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ARMOR- A djusting R epair and M edia Scaling with O perations R esearch for Streaming Video. PhD Candidate: Huahui Wu - Computer Science, Worcester Poly. Inst. Committee: Prof. Mark Claypool - Computer Science, Worcester Poly. Inst.
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ARMOR-Adjusting Repair and Media Scaling with Operations Research for Streaming Video PhD Candidate: Huahui Wu - Computer Science, Worcester Poly. Inst. Committee: Prof. Mark Claypool - Computer Science, Worcester Poly. Inst. Prof. Robert Kinicki - Computer Science, Worcester Poly. Inst. Prof. Craig Wills - Computer Science, Worcester Poly. Inst. Prof. Wu-chi Feng – Computer Science, Portland Stat Univ.
Acknowledge • Prof. Claypool and Prof. Kinicki • Prof. Wills • Prof. Wu-Chi Feng from Portland State Univ. • Faculty/Staff of Computer Science Dept., WPI • Jae Chung, Feng Li, Mingzhe Li and Rui Lu • User study participants • Attendees today • My Family Ph.D. Defense
Introduction - Motivation Video Frames Repair by Forward Error Correction (FEC) Ph.D. Defense
Adjusting Repair and Media Scaling Given Network and Application Environment For each valid FEC and scaling combination, measure the video quality Find the optimal point Operations Research Concept Optimal Point Video Quality More Repair and More Scaling Ph.D. Defense
The Dissertation M A S I M A U M A U S M A M A M: Video Quality Model A: Optimization Algorithm U: User Study S: Simulation I: Implementation Ph.D. Defense
Outline • Introduction • Background • Models • Algorithms • User Study • Implementation • Contributions • Conclusions Ph.D. Defense
Video Compression Standard • MPEG • Popular compression standard • Intra-compression and inter-compression • Three types of frames: I, P and B • Group Of Pictures (GOP) • ARMOR models MPEG dependencies Ph.D. Defense
Forward Error Correction (FEC) • Media-Independent FEC • Reed-Solomon codes [Reed+ 60] • ARMOR models benefits of FEC for frame transmission Ph.D. Defense
Media Scaling • Sacrifice data to fit the capacity • Temporal Scaling (TS) • Pre-Encoding Temporal Scaling • Post-encoding Temporal Scaling Ph.D. Defense
Media Scaling (cont.) • Quality Scaling • MPEG uses quantization in coding to save bits • Quantization Value (1~31) • For example: original data = 23, 13, 7, 3 • ARMOR models both Temporal Scaling and Quality Scaling Ph.D. Defense
Video Quality Measurements • Subjective Measurement • User study, expensive, not practical • Objective Measurements • Playable Frame Rate (R) • Good for Temporal Scaling, not for Quality Scaling • Peak Signal Noise Ratio (PSNR) • Good for Quality Scaling, not for Temporal Scaling • Video Quality Metric (VQM) [Pinson+ 04] • By Institute for Telecommunication science • Extracts 7 perception-based features • Only one for frame losses • Report a distortion value from 0 (no distortion) to 1 (many) • ARMOR uses both R and VQM • A comprehensive user study is included Ph.D. Defense
Outline • Introduction • Background • Models • Streaming Bitrate Model (cost) • Video Quality Model (benefit) • Algorithms • User Study • Implementation • Contributions • Conclusions Ph.D. Defense
Parameters and Variables Video Frames Repair by Forward Error Correction (FEC) Ph.D. Defense
Streaming Bitrate Model • Total streaming bitrate, including video packets and FEC packets: where G is the constant GOP rate NPD and NBD are the numbers of transmitting P and B frames depending on Temporal Scaling level lTS Ph.D. Defense
Video Quality Model - Overview • Two distortion factors • Frame Loss • Caused by Temporal Scaling and network packet loss • Appears jerky in the video playout • Measured by Playable Frame Rate • Quantization Distortion • Caused by a high quantization value with Quality Scaling • Appears visually as coarse granularity in every frame • Measured by VQM • Overall Quality • Distorted Playable Frame Rate [Wu+ 05 TOMCCAP] Ph.D. Defense
Playable Frame Rate (R) • Frame Successful Transmission Probability • Where Frame Size • Frame Dependencies • Total Playable Frame Rate Ph.D. Defense
Distorted Playable Frame Rate (RD ) • Quality scaling distortion varies exponentially with the quantization level • Distorted Playable Frame Rate [Frossard+ 01] Ph.D. Defense
ARMOR Algorithm • For each Repair and Scaling combination • Estimate video frame sizes (SI, SP, SB) • Compute streaming bitrate B and make sure it’s under capacity constraint T • Use frame sizes and FEC amount to get successfully frame transmission rate (qI, qP, qB) • Compute playable frame rate (R) • Estimate quality scaling distortion (D) • Compute distorted playable frame rate (RD) • Exhaustively search all FEC and Scaling combination and look for the optimal quality Ph.D. Defense
Outline • Introduction • Background • Models • Algorithms • User Study • Implementation • Contributions • Conclusions Ph.D. Defense
User Study Goals • Accuracy of RD • Correlation with user perceptual quality • Versus PSNR and VQM? • Temporal Scaling versus Quality Scaling • What are the differences? • Adjusted Repair (FEC) versus No Repair • Is Adjusted Repair an effective method for increasing perceptual quality? Ph.D. Defense
Video Clips • Compare degraded clips to the original • Original: 30 fps, no quality scaling • Degraded: Combinations of 4 independent factors (2 options each) • Video and Network environment • Video content: low motion (News) or high motion (Coastguard) • Packet loss rate: low loss (1%)or high loss (4%) • ARMOR Layer • Repair: adjusted repair or no repair • Scaling: Quality Scaling or Temporal Scaling • 24=16 combinations for evaluation Ph.D. Defense
User Study Application 54321 • Two-week volunteer study • 74 users, most CS undergraduate students [ITU-R BT.500-11] Ph.D. Defense
Results – Video Quality Metrics (1) Same as original clip User Score versus PSNR Much worse than original clip Ph.D. Defense
Results – Video Quality Metrics (2) User Score versus VQM Score (1 – VQM distortion) Ph.D. Defense
Results – Video Quality Metrics (3) User Score versus Distorted Playable Frame Rate (RD) Ph.D. Defense
Results – Scaling Methods RD 30.0 22.5 15.0 7.5 0.0 Temporal Scaling versus Quality Scaling ARMOR Prediction (Coastguard) User Score Ph.D. Defense
Results – Repair Methods RD 30.0 22.5 15.0 7.5 0.0 Adjusted Repair versus No Repair User Score ARMOR Prediction (Coastguard) Ph.D. Defense
Outline • Introduction • Background • Models • Algorithms • User Study • Implementation • Contributions • Conclusions Ph.D. Defense
Architecture 3 3 2 2 1 2 3 4 1 8 7 6 5 Ph.D. Defense
Experiment Settings • Video clip Paris • medium motion and details • two people sitting, talking, with high-motion gestures • 1200 CIF (352x288) images • average I / P / B frame sizes: 24.24KB / 5.20 KB / 1.18 KB Ph.D. Defense
Results RD RD ARMOR Analytical Results ARMOR Measurement Results Ph.D. Defense
Contributions • Derived a novel video quality metric • Distorted playable frame rate • Family of Video Quality Models with Repair and Scaling • Modeled the playable frames rate • Modeled quantization distortion • Studied four ARMOR variants: • Media Independent FEC with Temporal Scaling • Media Independent FEC with Quality Scaling • Media Independent FEC with Temporal Scaling and Quality Scaling • Media Dependent FEC with Quality Scaling • Derived optimization algorithm to maximize the quality of streaming video • Conducted a comprehensive user study • Presented the high correlation between user score and distorted playable frame rate • Implemented a working ARMOR system Ph.D. Defense
Conclusions • Distorted playable frame rate has a high correlation with user perceptual quality • Higher than PSNR or VQM • Adjusting repair improves video streaming quality significantly • Better than fixed repair and no repair • Quality Scaling is more effective than Temporal Scaling • But when bandwidth is low and network loss is high, Quality Scaling should be used with Temporal Scaling • Media Dependent FEC is not as effective as Media Independent FEC • ARMOR can be implemented in a real video streaming system and effectively improve streaming quality Ph.D. Defense
ARMOR-Adjusting Repair and Media Scaling with Operations Research for Streaming Video PhD Candidate: Huahui Wu - Computer Science, Worcester Poly. Inst. Committee: Prof. Mark Claypool - Computer Science, Worcester Poly. Inst. Prof. Robert Kinicki - Computer Science, Worcester Poly. Inst. Prof. Craig Wills - Computer Science, Worcester Poly. Inst. Prof. Wu-chi Feng – Computer Science, Portland Stat Univ. Questions?
Future Work • Study of Variance of Playable Frame Rate • Study of dynamic Group of Pictures • Study of different quantization values for different types of frames • Implementation of MIQS and MITQS systems • Study of other scaling methods • User study of more videos Ph.D. Defense
Playable Frame Rate [S4] • Playable Frame Rate (PFR) of I frames Ph.D. Defense
Playable Frame Rate [S4] (cont.) • PFR of P frames Ph.D. Defense
Playable Frame Rate [S4] (cont.) • PFR of B frames Ph.D. Defense
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 Ph.D. Defense
Results – Video Quality Metrics (2) User Score versus Playable Frame Rate (R) Ph.D. Defense
Lines of Codes Ph.D. Defense
Related Work • DAVE (Delivery of Adaptive Video) • Describes video content • Supports physical and semantic adaptation • Does not consider capacity constraint and media repair • Priority Drop • Implemented SPEG for media scaling • Uses TCP as transmission protocol Ph.D. Defense
Media Scaling (cont.) • Quality Scaling (QS) • Adaptive Quantization Level • 24KB, 10KB, 5KB Ph.D. Defense
System Layers and Parameters Ph.D. Defense