalar
- Vector
- Both
- None of the above

Correct option is B

- Vector quantization is used in

- Video coding
- Audio coding
- Speech coding
- All of the above

Correct option is C

- What are processes (Techniques) used in video coding?

- Partition of frames into macroblocks
- Form of Vector Quantization
- Both (A) & (B)
- None of these

Correct option is C

- The process of converting the analog sample into discrete form is called

- Modulation
- Multiplexing
- Quantization
- Sampling

Correct option is C

10 . The sequence of operations in which PCM is done is

- Sampling, quantizing, encoding
- Quantizing, encoding, sampling
- Quantizing, sampling, encoding
- None of the above

Correct option is A

- To convert a continuous sensed data into Digital form, which of the following is required?
- Sampling
- Quantization
- Both Sampling and Quantization
- Neither Sampling nor Quantization

Correct option is C

- For a continuous image f(x, y), Quantization is defined as
- Digitizing the coordinate values
- Digitizing the amplitude values
- All of the mentioned
- None of the mentioned

Correct option is B

- The resulting image of sampling and quantization is considered a matrix of real numbers. By what name(s) the element of this matrix array is called

- Image element or Picture element
- Pixel or Pel
- All of the mentioned
- None of the mentioned

Correct option is C

- Which conveys more information?
- High probability event
- Low probability event
- High & Low probability event
- None of the mentioned

Correct option is B

- The probability density function of the envelope of narrow band noise is
- Uniform
- Gaussian
- Rayleigh
- Rician

Correct option is B

- Which model is known as ignorance model?
- Physical model
- Markov model
- Probability model
- Composite Source Model

Correct option is C

- Shannons theorem is also called
- noiseless coding theorem
- noisy coding theorem
- coding theorem
- noiseless theorem Answer

Correct option is A

- Transform coding, vector quantization are examples for
- Pixel
- compression
- Transmission
- Lossy compression Answer

Correct option is D

19. Entropy Coding is an

- Lossless
- Lossy
- 0
- None

Correct option is A

20. is normally used for the data generated by scanning the documents, fax machine, typewriters etc.

- Huffman Coding
- Transformation Coding
- Vector Quantization
- Runlength Encoding

Correct option is D

21. Compression Technique used in Image Video is

- Huffman Coding
- Transformation Coding
- Entropy Coding
- Differential Encoding

Correct option is B

22. Compression Technique used in Audio is

- Differential Encoding
- Transformation Encoding
- Entropy Coding
- Differential & Transformation Encoding

correct option is D

23. Expansion of LZ Coding is

- Lossy
- Lossless
- Lempel-ziv-welsh
- Lempel-ziv

Correct option is D

24. Expansion of LZW Coding is

- Lossy
- Lossles
- Lempel-ziv
- Lempel-ziv-welsh

Correct option is D