ip video quality testing
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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
ONT: Optical Network Terminal ONU: Optical Network Unit OLT: Optical Line TerminalRG: Residential Gateway VOD: Video On Demand IAD: Integrated Access Device
Service Delivery
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Splitter POTS
STB TV
PC
RG
DVB DEMUX
VoD
TV
QT-200
GbE
QT-1100
RF
GbE
xDSL
QT-1100
IP MPLS/ATM Core
LOCAL ADS& CONTENT
Eth AggrNetwork
QT-1100
D/AHub OfficeHead End
GbE
QT-600 QT-600
HST-3000
NetComplete
Triple Play Network/Service ChallengesComplex Network Environments require Service Assurance Systems to minimize expensive dispatches
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
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
Core Ntwk
Mistakes here catastrophic
Misprovisioned tributaries and routes
Routing/Link over utilization….poor traffic engineering.
Poor circuit routing…..creates excessive delays
Signaling and Media Gateways
Mis-provisioning creates incorrectly routed calls
Signaling translations and incompatibilities.
Echo Canceller configurations
IGMP and RTSP Latency
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 5-10% of Problems
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QoS and QoE mapping for Video Services
QoE Parameters
Continuity ErrorPCR Jitter
Error Indicator Count
Video QoS parts
IP Packet Loss
IP Packet Jitter
RTP Packet Loss
RTP Packet Jitter
TCP Re-transmissions
Service Provisioning
IGMP Latency
RTSP Latency
Content Quality
Transport Quality
Video Stream Quality
Transaction Quality
PSI Table Data (Error)
Picture: blocking, blurring, edge distortion, visual noise
Audio: Lip sync, drop outs
Pixelization, tiling frame freezes, Blue screen
Service accessibility, Channel Change latency Pause, Play Latency
Video QoS
V-MOS
Note 1: requires payload decode analysis
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IP Video Network Segment Test Focus-Broadcast
Content Quality
Transport Quality
Video Stream Quality
Transaction Quality
HE QoS Network QoS
Access QoS Total QoS @ STB
PCR Jitter Packet Loss Packet,
Jitter
Distance, Period
IGMP Latency, PCR Jitter, PSI data, Error
Ind, BW, MPEG-TS Pkt Loss, Jitter, Period,
Distance, MOS
Content Quality
Video Stream Quality
PCR Jitter, PSI Data, Error Ind, Compression – GOP, Type of
Coder, Bit Rate, Profile
Transport Quality
Transaction Quality
Video Stream Quality
Transport Quality
Transaction Quality
Video Stream Quality
Local Content Insertion
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IP Video Network Segment Test Focus-VOD
Hub Office QoS Network QoS
Access QoS
Total QoS @ STB
PCR Jitter Packet Loss Packet Jitter
Distance, Period
RTSP (Trick) Latency, PCR Jitter, PSI data,,
BW, MPEG-TS Pkt Loss, Jitter, Period,
Distance, MOS
PCR Jitter, PSI Data, Compression
(GOP, Type of Coder, Bit Rate,
Profiles), Trick Play Latency
Content Quality
Transport Quality
Video Stream Quality
Transaction Quality
Transport Quality
Video Stream Quality
Transport Quality
Video Stream Quality
Content Quality
Video Stream Quality
Transaction Quality
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CoreNetwork(ATM, IP)
GatheringNetwork
(IP)DSLAM
TV ProgramProviders
TV ProgramBroadcaster
MDF
VideoService
Platform
IP
STBATU-R
IP TV Installation
Local Content Added
Test Set STB/Modem emulation IP Video QoS check Broadcast & VOD
Network Specific Thresholds
IGMP signal
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ATM/IP
DSLAM
xTU-C Replacement
xTU-R Replacement RAS IP Routing
ISP
TE Replacement
Focus on showing end service functionality
• Connectivity to the DSLAM
• Connectivity to ATM network
• Connectivity to IP network and beyond
xDSL Verification
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Video QoS – Network Specific Thresholds
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%
Thresholds can be set in the HST for Pass, Fail, Marginal
If all items = Pass, no further analysis necessary by field tech.
If Error Indicator count = >0 then content problem
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Drop Packet
MPEG Decoder
1) Perfect Video StreamInter Frame delay OK
typically 2-4 ms
2) Stream with jitter or rate under run
Inter Frame delay to long
3) Stream with jitter and/or rate over run
Inter Frame delay to short
Video rate i.e 3 Mbps 3 Mbps
STB Buffer
Buffer overflows
Buffer underflows
Ethernet packet contains up to 7 MPEG packets
MPEG packet 188 Bytes
MPEG over Ethernet Transmission issues
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IP Video Testing
Video impairments– All channels?– One channel?
Time of day specific– A pattern?– Random throughout the
day? Temporal component
– Bursts?– Randomly spaced?
Critical Diagnostic Fault Conditions:
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IP Video Testing
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
IP Fault Resolution: Step #1
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IP Video Testing
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 issuesEvaluate copper loop for narrow band and wide band
issues. Use temporal input to pinpoint sources.
IP Fault Resolution: Step #2
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IP Video Testing
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 issuesEvaluate copper loop for narrow band and wide band
issues. Use temporal input to pinpoint sources.
IP Fault Resolution: Step #2
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IP Video Testing
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
IP Fault Resolution: Step #3
Yes
No
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IP Video Testing
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
IP Fault Resolution: Step #3
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”.
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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
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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
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Sources of Impulse Noise
Impulse count with 3dB below and above
threshold
Event capture
Impulse Noise Analysis
Proper Filter
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Up to 5 MHz
Up to 15 MHz
Up to 30 MHz
Spectral Noise Analysis
Spectral noise analysis down to -145 dBm/Hz
Wider VDSL spectrum opens loop to new noise sources
Max Hold shows transient peak values
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SAI
IP DSLAM
B-Box / SAI
VDSL
HST-3000STB
HPNA/VDSL in Home – VDSL2/Cu Noise/TDR
Splitter
CoaxAdapt
CPE
TWP
0-30MHzCopper Noise
VDSL2Sync
Analysis
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
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IP Video Testing
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
IP Fault Resolution: Step #4
CoreNetwork(ATM, IP)
GatheringNetwork
(IP)DSLAM
MDF
Multi-castPlatform
IP
STBATU-R
IGMP signal
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Video QoS – Packet Loss Correlation
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.
IP Fault Resolution: Step #5
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Video QoS Bandwidth & Pkt. Analysis
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.
IP Fault Resolution: Step #6
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MOS Score Evaluation
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.
IP Fault Resolution: Step #7
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PID Map & Combined Stream Data
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.
IP Fault Resolution: Step #8
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IPTV troubleshooting Putting Physical Analysis Together
DSLAMMDF
Street cabinet
Distributionbox
ADSL2+modem
Not twistedNot shielded pair
NID
ADSL tests PassedCopper tests Passed
Copper tests Failed (impulsive noise, spectral)
18 m280 m1330 m
ADSL tests Failed(ADSL errors within UP stream)Copper tests Failed (impulsive noise, spectral)
ADSL Example:
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IP Video Testing Focus Summary
– Video Services (Broadcast & VOD ) Verification and Quality analysis at the Video Packet 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
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Testing the Physical Medium is Not Enough
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 Medium
IPVOD
VoIP
Data
Video
Physical Layer
IPftp
HTTP
IPSignaling
Voice Content
Data Link Layer
Network Layer
Application Layer
TM
.