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Ch4.1 Digital Multimedia Elements - Coggle Diagram
Ch4.1 Digital Multimedia Elements
Graphics
Bitmap
a bitmap image is a collection of colour dots called pixels arranged in rows and columns.
A pixel is the smallest picture element that can be shown on a computer screen.
The larger the colour depth, the larger the number of
colours can be displayed in the image.
The number of colours can be displayed in a pixel is determined by the number of bits used to represent the pixel (known as colour depth).
Vector grapics
video
Is a sequence of full-motion images together with sound tracks.
The file size of it can be very large.
Factors affecting the size of a video file
factors
duration
Play time of a video clip
compression method
Reduction of quantity of data of video clips by
changing the content or the way of representation of video frames
frame rate
Number of frames
displayed per second
colour depth
Number of bits used to represent a pixel
frame size
Number of horizontal and vertical pixels on each video picture (frame)
video files can be compressed into different video file formats for different playback media
audio
Audio files in a computer are the digitized data of music, speech and any kind of audio signals.
The quality of a digital audio file is determined by its bit resolution and sampling rate.
Bit resolution:
Audio data: can be stored either in uncompressed or compressed format
WAV: the most popular type of uncompressed audio file format
Sampling rate:
number of sample taken each second during the conversion process
measured in (Hz)
higher the sampling rate, higher quality of the digital audio will be
Stereo audio:
contains two streams of audio signals, known as left and right sound track.
Mono:
contains only one sound track