Ch 4 Multimedia Elements and Digitization 4A18 and 4A22 (4.2 Analog and…
Ch 4 Multimedia Elements and Digitization
4A18 and 4A22
4.2 Analog and digital data
a lot of information is transmitted in analogue form.
e.g. film camera. magnetic tape of VCR
all electronic devices and modern data transmission channels handle data in binary forms.
e.g. movie DVD, digital camera
Conversion: We have to convert analogue data into digital form before transmission. (also known as Digitization)
Sampling: the process of obtaining discrete data from analogue signal for every fixed time interval.
Quantization: the process of converting the attribute of each data into digital code using a predefined scale.
4.1 Digital Multimedia Elements
Bitmaps: collection of pixels
colour depth: no. of bits that represent pixels
e.g. 1 bit-2 colors, n bit: 2^n,
resolution: no. of pixels per inch (ppi)
JPG, PNG, GIF, TIF, BMP
Vector: mathematical formula
codec: compression and decompression
MP3: Lossy compression
FLAC: Lossless compression
codecs and formats
Common online videos: Adobe Flash video format
deliver: progressive download (youtube) and streaming
MOV, AVI, MP4