multimedia information representation - …userspages.uob.edu.bh/.../ho_multimedia4.pdf ·...
TRANSCRIPT
1
1
Multimedia information representation
2
Multimedia information representation
2.2Digitization principles2.2.1 Analog signals2.2.2 Encoder design2.2.3 Decoder design
2.3Text2.3.1 Unformatted text2.3.2 Formatted text2.3.3 Hypertext
2.4Images2.4.1 Graphics2.4.2 Digitized documents2.4.3 Digitized pictures
2.5Audio2.5.1 PCM speech2.5.2 CD-quality audio2.5.3 Synthesized audio
2.6Video2.6.1 Broadcast television2.6.2 Digital video2.6.3 PC video2.6.4 Video content
3 4
Digitization principles
� The conversion of an analog signal into a digital form
� signal encoder.
� signal decoder.
2
5
Signal properties: (a) time-varying analog signal; (b) sinusoidal frequency components;
6
Signal properties: (c) signal bandwidth examples; (d) effect of a limited bandwidth transmission channel.
7
Signal Encoder Design: Circuit Components
8
Signal Encoder Design: Associated Waveform Set
Analog Signal
Low Pass Filtered Version
Clock
Output from Sample & Hold
Quantizer Output
3
9
Alias Signal Generation Due to Under Sampling
10
Example 2.1
11
Quantization Procedure: Source of Errors
bits ofnumber where22
intervalon quantizatimax == nVq
q
n
( )dBlog20Decibelsin Range Dynamic
minmax10 VVDD
=
12
Quantization Procedure: Noise Polarity
4
13
Example 2.2
14
Signal Decoder Design: Circuit Components
15
Signal Decoder Design: Associated Waveform Set
16