Top 100+ Multimedia Compression Interview Questions And Answers

Question 1. Explain The Jpeg Modes Of Operations?

Answer :

Following are the JPEG operation modes:

Lossless Mode: Every pixel in the image is encoded despite the fact that the compression ratio is low.

Sequential Mode: A single scan from left-to-right and top-to-bottom compresses the photograph.

Progressive Mode: Multiple scans are used to compress the picture. The transmission time is long.

Hierarchical Mode: Multiple resolutions are used to compress the picture. Hence the decrease decision is accessed first which does now not require the decompressing the complete resolution of the picture.

Question 2. What Is Discrete Cosine Transform?

Answer :

It is just like Fast Fourier Transform.
The frame blocks of size 8x8 or 16x16 pixels are represented as frequency components.
This transforms into frequency domain via implementing fashionable system.
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Question three. What Is Motion Estimation?

Answer :

Two successive video frames regularly have small differences.
MPEG trendy has a widespread to lessen this temporal redundancy.
Question 4. What Is Reduction Of The Resolution?

Answer :

Performs the conversion of RGB-color area into YUV colour additives.
The chrominance additives U and V may be decreased to 1/2 of the pixels inside the horizontal path.
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Question 5. Do You Know About three-level Hierarchical Jpeg Encoder?

Answer :

Down-sample the factors of decision with the aid of 2 for each dimension.

For instance - ,Reduce the 640 x 480 decision to 320 x 240 decision.

Code the smaller photo with some other JPEG mode.
Decode the picture and up the pattern encoded photograph.
Encode the distinction between the decoded photo and the original photograph.
The above system can be repeated for multiple times.
This technique provides high quality pictures with low resolution display.
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Question 6. Explain Some Major Steps For Jpeg Compression?

Answer :

Following are the primary steps that are worried in JPEG compression:

Discrete Cosine Transformation.
Quantization.
Zigzag Scan.
DPCM on DC thing.
RLE on AC Components
Entropy Coding.
Question 7. Explain The Features Of Jpeg 2000 Standard?

Answer :

Following are the JPEG 2000 capabilities.:

Compression performance is at low bit-fee.
Both lossless and lossy compression is executed with a unmarried code circulation.
The transmission in noise environment may be performed with low bit-blunders fee.
It is relevant for each grey and colour pics.
Bi-level imagery, herbal imagery and laptop generated imagery is applicable for grey and color snap shots.
It is interactive with MPEG-4 fashionable.
Wavelets will get replaced with Discrete Cosine Transform.
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Question 8. What Is Mpeg-2?

Answer :

MPEG-2 is one of the global requirements for compressing video signals.
Videos can be compressed prior to transmission or garage.
The approximate compression ratio is 50:1 of the virtual size.
MPEG-2 preferred is extensively applied in digital TV transmission with 200 million decoders.
MPEG-2 trendy exploits the redundancies inside the authentic sign.
Question nine. Do You Know What Are The Desirable Properties Of A Speech Coder?

Answer :

Following are the proper properties of speech coders:

Low Bit-Rate.
Low Memory Size
Low Coding Delay
High Speech Quality
Robustness Across Different Languages / Speakers
Robustness in the Presence of Channel Errors
Good Performance on Non-Speech Signals, like telephone signaling.
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Question 10. Tell Me What Is Vocoder?

Answer :

Vocoder is one of the audio processors
The function factors of an audio sign are captured by means of Vocoder.
These function signals are used to affect the opposite audio signals.
It is extensively used in speech synthesis.
A aspect called Formant describes the frequency of a legitimate and noise components which can be associated.
The audio output of Vocoder has synthesized sound this is modulated by way of a clear out.
The synthesized sound is pulsed to the pace of the person input voice with the tonal traits of the voice.
Question 11. What Is Mpeg-1 Audio Compression Standard?

Answer :

MPEG-1 is a lossy compression popular for both video and audio.
It compresses VHS satisfactory raw virtual video right down to 1.5Mega Bits consistent with Second.
The compression ration is 26:1
MPEG-1 delivered MP3 audio layout.
The preferred includes -

Systems which include synchronization of video, audio and other records.
Compressed Video content material.
Compressed Audio content.
Conformance trying out.
Reference software.
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Question 12. Do You Know What Is Delta Modulation And Explain Its Features?

Answer :

A method that converts analog to virtual and virtual to analog signal conversion:

It is to transmit voice information.
It encodes the variations between successive samples into n-bit records streams.
The transmitted facts is decreased to one-bit information stream.
Following are the features of Delta Modulation:

A series segments are used to approximate the analog sign.
The approximated sign is compared with analog wave for determining the growth or decrease in relative amplitude.
Only the boom or decrease of the sign amplitude is simplest despatched.
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Question 13. Do You Know What Is Optimfrog?

Answer :

OptimFROG is one of the lossless audio compression scheme.
The goal of OptimFROG is to reduce the scale of an audio file to the most.
It allows bit same recuperation for all inputs.
It is like ZIP kind of compression and specialized for audio records compression.
OptimFROG obtains asymptotically the fine lossless compression ratios for audio files.
It can be plugged-in with Windows, Linux, Mac running structures for Windows Media Player, Foobar2000, Winamp2/3/5, XMPLay, QCD players.
It helps for all integer PCM wave formats up to 32 bits.
Question 14. What Is Lempel-ziv-welch (lzw) Coding Scheme?

Answer :

LZW is a loss less information compression algorithm popular international extensive.
This algorithm has high throughput capacity in implementation.
The excessive stage set of rules is going like this:

Assign all the strings to dictionary.
Identify the longest string L to be had within the dictionary which suits the prevailing input.
Find the dictionary index for L to get the output and put off L from the enter.
Concatenate L by way of the subsequent image of the enter to the dictionary.
Repeat the system from step 2.
Question 15. What Is Jpeg Encoder?

Answer :

JPEG encoder has 3 major blocks particularly, Forward Discrete Cosine Transform, Quantizer and Entropy Encoder.
JPEG encoder is the primary component for lossless and hierarchical encoders.
It is suitable for grey scale and shade pix.
Each photo is divided into 8 x 8 blocks.
A organization of four tables are special via JPEG.
If the desk has first-rate cost with 1, then the best is high-quality and compression is lowest.
If the table has pleasant cost with 2, then the great is high-quality and compression is highest.
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Question 16. What Is Lossless Source Coding?

Answer :

Lossless supply coding is one of the information compression requirements.
Lossless supply coding lets in the decompression assures the exact copy of the original statistics.
Images, audio and video documents use lossless supply compression popular.
Lossless supply encoding is appropriate for compressing text files.
It produces constant length symbols.
Question 17. Tell Me About Nyquist Rule?

Answer :

Nyquist Rule is one of the mathematical expressions.
While sampling the frequency, the sampling frequency is expanded two times.
The sign have to no longer contain a Fourier spectrum with sine or cosine above the frequency.
The sign can be reconstructed with the aid of sampling at twice the frequency.
The sign can't be reconstructed if the signal isn't sampled at two times the frequency.
Nyquist is needed simplest for virtual sign processing however not for analog singnal processing.
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Question 18. Can You Explain What Is Mpeg-7?

Answer :

MPEG-7 is an ISO/IEC popular for MPEG.
MPEG-7 isn't geared toward anybody of the programs especially.
MPEG-7 affords a set of audio and video description equipment for creation of descriptions.
It allows efficient get admission to to multimedia content.
MPEG-7 lets in various granularities in its description.
When the content material is encoded, it offers certain members of the family in synchronous style.
The descriptions to factors for special objects like audio / video / photo gadgets inside a particular scene, is connected by descriptions.
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Question 19. Do You Know What Is Mpeg-21?

Answer :

A multimedia framework to allow transparent and augmented use of multimedia sources.
Complete multimedia content advent, manufacturing, transport is executed with MPEG-21.
MPEG-21 allows to apply the prevailing multimedia components to be used together.
The basic architectural concept of MPEG-21 framework is the Digital Item.
Digital Items are virtual objects which incorporates standard illustration and identity of multimedia.
Digital Item is a aggregate of assets consisting of motion pictures, audio tracks, snap shots, metadata and structure that describes the connection amongst resources.
Question 20. Do You Know What Applications Are Suitable For Using Mpeg-21?

Answer :

MPEG-21 is appropriate for style of packages.

They are:

Digital Libraries
Asset control
Cataloguing in book
Broadcast usage
Publishing
Trade transactions
Content filtering
Music/Video Releases
Question 21. Explain The Advantages And Disadvantages Of Video Compression?

Answer :

Following are the blessings of Video Compression:

Occupies much less disk space.
Reading and writing is quicker.
File transferring is faster.
The order of bytes is independent.
Following are the negative aspects of video compression:

Compilation want to be achieved once more for compression.
Errors might also occur at the same time as transmitting records.
The byte / pixel dating is unknown
Has to decompress the previous statistics.
Question 22. Do You Know What Is Compression? Why Is It Necessary To Compress Files?

Answer :

Compression refers to decreasing the authentic record length.
Video and audio files devour extra disk space as compared to file documents.
While sending the files as attachments in an e mail, the e-mail may not send the document, as the scale is extra that it takes.
Compressed files with less disk area can be sent as attachments in an e-mail.
Compressed files reduce time to connect, add and download documents.
Some of the internet servers need handiest compressed documents to add and download.