Adjusting Forward Error Correction with Quality Scaling for Streaming MPEG

1
Adjusting Forward Error Correction with Quality
Scaling for Streaming MPEG

• Huahui Wu, Mark Claypool, Robert Kinicki
• Computer Science,
• Worcester Polytechnic Institute

2
Outline

• Introduction ?
• Model Algorithm
• Experiments
• Conclusion

3
Introduction-Motivation
Video Frames
Forward Error Correction
4
Introduction-Overview
Video Quality
Optimal Point

• Adjusting FEC with Quality Scaling
• Given Network and Application Environment
• For each valid FEC and scaling combination
• Measure the video quality
• Find the optimal point

More FEC and More Scaling
5
Outline

• Introduction
• Model Algorithm?
• Experiments
• Conclusion

6
Algorithm

• Exhaustively search all FEC and Scaling
  combination and look for the optimal point
• For each FEC and Scaling combination
• S1 Estimate video frame sizes
• C Compute streaming bitrate and make sure its
  under capacity constraint
• S2 Estimate quality scaling distortion
• S3 Use frame sizes and FEC amounts to get
  successfully frame transmission rate
• S4 Compute playable frame rate
• S5 Compute overall video quality
• Measured by Distorted Playable Frame Rate

7
System Layers and Parameters
System Layers Parameters
Application
Presentation
Network
8
Video Frame Sizes S1

• Assumption 1 Video frame sizes vary
  exponentially with the quantization level

Frossard 01, Sakazawa 96

• Errors are less than half packet

9
Capacity Constraint C

• Total streaming bitrate
• where G is the constant GOP rate
• Should be no more than the capacity constraint T

10
Overall Video Quality S2S5

• Two distortion factors
• Quality Scaling
• Caused by a high quantization value
• Appears visually as coarse granularity in every
  single frame
• Measured by ITS-VQM Pinson 04
• Frame Loss
• Caused by network packet loss
• Appears jerkiness in the video playout
• Measured by Playable Frame Rate
• Overall Quality
• Distorted Playable Frame Rate

Wu 03 NOSSDAV
11
Distortion from Quality Scaling S2

• Assumption 2
• Quality scaling distortion varies exponentially
  with the quantization level

Frossard 01
12
Successfully Transmission Prob. S3

• Media-Independent FEC
• Reed-Solomon codes Reed 60

13
Playable Frame Rate S4

• Total Playable Frame Rate

Wu NOSSDAV03
14
Overall Quality S5

• Distorted Playable Frame Rate

The Operations Research Equation
15
Algorithm

• Exhaustly search all FEC and Scaling combination
  and look for the optimal point
• For each FEC and Scaling combination
• S1 Estimate video frame sizes (SI, SP, SB)
• C Compute streaming bitrate and make sure its
  under capacity constraint
• S2 Estimate quality scaling distortion (D)
• S3 Use frame sizes and FEC amount to get
  successfully frame transmission rate (qI, qP, qB)
• S4 Compute playable frame rate (R)
• S5 Compute distorted playable frame rate (RD)

16
Outline

• Introduction
• Background
• Model Algorithm
• Experiments ?
• Conclusion

17
Methodology

• Built a function RD()
• Returns the distorted playable frame rate
• Built an optimization program
• TCP-Friendly Bitrate Constraint
• Searches repair and scaling levels
• Returns the highest RD()
• Compared four FEC choices
• Non-FEC
• Small Fixed FEC
• Large Fixed FEC
• Adjusted FEC

18
System Setting
Network Layer Jaiswal 04 Network Layer Jaiswal 04 Application Layer Application Layer
tRTT 50 ms NP 4 frames per GOP
s 1 Kbyte NB 10 frames per GOP
p 0.01 to 0.04 RF 30 frames per sec

• GOP IBBPBBPBBPBBPBB

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Distorted Playable Frame Rate
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Conclusion

• Summary
• Analytically captures the frame dependencies
• Derives analytical models for streaming video
  with FEC and quality scaling
• Use OR algorithm to optimize the quality
• Future works
• Implementation
• Other quality scaling techniques (FGS)
• Quality scaling vs. temporal scaling

21
Adjusting FEC with Quality Scaling for Streaming
MPEG

• Huahui Wu, Mark Claypool, Robert Kinicki
• Computer Science, Worcester Polytechnic Institute
• http//www.cs.wpi.edu/claypool/papers/adaptive-fe
  c-qual/

Questions?
22
Outline

• Introduction
• Background ?
• Model
• Algorithm
• Experiments
• Conclusion

23
Video Compression Standard

• MPEG
• Popular compression standard
• Intra-compression and inter-compression
• Three types of frames I, P and B
• Group Of Pictures (GOP)

24
Quality Scaling

• Quality Scaling
• Adaptive Quantization Level

• 24KB, 10KB, 5KB

25
Forward Error Correction (FEC)

• Media-Independent FEC
• Reed-Solomon codes Reed 60

26
Capacity Constraint

• TCP-Friendly Flow Padhye 00
• Bottleneck Capacity
• Dial up 56 Kbps
• DSL 1.5 Mbps (Verizon)
• Cable Modem 3 Mbps/384 Kbps (Charter)
• Video is often larger than 1.5 Mbps

27
Playable Frame Rate S4

• Playable Frame Rate (PFR) of I frames

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Playable Frame Rate S4 (cont.)

• PFR of P frames

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Playable Frame Rate S4 (cont.)

• PFR of B frames

30
How RD works
Repair Method D R RD Q (user)
QAFEC 0.17 28.55 23.78 6.89
SFEC 0.20 23.58 18.90 4.44
LFEC 0.44 30.00 16.93 3.89
NFEC 0.28 20.17 14.61 3.50
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Distorted Playable Frame Rate
32
Introduction-Motivation
Video Frames
Forward Error Correction
33
Successfully Transmission Prob. S3

• Media-Independent FEC
• Reed-Solomon codes Reed 60