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IP Video Quality Testing

IP Video Quality Testing. Oct 2008. Agenda. Video Networks IP Video QoS QoS and QoE mapping vs Network Segments IPTV testing Trouble-shooting Noise Analysis Summary. Service Delivery. ONT : Optical Network Terminal ONU : Optical Network Unit OLT: Optical Line Terminal

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IP Video Quality Testing

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  1. IP Video Quality Testing Oct 2008

  2. Agenda • Video Networks • IP Video QoS • QoS and QoE mapping vs Network Segments • IPTV testing • Trouble-shooting • Noise Analysis • Summary

  3. Service Delivery ONT: Optical Network Terminal ONU: Optical Network Unit OLT: Optical Line Terminal RG: Residential Gateway VOD: Video On Demand IAD: Integrated Access Device

  4. Triple Play Network/Service Challenges • Video Hub Head End • Poor content quality from content provider. • PCR Jitter from encoder, splicer or VOD source. • PID mappings or data table mappings from video source • Proper Trans-coding • 15-20% of Problems Complex Network Environments require Service Assurance Systems to minimize expensive dispatches • Signaling and Media Gateways • Mis-provisioning creates incorrectly routed calls • Signaling translations and incompatibilities. • Echo Canceller configurations • IGMP and RTSP Latency • Core Ntwk • Mistakes here catastrophic • Misprovisioned tributaries and routes • Routing/Link over utilization….poor traffic engineering. • Poor circuit routing…..creates excessive delays • Last Mile • Signal degradation. • Impulse noise • Copper pair: imbalanced lines, • Bridge taps, etc. • Data applications don’t experience these problems because of TCP. • Voice and video experiences issues because of real-time nature. 25% of Problems • Cust Prem • Customer Data Traffic victimizes VoIP/Video • Misconfigured Premise Equipment • Firewalls • Inside wiring Cat 3, Coax • In-home Networking, HPNA, MoCA, Wireless, BPL 50% of Problems Head End Hub Office VoD D/A POTS IP MPLS/ ATM Core Eth Aggr Network Splitter RG STB TV GbE GbE GbE TV LOCAL ADS & CONTENT DVB DEMUX RF xDSL QT-600 QT-600 PC QT-1100 QT-1100 QT-1100 QT-200 HST-3000 NetComplete 5-10% of Problems

  5. Service Provisioning IGMP Latency RTSP Latency QoS and QoE mapping for Video Services Video QoS QoE Parameters Video QoS parts Picture: blocking, blurring, edge distortion, visual noise Audio: Lip sync, drop outs V-MOS Error Indicator Count Content Quality IP Packet Loss Transport Quality IP Packet Jitter RTP Packet Loss Video Stream Quality RTP Packet Jitter Pixelization, tiling frame freezes, Blue screen TCP Re-transmissions Transaction Quality Continuity Error PCR Jitter PSI Table Data (Error) Service accessibility, Channel Change latency Pause, Play Latency Note 1: requires payload decode analysis

  6. Transaction Quality Transaction Quality Transaction Quality IP Video Network Segment Test Focus-Broadcast HE QoS Network QoS Access QoS Total QoS @ STB Content Quality Local Content Insertion Content Quality Video Stream Quality Video Stream Quality Video Stream Quality Video Stream Quality Transport Quality Transport Quality Transport Quality PCR Jitter, PSI Data, Error Ind, Compression – GOP, Type of Coder, Bit Rate, Profile PCR Jitter Packet Loss Packet, Jitter IGMP Latency, PCR Jitter, PSI data, Error Ind, BW, MPEG-TS Pkt Loss, Jitter, Period, Distance, MOS Distance, Period

  7. Total QoS @ STB Hub Office QoS Network QoS Access QoS Content Quality Content Quality Video Stream Quality Video Stream Quality Video Stream Quality Video Stream Quality Transport Quality Transport Quality Transport Quality Transaction Quality Transaction Quality PCR Jitter, PSI Data, Compression (GOP, Type of Coder, Bit Rate, Profiles), Trick Play Latency RTSP (Trick) Latency, PCR Jitter, PSI data,, BW, MPEG-TS Pkt Loss, Jitter, Period, Distance, MOS PCR Jitter Packet Loss Packet Jitter Distance, Period IP Video Network Segment Test Focus-VOD

  8. IP TV Installation DSLAM • Test Set • STB/Modem emulation • IP Video QoS check • Broadcast & VOD MDF Gathering Network (IP) Core Network (ATM, IP) STB ATU-R TV Program Broadcaster TV Program Providers IGMP signal IP Video Service Platform Local Content Added Network Specific Thresholds

  9. 1 1 xDSL Verification TE Replacement xTU-C Replacement ISP ATM/IP xTU-R Replacement DSLAM IP Routing RAS • Focus on showing end service functionality • Connectivity to the DSLAM • Connectivity to ATM network • Connectivity to IP network and beyond

  10. Video QoS – Network Specific Thresholds Thresholds can be set in the HST for Pass, Fail, Marginal The QoS screen shows the critical quality parameters for a video flow: PCR jitter measures this key parameter; if high the decoder can not properly decode the video payload: Pass < 100 mS Latency is the IGMP latency, the time to change channels for Broadcast Video: time from IGMP request to Rx of first video packet: <200 mS Cont. Err is the analysis of video Transport Stream packets which show the Continuity Error indicator set which = lost packet events: < 0.1% If Error Indicator count = >0 then content problem If all items = Pass, no further analysis necessary by field tech.

  11. MPEG over Ethernet Transmission issues 1) Perfect Video Stream Inter Frame delay OK typically 2-4 ms STB Buffer MPEG Decoder Video rate  i.e 3 Mbps 3 Mbps 2) Stream with jitter or rate under run Inter Frame delay to long TV Buffer underflows 3) Stream with jitter and/or rate over run Inter Frame delay to short Buffer overflows Drop Packet Ethernet packet  contains up to 7 MPEG packets MPEG packet  188 Bytes

  12. IP Video Testing Critical Diagnostic Fault Conditions: • Video impairments • All channels? • One channel? • Time of day specific • A pattern? • Random throughout the day? • Temporal component • Bursts? • Randomly spaced?

  13. IP Video Testing IP Fault Resolution: Step #1 • Video pixelizations • All channels? = yes • Lost packet events will be seen on more than one stream • Lost packets • Analyze physical layer stats • Ethernet I/F stats • ATM stats • DSL stats • Sectionalization • If no errors are seen at the physical layer of both I/F ‘s, then packet loss is up-stream of the DSLAM

  14. IP Video Testing IP Fault Resolution: Step #2 • Video pixelizations • Physical layer problems? = yes • Check DSL stats for errors • If yes, impulse noise most likely cause, if noise margin at least 6 dB. • Review Bits/Tone graphs for notches • Notches = Noise problems • Check packet layer stats • If CRC errors = loop noise problems • If Length errors, but no CRC then may be network QoS /Buffer over flow issues, not loop noise problems • If both most likely loop noise issues Evaluate copper loop for narrow band and wide band issues. Use temporal input to pinpoint sources.

  15. IP Video Testing IP Fault Resolution: Step #2 • Video pixelizations • Physical layer problems? = yes • Check VDSL stats for errors • FEC errors: Un-correctable FEC errors • If yes, impulse noise most likely cause, if noise margin at least 6 dB. • Review Bits/Tone graphs for notches • Notches = Noise problems • Check Packet stats • RTP Stats • RFC 3357 • MDI • If both most likely loop noise issues Evaluate copper loop for narrow band and wide band issues. Use temporal input to pinpoint sources.

  16. IP Video Testing IP Fault Resolution: Step #3 • Video pixelizations • All channels? = no • Lost packets • Analyze lost packet stats • Typically none seen when trouble is one ch. • Analyze PCR jitter stats • PCR jitter problems are typically source issues: • Head End trans-coding problems • Local Ad insertion problems • Analyze PSI Error stats • Typically a content issue • Error Indicator Count • Analyze count • Corrupted content leaving the encoder Yes No

  17. IP Video Testing IP Fault Resolution: Step #3 • Analyze PCR jitter stats • PCR jitter problems are typically source issues: • Head End trans-coding problems • Local Ad insertion problems • Report PCR Jitter stats with Time-of-Day, and Channel or Program ID • PSI table data analysis • PAT and PMT data present • Present • Present at or above a threshold rate, typically every half second, but in MSTV network usually only every second or 1.5 seconds For each video program stream the PID’s (Packet Identifiers) are shown for each piece: Video, Audio, & PSI table data. The Type and Description data is decoded from the stream as received. Unknown data includes data not included in the other categories such a Fill/PAD data or data marked as “reserved”.

  18. Impulse Noise Standards Definition • VDSL is more susceptible to impulse noise events due to it’s use of a wider frequency spectrum than ADSL. Noise sources are being analyzed in several forms: • REIN (Repetitive Electrical Impulse Noise) • Less than 1 ms in duration • No bit errors desired • INP mitigation • PEIN (Prolonged Electrical Impulse Noise) • 1 to 10 ms in duration • No bit errors desired • INP mitigation • SHINE (Single Isolated Impulse Noise Event) • Duration greater than 10 ms • Due to duration, bit errors will typically occur • No loss of sync is desired

  19. Impulse Noise Analysis Sources of Impulse Noise • Central heating/air - switch on/off • A neighbour’s Jacuzzi (Motor) • Television sets • Video recorders • PC scanner • Faulty street lights. • Faulty Metal Halide lighting • Faulty fluorescent lighting • External Hi/Lo Security Lights • External low voltage lights • Seasonal Lights • Satellite Receiver • AC Power faults near copper loops 00:00:06 5 15 Impulse count with 3dB below and above threshold 15 Proper Filter Event capture

  20. Spectral Noise Analysis Wider VDSL spectrum opens loop to new noise sources Up to 5 MHz Max Hold shows transient peak values Up to 15 MHz Up to 30 MHz Spectral noise analysis down to -145 dBm/Hz

  21. HPNA/VDSL in Home – VDSL2/Cu Noise/TDR HST as a troubleshooting tool • HST connects to TWP or Coax, HPNA or VDSL • Syncs to VDSL2, monitors copper, TDR analysis • Monitors 0-30MHz spectral analysis: Transient and Impulse noise • Interactive or long term monitoring 0-30MHz Copper Noise CPE VDSL2 Sync Analysis HST-3000 STB TWP SAI VDSL Coax Adapt Splitter IP DSLAM B-Box / SAI

  22. IP Video Testing IP Fault Resolution: Step #4 • Excessive IGMP Latency • All channels? = no • Report as program source issue • All channels? = yes • Analyze time of day issues • Random or a pattern • Report issues • Review: • Review IGMP snooping hierarchy • Review traffic loading, special event issues • Multi-cast flows, are all channels available at DSLAM • Temporal caching plan impacts MDF Gathering Network (IP) Core Network (ATM, IP) DSLAM STB ATU-R IGMP signal IP Multi-cast Platform

  23. Video QoS – Packet Loss Correlation IP Fault Resolution: Step #5 The Pkt Loss screen shows the status of the physical layer: ATM and DSL layer measures provide insight into the ADSL loop performance: Errors here indicate packet loss may be due to loop problems. If no errors are seen on the access loop, then packet loss is North-bound of the DSLAM (in the network). If no errors, then problems are typically in the network.

  24. Video QoS Bandwidth & Pkt. Analysis IP Fault Resolution: Step #6 Individual bit rates are shown for each portion of the video stream. Unknown data defined as any data, such as PAD bits to maintain a constant data rate, or private IP data over MPEG, that is detected is also shown. Packet stats parameters are measured at the IP layer. IGMP Latency is the measure of the network components to complete a program change, i.e. changing the channel in Broadcast video.

  25. MOS Score Evaluation IP Fault Resolution: Step #7 MOS score analysis for video and audio portions: Video factor is like audio R-Factor showing a score built from network elements of the factors effecting the MOS score . The same analysis is provided for the audio portion of the program.

  26. PID Map & Combined Stream Data IP Fault Resolution: Step #8 Totals for up to 3 streams: Combined total data rate for the streams under analysis, in this case 3. Simultaneous analysis of multiple streams is helpful in locating problem sources.

  27. IPTV troubleshootingPutting Physical Analysis Together ADSL tests Passed Copper tests Failed (impulsive noise, spectral) Copper tests Passed ADSL tests Failed (ADSL errors within UP stream) Copper tests Failed (impulsive noise, spectral) Distributionbox ADSL Example: Not twisted Not shielded pair DSLAM Street cabinet MDF ADSL2+ modem NID 18 m 1330 m 280 m

  28. IP Video Testing Focus Summary • Video Services (Broadcast & VOD ) Verification and Quality analysis at the VideoPacket Level and the Transport Stream (RTP/IP) level • Features: • Service verification: Broadcast and VOD services • GMP signaling emulation for Broadcast Video • RTSP signaling emulation for VOD • Video Transport Steam packet flow analysis • Video QoS, PID map, PSI analysis, • Packet Loss and Jitter and correlation with physical layer quality • Modes: • Terminate: Res Gateway or STB emulation • Monitor: Through or Ethernet Bridge • Integration into Process Improvement programs • Store and export results • Standard and custom scripts

  29. JDSU Application-Aware Solutions Equip work force for IP service testing as well as circuit testing Minimize customer site visits with centralized fault location Meet customer due dates – get to revenue quickly Ensure IP service QoS metrics are met producing good QoE – reduce churn Physical Layer Network Layer Data Link Layer Application Layer IP Signaling VoIP Voice Content Data IP ftp Video Physical Medium HTTP IP VOD Testing the Physical Medium is Not Enough . TM

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