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Video Quality and MPEG Transmission Systems

Video Quality and MPEG Transmission Systems. Presented by Steve Holmes. Agenda. QOS and QOE. MPEG over IP. Real Time Video Quality Analysis. MPEG Transport Stream Analysis. 2. Picture Quality in the Compressed World / What is your Dial Norm. Quality of Service QOS

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Video Quality and MPEG Transmission Systems

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  1. Video QualityandMPEG Transmission Systems Presented by Steve Holmes

  2. Agenda QOS and QOE MPEG over IP Real Time Video Quality Analysis MPEG Transport Stream Analysis 2

  3. Picture Quality in the Compressed World / What is your Dial Norm Quality of Service QOS Quality Of Experience QOE

  4. Most Broadcasts Before DTV Transition HD Color Space HD Server SD Server Television Broadcaster SD Color Space

  5. Post DTV Transition Broadcast HD Color Space HD Server 405 Television Broadcaster SD Color Space from HD

  6. Most CATV Pre-transition HD Color Space HD Server CATV Provider SD Server Television Broadcaster SD Color Space

  7. Post DTV Transition CATV Down Converter HD Server Television Broadcaster CATV Provider One TV program going to two different TV services What color space do you protect for

  8. Satellite MPEG 4 (h.264) Feed, MPEG 2 distribution Quality of Service Quality of Experience Transmission Path h.264 Feed Signal Process (rate shape) Where do you measure What do you measure Transcode to MPEG2 Maybe down convert to SD?

  9. Signal source Monitor the Signal Processing Monitor the Camera’s output Up-Link Signal Processing Camera

  10. Picture Quality AnalysisVQS1000 Single ended (feature extraction) Picture Quality Analysis

  11. VQS1000 Quality analysis • Single ended QoE analysis of video and audio content. • Enables operators to see impairments and artifacts in the Picture • Unique visualization tool with innovative impairment displays highlights the location and severity of video defects,

  12. QOS Analysis with the VQS1000 VQS1000 Transcoders, Encoders, Down Converters Reference and Test Based Human Vision Modeling Signal Process (rate shape)

  13. VQS1000 • Three Applications • Designed for use with all current Tektronix DTV monitor configurations using private backhaul video • Stand alone – real time connected to switch or router (IGMP) • Stand alone - for offline file analysis • Reliable algorithms to de-coded MPEG-2 or H.264 video • Industry First unique visualization tool with innovative impairment displays • Triggered-capture of streams • Logging of live data • Full integration with Tektronix IP Video and DTV Monitoring Probes

  14. VQS1000 QoE Trend Graph Metdata QoE Dashboard QoE Visualisation Area of interest

  15. VQS1000 started from MPEG analyzers Play Icon to launch VQS1000

  16. Monitoring MPEGTransport Streams

  17. IP/UDP/ RTP MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes MPEG Video Packet 188 or 204 bytes What is Real-time Streaming Video over IP? • Video over IP is a new technology that uses Internet Protocol (IP) packets to carry video content from one location to another over a switched network • Packets are grouped, tagged, switched and “consumed” at the end-point • This is often referred to as “streaming video over IP” • MPEG over IP • MPEG-2, MPEG-4 • Other video over IP • PES over IP and Microsoft Media 9 over IP IP IP packet with MPEG video payload carried over Ethernet Could have additional protocols such as RTP Ethernet CRC 1362 bytes We are not talking about File transfers We are talking about Real-Time live MPEG over IP rather than ASI for example.

  18. Rate 3.75Mb/s Rate 3.75Mb/s Rate 3.75Mb/s Low-Jitter on Video over IP • Bit rate everywhere = 3.75 Mb/s • Maximum buffer size needed = 1 IP transport packet (1316 bytes) • Zero Media (Packet) loss • 3.5 ms of delay required to subtract the jitter and 0 media loss IP packets carrying video Perfect Stream Time

  19. High-Jitter on Video over IP • Maximum buffer size needed = 1 Mbit at 3.75Mbits/s • 267ms of delay required to subtract the jitter • Conventional Ethernet Jitter = +-100us • Meaningless for video applications 1 Mb of Overflow 1 Mb of Underflow Rate = 4.75Mb/s Rate = 3.42Mb/s Time Same stream with Ethernet Jitter Stream 1 Second 3 Second

  20. No Errors Slice Error B I B B B B B B P B P B B P B P B The impact of packet loss • No TR 101 290 errors • No Buffer Over or Under flows • No Video errors • Dropped I-Frame is catastrophic • Blocking will continue until next I-Frame in a new Group Of Pictures(GOP) or dynamicscene change • MPEG-4/AVC can make the problem worse • One dropped IP Packet equals 7 dropped Transport Stream packets • Leads to: • Slice errors • Macro blocking • PCR errors • Loss of sync Major Errors Caused By Corruption of Following I-Frame

  21. Rate is determined by the MPEG Example 4.5Mb/s Each Ethernet packet contains up to 7 MPEG packets Rate is determined by the MPEG Example 4.5Mb/s Perfect Streaming Video (Theoretical) Ethernet Inter-Packet Gap MPEG Packets MPEG Inter-Packet Gap Ethernet Packets What great Video Buffer (Removes Ethernet frame and buffers MPEG) Decoder Monitor, TV, etc

  22. GigE PIT (Packet Intearrival Time) PIT shows the buffer usage that is need to Un-pack the IP packets at the receive end of an IP network

  23. Streaming Video Large Inter-packet Gap Ethernet Inter-Packet Gap MPEG Packets MPEG Inter-Packet Gap What great Video Ouch what was that Buffer (Removes Ethernet frame and buffers MPEG) Decoder Monitor, TV, etc

  24. GigE PIT with too much packet delay Ethernet Inter-Packet Gap Larger than your Buffer No MPEG Packets Buffer (Removes Ethernet frame and buffers MPEG)

  25. Streaming Video Large Inter-packet Gap Buffer Over-Run Monitor, TV, etc IP Small Inter-Packet Gap MPEG Packets MPEG Inter-Packet Gap Buffer (Removes Ethernet frame and buffers MPEG) Decoder

  26. Ethernet Transport Dropped Packet Switch

  27. Cross Layer Analysis PCR and PIT

  28. Network Monitoring Audio & Video Quality MPEG Transport IP Network 3 levels of digital video monitoring Supporting Protocol Specifications Video: MPEG 2, H.264/AVC & VC-1, & decodes MPEG-PSI, DVB-SI & ATSC-PSIP table support, SNMP % MIB support Audio: Dolby AC-3 (5.1 surround), MPEG-1 Layer II, (mono, stereo), AAC Carousel: EBIF, tru2way, BFS, MHP/DSM-CC Digital Program Insertion: SCTE-35 (local ads) • Software-driven solution • Single box composed of: • Flexible multiple multi-core processing • Easy set-up for customer • Centrally controlled from single GUI

  29. Video & Audio QoE • Reflects the overall subscriber TV viewing & audio experience • Scores subscriber impacting events independently from continuity counter errors, network jitter or TR 101-290 • Automatically & continuously evaluates all video programs in real time • 60-day historical graphing with real time alerting capability

  30. Video QoE Below 75 Screen capture of a video clip causing VQoE drop below 75 without continuity counter errors* * Depending on monitoring location, network and equipment

  31. IP Monitoring IP network monitoring: Packet arrival rate Delay factor Full alerting capability Historical bandwidth & IP graphing Root cause analysis to determine whether problem is video or IP related

  32. MPEG TR101-290(ETR290)Monitoring

  33. Testing to Measurement Guidelines • When you test something you need to have a Standard or Guideline to test to. • The Measurement Guidelines we test to is known as ETSI TR 101 290. Digital Video Broadcasting (DVB); Measurement guidelines for DVB systems, or AKA TR101-290 • TR101-290 Tests are broken into 3 Priorities • First priority: Sync, PAT & PMT, Continuity ….. • Second priority: PCR’s, CRC’s, RF FEC • Third priority: EPG

  34. MPEG Tables

  35. TR101-290 & ATSC test Recommendations • Baseband measurements split into 3 groups • 1st priority • Required for Decode ability • Basic Monitoring • 2nd priority • Recommended monitoring • Program Decodeability • 3rd priority • Application Dependant – PSIP • May cause a decoder from finding a service • ATSC Error Characterization • Transport Stream Off Air (TOA) • Program Off Air (POA) • Component Missing (CM) • Quality Of Service (QOS) • Technically Non-Conformant (TNC)

  36. TR101-290 1st Priority No:Indicator 1.1 *TS_sync_loss 1.2 *Sync_byte_error 1.3 + PAT_error 1.4 *Continuity_count_error 1.5 +PMT_error 1.6 +PID_error * Transmission Monitoring + Encoder Monitoring

  37. TR101-290 2nd Priority No:Indicator 2.1 # Transport_error 2.2 * CRC_error 2.3 *+ PCR_error 2.4 *+ PCR_accuracy_error 2.5 + PTS_error 2.6 + CAT_error * Transmission Monitoring + Encoder Monitoring # RF FEC overflow Monitoring

  38. TR101- 290 3rd Priority – DVB / ATSC Indicator DVBATSC PSIP_Error MGT_Rate STT_Rate RRT_Rate EIT_Rate VCT_Rate NIT_error SI_repetition_error Unreferenced_PID SDT_error EIT_error TDT_error RST_error EPG Data inserter Monitoring

  39. Key Monitoring and Test challenges • What makes the phone ring • Loss of signal • Loss of a program • Picture breaking up • Audio breakup • Not a PMT being 20ms over the limit • When monitoring MPEG it’s some what like monitoring Video, everything is not Black & White. We do not reject video that is at 101IRE instead of 100IRE. The same goes for MPEG monitoring some things can be tolerated and some can not. The Key is to know the difference and what can show up in the picture. • MPEG monitoring falls into two categories. • Things that are Binary (Good/Bad) • Things that have acceptable working windows of operation • Looking at the network only does not catch the errors • Your customers are not looking at the network that are watching Video that comes from the MPEG stream. You have to Monitor the MPEG layer as well as the Network Layer. • The key is knowing who does what and how far can it go.

  40. Key Monitoring and Test challenges • Binary alarms • Are things that must be in the stream for proper operation. Things like; • The sync byte • Sync byte error • Continuity counter • Transport Error Flag • Any MPEG2 table missing for more than 1 second • If any of these are missing or incorrect the Transport stream will have major errors

  41. Key Monitoring and Test challenges • Adjustable alarms • Are thing like how often a particular table arrives. The timing swing of the PCR. • PAT timing MPEG2/ ATSC Limits 100 ms or less • up to 500 ms should not cause a program issue* • PMT timing MPEG2/ ATSC Limits 400 ms or less • up to 2000 ms should not cause a program issue* • PCR timing MPEG2/ ATSC Limits 100 ms or less • up to 500 ms should not cause a program issue* • PTS timing MPEG2/ ATSC Limits 700 ms or less • up to 3500 ms should not cause a program issue* • PCR Jitter Frequency errors • PCR inaccuracy MPEG2/ATSC Limits +/– 500 ns or less • up to +/- 2500 ns should not cause a program issue* ** • PCR overall jitter MPEG2/ATSC Limits +/-25 μs or less • up to +/-125 μs should not cause a program issue* * Per A78 ATSC Recommended Practice: Transport Stream Verification

  42. GigE Physical Layer

  43. Encoder Encoder Video on Demand Server CATV Monitoring Points in Network Home Headend Sub Headend Set-top with IP address Rate Shaper Analog ASI to IP ASI Satellite Video Feed Aggregation Switch Aggregation Switch QAMs 10 gig Network Ring Analog ASI Direct Video Feed Sentry Edge Sentry IP Sentry IP & ASI Web User Medius Consul NOC Monitor

  44. Encoder Encoder Video on Demand Server Monitoring Points in Network Home Headend Sub Headend Set-top with IP address Rate Shaper 8 6 1 Analog ASI to IP ASI Satellite Video Feed Aggregation Switch Aggregation Switch QAMs 10 gig Network Ring Analog ASI Direct Video Feed MTM400 MTM400 MTM400 Web User SNMP NOC Monitor

  45. Broadcast Network Monitoring Points 8 VSB Mod 8 VSB PA Network STL Encoder Source Mux Monitoring here gives you a look at the input to the STL MTM400 MTM400 Analog or SDI (WFM7120), and Picture Quality Monitoring Test Point 8VSB RF Transmission Testing Protocol Analysis of MPEG-2 Transport Stream and associated DVB or ATSC tables MTM400 Monitoring here gives you a at the output of the STL or the RF power tap MTM400 Monitoring here gives you a end to end view of your network

  46. Network Monitoring Via RF MTM400 8 VSB Mod 8 VSB PA Network STL Encoder Source Mux PSIP Analog or SDI (WFM7120), and Picture Quality Monitoring Test Point MTM400 Demo

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