Multimedia Communications: Overview of Signal Compression

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Multimedia CommunicationsOverview of Signal
Compression

• mmc2.01

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Applications and Bit Rates
mmc2.02
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Dimensions of Performance I

• Quality
• Bit Rate
• Delay
• Complexity
• mmc2.03

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Dimensions of Performance II

• Resiliency to
• Transmission Errors
• Storage Defects
• Environmental Imperfections
• Multiple Stages of Coding
• Information Hiding
• mmc2.04

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Block Diagram of Communication System
mmc2.05
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Recent Applications of Compression

• IMT-2000
• DAB
• HDTV
• Digital Movies
• Digital Libraries
• Internetworking
• Personal Multimedia
• 
  Convergence
• mmc2.06

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Grades of Compression

• Lossy Compression
• Lossless Compression
• Perceptually Lossless Compression
• mmc2.07

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Rate-Distortion Perspective
mmc2.08
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The Principles of Compression

• Removal of Redundancy
• Removal of Irrelevancy
• mmc2.09

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The Disciplines of Compression

• Signal Processing
• DSP and Computing
• Coding Theory
• Information Theory
• Psychophysics
• mmc2.10

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Measurement of Signal Quality

• Objective Measures
• Subjective Measures
• Functional Measures
• 6R 10 log10(1/sfm)
• MOS and MIS
• 10 log 10 (1/PL)
• mmc2.11

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Subjective Scales of Quality and Impairment
Level Number Signal Quality Impairment
1 Bad Very Annoying 2 Poor Annoying
3 Fair Slightly Annoying
4 Good Perceptible but not Annoying
5 Excellent Imperceptible mmc2.12
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Measurement of Bit Rate

• Sum of Subsystem Bit Rates
• Sum Sampling Rate Average Bit Rate in
  Qzn.
• Example of PCM
• Example of CELP Speech Coding
• Example of DCT Audio Coding
• Example of MC-DCT Video Coding
• Perceptual Entropy
• mmc2.13

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Measurement of Communication Delay

• Encoder Delay
• Decoder Delay
• Communication Subsystem Delays
• mmc2.14

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Measurement of Complexity

• Encoder Complexity
• Decoder Complexity
• Communication System Complexity
• Memory
• Arithmetic
• Architecture
• NSP, DSP, IC
• mmc2.15

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Techniques of Compression I

• Quantization
• scalar quantization
• vector quantization
• perceptual quantization
• embedded quantization
• multiple description quantization
• mmc2.16

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Techniques of Compression II

• Redundancy Removal
• linear prediction
• motion compensation
• sub-band filterbanks
• linear transforms
• statistical and object models
• analysis-by-synthesis
• mmc2.17

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Multimedia Formats

• Format Sampling Rate
  Frequency Band
• Telephony 8 kHz
  200--3400 Hz
• Teleconference 16 kHz
  50--7000 Hz
• Compact Disk 44.1 kHz
  20-20000 Hz
• Digital Audio Tape 48 kHz
  20--20000 Hz
• CIF Video 3 Mpps
  36028830
• CCIR Video 12 Mpps 72057630
  
• HDTV 60 Mpps
  128072060
  
• mmc2.18

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Multimedia Compression Standards
NSA FS1015 2.4 kbps
speech LPC NSA FS 1016
4.8 kbps speech CELP CTIA IS-84
8.0 kbps speech VSELP GSM
13.2 kbps speech
RPE ITU G.72X, DECT, PHS 16,24,32,40
kbps speech ADPCM ITU G.721
64 kbps speech PCM ITU G.722
48,56,64 kbps audio
SB-ADPCM ISO JBIG
lt0.05gt bpp Fax AC ISO JPEGX
0.25-8 bpp Image DCT
ITU H.26X
p64kbps video MC-DCT ISO MPEGX
64-256kbps audio 16kbps-5Mbps
video mmc2.19