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Chapter 4: Multimedia Elements and Digitization - Coggle Diagram
Chapter 4: Multimedia Elements and Digitization
4.1 Digital Multimedia Elements
Graphic
Audio
Video
Handed In Before
4.2 Analogue Data and Digital Data
Characteristics of analogue data and digital data
(Analogue Data V.S. Digital Data)
Ways of measurement
Continuous signals of amplitude and frequency of the source are measured
Information is represented in discrete form. In other words, a set of finite numbers of symbols (usually ‘0’ and ‘1’) is used to represent a piece of information
Efficiency in data storage
Low: The physical size of storage media such as cassette tape and video tape are much larger than the corresponding digital storage media. Their life-time is much shorter
High: Data can be stored in compact media such as CD-ROM and flash memory for long term storage
Efficiency in data transmission
High rate of transmission error
Low rate of transmission error
Accuracy of information
Accuracy depends on the sampling technique used
Lower accuracy: Not all information is converted and recorded in the process of converting analogue signals to digital signals
Replication
Absolute replication is nearly impossible. Data is lost in the replication process
Absolute replication and error-free transmission of data are possible and easy
Mode of data access
Mostly sequential access
Direct access is possible, depending on the media used for storage
Efficiency on data analysis
Low : Analogue content is difficult to search for, analyze and reconstruct to produce other information
High : Digital contents can be efficiently reused or processed by computers to generate information
Application of digital data in IT
All electronic devices including computers and modern data transmission channels handle data in binary forms
Digital data and computer programs can be represented in sequences of binary numbers
This makes operations of electronic devices on digital data such as storage, transmission manipulation and duplication highly precise and efficient
Conversion between analogue data and digital data
Digitization is the process of converting analogue data into digital data.
Digitization involves two procedures: sampling and quantization
Sampling
The process of obtaining discrete sample data from the continuous analogue signal for every fixed time interval
Quantization
The process of converting the attribute of each sample data into a digital code using a predefined scale