Data compression
Unit 1
- Data compression
means to the file size.
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
- 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?
A. Row
B. Column
C. Both row and column
D. 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?
A. Lossy Compression
B. Lossless Compression
C. Both of the above
D. None of the above
Correct option
is B
- Which of the
following are Lossless methods?
A. Run-length
B. Huffman
C. Lempel Ziv
D. All of the above
Correct option is D
- Which of the
following are lossy methods?
A. JPEG
B. MPEG
C. MP3
D. All of the above
Correct option is D
- In how many parts we
can divide audio and video services into broad categories?
A. Two
B. Three
C. Four
D. None of the above
Correct option is B
- Sequence of code
assigned is called
A. code word
B. word
C. byte
D. 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)
- X2
- 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(C2)
- 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
A. compress data by using fewer bits to encode fewer
frequently occuring characters
B. compress data by using fewer bits to encode more
frequently occuring characters
C. compress data by using more bits to encode more
frequently occuring characters
D. expand data by using fewer bits to encode more frequently
occuring characters
Correct option is B
- Huffman coding is an
encoding algorithm used for
A. lossless data compression
B. broadband systems
C. files greater than 1 Mbit
D. 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
A. random length
B. fixed length
C. variable length
D. 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?
A. rectangular code
B. Checksum checking
C. Hamming code
D. Huffman code
Correct option is D
- Which of the
following is the first phase of JPEG?
A. DCT Transformation
B. Quantization
C. Data Compression
D. 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?
A. Run- length encoding
B. Huffman encoding
C. Lempel Ziv encoding
D. JPEG encoding
Correct option is A
- How many passes does
lossy compression makes frequently?
A. One pass
B. Two pass
C. Three pass
D. Four pass
Correct option is B
- Information is the
A. data
B. meaningful data
C. raw data
D. 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
A. simple basic functions
B. sinus functions
C. lines
D. square functions
Correct option is A
- In a typical picture,
most pixels will be
A. equal
B. very different to their neighbors
C. bright
D. 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
A. Fourier transform
B. Wavelets
C. DCT
D. Dolby
Correct option is B
- Which is the image
processing technique used to improve the quality of image for human
viewing?
A. compression
B. enhancement
C. restoration
D. analysis
Correct option is B
- To remove archival
compression and restore the data to column store compression
A. Use ALTER TABLE
B. Use ALTER COLUMN
C. Use ALTER DATABASE
D. All of the mentioned
Correct option is A
- Point out the wrong
A. You can enable or disable ROW or PAGE compression in
online state only
B. When you are compressing indexes, leaf-level pages can be
compressed with both row and page compression
C. Non–leaf-level pages do not receive page compression
D. None of the mentioned
Correct option is A
- What is image?
A. Picture
B. Matrix of pixel
C. Collection of pixel
D. All of these
Correct option is D
- An image transmitted
using wireless network:
A. corrupted as a result of lighting or other atmospheric
B. non-corrupted as a result of lighting or other
atmospheric
C. corrupted as a result of pixel
D. 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?
A. Streaming live
B. Streaming stored
C. Interactive
D. 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?
A. Three
B. Two
C. Four
D. 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.
A. CRC
B. Rectangular code
C. bit-interleaved parity (BIP )
D. Simple parity check
- The minimum sampling
rate is called?
A. Data rate
B. symbol rate
C. Nyquist rate
D. None of the above
Correct option is C
- Spread spectrum is
used for
A. Encrypting signal
B. Hiding signal
C. Encrypting & Hiding signal
D. None of the mentioned
Correct option is C
- Which is a
quantization process?
A. Rounding
B. Truncation
C. Rounding & Truncation
D. None of the mentioned
Correct option is C
- . Quantization is
a……………..process.
A. Non linear
B. Reversible
C. Non linear & Reversible
D. None of the mentioned
Correct option is C
- The mutual
information between a pair of events is
A. Positive
B. Negative
C. Zero
D. 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
A. Hard limiter
B. Two level comparator
C. Hard limiter & Two level comparator
D. None of the mentioned
Correct option is C
- The low pass filter
at the output end of delta modulator depends on
A. Step size
B. Quantization noise
C. Bandwidth
D. None of the mentioned
Correct option is C
- Quantization Matrix
in JPEG compression was introduced because
A. It is computationally more efficient to work with matrix
than with scalar quantization;
B. It allows better entropy encoding due to DC and AC
coefficient distribution in the 8×8 block matrix;
C. 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?
A. Sampling
B. Quantization
C. Both Sampling and Quantization
D. Neither Sampling nor Quantization
Correct option is C
- For a continuous
image f(x, y), Quantization is defined as
A. Digitizing the coordinate values
B. Digitizing the amplitude values
C. All of the mentioned
D. 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?
A. High probability event
B. Low probability event
C. High & Low probability event
D. None of the mentioned
Correct option is B
- The probability
density function of the envelope of narrow band noise is
A. Uniform
B. Gaussian
C. Rayleigh
D. Rician
Correct option is B
- Which model is known
as ignorance model?
A. Physical model
B. Markov model
C. Probability model
D. Composite Source Model
Correct option is C
- Shannons theorem is
also called
A. noiseless coding theorem
B. noisy coding theorem
C. coding theorem
D. noiseless theorem Answer
Correct option is A
- Transform coding,
vector quantization are examples for
A. Pixel
B. compression
C. Transmission
D. 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
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