IPTV Video Quality: QoS & QoE

1 Executive Summary

1.1 Purpose

1.2 Situation

1.3 IPTV Observations Relating to Quality

1.4 Key Recommendations

2 Overview of Video and Video Quality

2.1 IPTV Market and Technology Situation

2.1.1 The Drive for Video Quality

2.1.2 Issues Interfering with Scaleable Deployment of IPTV

2.2 Video Content Challenges Are Increasing

2.3 Definitions: IPTV, Video Quality, Video Quality of Service and Quality of Experience

2.3.1 Video Quality (VQ)

2.3.2 Video Quality of Service (V-QoS)

2.3.3 Quality of Experience (QoE)

2.3.4 Non-Video Factors Affecting Quality of Experience

3 IPTV Architecture and Reference Model

3.1 IPTV Domains

3.2 End-to-End IPTV Ecosystem Architecture

3.3 ISO/OSI Communications Reference Model as Relates to IPTV

4 The IPTV Delivery Ecosystem and Video Quality

4.1 Content Development and Production Domain

4.2 Acquisition Domain

4.2.1 Characteristics of the Acquisition Domain

4.2.2 Types of Source Content

4.2.3 Variables that Affect Video Quality in the Acquisition Domain

4.3 Content Processing Domain

4.3.1 Characteristics of the Content Processing Domain

4.3.2 Video Encoding and Compression

4.3.3 Bandwidth Conservation Techniques Associated with Video Encoding

4.3.4 Variables that Affect Video Quality in the Content Processing Domain

4.4 Storage Domain

4.4.1 Characteristics of the Storage Domain

4.4.2 Variables Affecting Video Quality in the Storage Domain

4.5 Control Domain

4.5.1 Characteristics of the Control Domain

4.5.2 Variables Affecting Video Quality in the Control Domain

4.6 Distribution Domain

4.6.1 Characteristics of the Distribution Domain

4.6.2 Variables Affecting Video

4.7 Network Edge and Access Domain

4.7.1 Characteristics of the Network Edge and Access Domain

4.7.2 Variables Affecting Video Quality in the Edge and Access Domain

4.8 Customer Premises Domain

4.8.1 VQ and QoE Impact at the Customer Premises Domain

4.9 IPTV Concerns that Span Multiple Domains

4.9.1 Video Characteristics and Functionalities Occurring Across Multiple Domains

4.9.2 V-QoS and QoE Strategies and Techniques Used Across Multiple Domains

5 Test and Measurement for VQ, V-QoS and QoE

5.1 Video Quality Measurement

5.1.1 Video Signal Parameters

5.2 Transport and Video Quality-of-Service Measurements

5.3 Quality of Experience: Measurement of Interactivity

5.4 Quality of Experience: Holistic View

5.4.1 Comparing Video Input with Video Output

5.5 IPTV QoE: Qualitative and Perceptual Measurements

5.6 Test and Measurement Across the IPTV Ecosystem

6 Conclusions

6.1 Complex Ecosystem to Deliver MPEG-4 Video

6.2 Quality of Experience (QoE) is Both Measurable and Subjective

6.3 Data Errors Occurring in the Network Have Major Effect on V-QoS

6.4 The Choice of MPEG Transport Method Has an Effect on QoE

6.5 Standards for QoE

7 Recommendations for Maximizing Video Quality

7.1 Summary of Recommendations

7.2 Acquisition Recommendations

7.2.1 Be Prepared for Stringent Ingest Requirements From Video Programmers

7.2.2 Begin Testing Before the Encoder

7.2.3 Pre-Process Video Content into a Common Format

7.2.4 Digital Transport and Backhaul

7.3 Headend Design Recommendations

7.3.1 Establish the Video Service Lineup First

7.4 Video Encoding Recommendations

7.4.1 For Distribution, Encode to the MEG-4 AVC/H.264 Format

7.4.2 Establish Parameters for Video Content Errors

7.4.3 Carefully Evaluate the Options for Transcoding

7.4.4 Smoothing the Video Stream

7.5 Network Design Recommendations

7.5.1 Service Level Agreements

7.5.2 Design the Network to Accommodate HDTV, End-to-End

7.5.3 Establish Bandwidth Budgets

7.5.4 Remember to Budget for Non-Video Traffic

7.5.5 Additional Network Considerations that Impact VQ & V-QoS

7.6 Test and Measurement Recommendations

7.6.1 Deploy with a Full-Time Test and Measurement System

7.6.2 Recommended Placement of Test and Measurement Systems

7.6.3 Test for Impairments at the Physical Layer

7.6.4 Testing to Rigid Technical Standards is Not Enough

7.6.5 Perform Anecdotal Consumer Testing

7.7 CPE Recommendations

7.7.1 Operators Must Follow the STB Recommendations of Their Software Suppliers

7.7.2 Policy Management at the Set-top Box Level

7.7.3 Correcting MPEG Video Errors in the Set-top Box

7.7.4 Minimizing the Effect of Network Errors in the Set-top Box:

7.7.5 Network Termination Device

7.8 Quality of Service Recommendations

7.9 Quality of Experience Recommendations

7.9.1 Channel Change Times

7.9.2 Synchronization of Audio and Video

7.9.3 Prioritization of Service Traffic

7.9.4 MPEG Transport Streams

7.9.5 Implement Policies that Mitigate Network Issues Resulting from Oversubscription

7.9.6 Content Recommendations

7.10 Recommendations that Impact Multiple IPTV Domains

7.10.1 Implement Redundancy

7.10.2 Consider Established IPTV Architecture Reference Standards

7.10.3 Balance the Need for Standards Against the Virtues of Proprietary Solutions

8 Appendix 1: IP Communications Concepts Which Relate to Video Applications

8.1 ISO/OSI Basic Reference Model

8.2 IP Networking Standards

8.2.1 IGMP

8.2.2 RTSP

8.2.3 RTP

8.2.4 RTCP (Real-Time Transport Control Protocol)

8.2.5 UDP

9 Appendix 2: Video and Video Communications Standards

9.1 MPEG Video

9.1.1 MPEG Video Stream Structure

9.1.2 MPEG-2

9.1.3 MPEG-4

9.1.4 Other Video Standards

9.1.5 VC-1

9.1.6 MPEG-7 and MPEG-21

9.2 MPEG Transport

9.2.1 Approaches to MPEG Transport

9.2.2 Advocacy for MPEG-2 Transport

9.2.3 MPEG-2 Transport Steam Encapsulation

10 Appendix 5: IPTV Vendors

10.1 Video Networking Suppliers

10.2 Headend and Encoder Suppliers

10.3 IPTV Middleware Suppliers

10.4 Content Protection (Encryption, Watermarking) Suppliers

10.5 IPTV Network Suppliers

10.6 Test and Measurement

10.7 Professional Services

11 Appendix 6: Glossary of Terms

12 Index of Companies

Table of Figures

Figure 1-1: Domains Acquisition, Storage, Control and Distribution

Figure 1-2: Makeup of MPEG Video - Key to Controlling Packet Loss & Jitter

Figure 1-3: Comparison of MPEG-2 vs. MPEG-4 Video Quality

Figure 1-4: Comparing MPEG-2 and MPEG-4 Over DSL

Figure 1-5: Potential Sample Points Across The IPTV Ecosystem

Figure 3-1: Domains 1-5: Acquisition, Processing Storage, Control and Distribution

Figure 3-2: Domains 5-7: IPTV Distribution, Network Edge & Access and Customer Premises

Figure 3-3: IPTV Set-top Box Architectural Diagram

Figure 3-4: Hypothetical Tier-1 Operator with National (Super) Headend, Regional and Local Video Facilities

Figure 4-1: Example of Colors that are Outside of Established Color Parameters

Figure 4-2: Comparison of MPEG-2 vs. MPEG-4 Video Quality

Figure 4-3: Constant Bit-Rate Encoding

Figure 4-4: Illustration of How CF-CBR Limits Bandwidth Requirements

Figure 4-5: Aggregated Content Bundled Using CF-CBR

Figure 4-6: Embedding of Watermarks During Video Encoding

Figure 4-7: Application of Watermarks in the IPTV Ecosystem

Figure 4-8: Encrypted vs. Unencrypted Video

Figure 4-9: 1-D FEC Examples That Can Be Corrected

Figure 4-10: 1-D Example That Cannot Be Corrected

Figure 4-11: 2-D FEC Examples That Can Be Corrected

Figure 4-12: 2-D FEC Examples That Can Be Corrected

Figure 5-1: Holistic View of IPTV QoE

Figure 5-2: Potential Sample Points Across The IPTV Ecosystem

Figure 7-1: Comparing MPEG-2 and MPEG-4 Over DSL

Figure 7-2: Comparison of DSL Ability to Accommodate MPEG-2 and MPEG-4 Video

Figure 8-1: OSI ISO 7-Layer Basic Reference Model

Figure 9-1: Model for MPEG-2 Systems

Figure 9-2: Structure of MPEG Video

Figure 9-3: Data Loss Propagation in MPEG-2 Video Streams

Figure 9-4: Minimal MPEG-2 Transport Stream

Table of Tables

Table 3-1: Mapping the 7-Layer OSI Basic Reference Model to Video

Table 4-1: Home Network QoS Support

Table 8-1: ISO/OSI Model - Definitions and Functions of Each Layer In The Model