Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 4 Multimedia Elements and Digitization (4.2 Analog and digital…
Chapter 4 Multimedia Elements and Digitization
4.1 Digital Multimedia Elements
Graphics
Bitmaps
pixels: smallest picture element
colour depth: number of bits used to represent pixel colour
1 bit: 2 colours
2 bit: 4 colors
3 bit: 8 colours
24 bit: 16.7 milion colours
n bit: 2^n
resolution: number of pixels per inch (screen)
resolution: dimensions of image (e.g. 800 x 600)
Common file formats:
JPG: small file size
PNG: medium file size, retain 100% quality
GIF: supports animation (stickers), only 256 colours
TIF: used in fax and medical field
BMP: large file size
Vector graphics: vector objects are defined by mathematical formula
Audio
bit resolution: bit resolution increases, audio quality increase
sampling rate: sampling rate increases, audio quality increase
common formats
MP3: small file size, supports streaming
M4A: high quality, quite large file size, supports streaming
WAV: large file size
AAC: high quality, supports streaming
WMA: Windows audio format, supports streaming
Video
Common formats
MP4: high quality, small file size, streaming (live broadcast)
AVI: large file size
MOV: large file size
FLV: small file size, streaming (live broadcast)
4.2 Analog and digital data
Compare analog and digital data
Analog
Nature: Continuous of signal data
stored on cassette tape
lower precision
more difficult to duplicate
sequential access
Digital
Nature: Discrete data
stored on CDs, DVDs, cloud storage
higher precision
easy to duplicate
direct access
Applications of digital data in daily life
Convert analog to digital data
Digitization of multimedia elements