Iptv

IPTV Deployment: Performance Planning and Management Architecture Alan Clark CEO, Telchemy

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Internet Telephony - Fall 2005

Internet Telephony - Fall 2005

Outline • IPTV Delivery Architecture • Problems affecting performance • IPTV performance management architecture

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Internet Telephony - Fall 2005

IPTV System Overview Customer Premise

Video stream - H.264/MPEG 4 or VC1 At 500kbits/s - 6Mbits/s+

IPTV Set top

VOD Server

Residential Gateway

IP

Broadband

In-home wiring

Real Time Encoder

Service provider responsible for IP service quality

? UDP or TCP transport path

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Internet Telephony - Fall 2005

Potential problem areas Customer Premise

Home LAN speed/ link quality VOD Server

VoD Server Congestion

Access Link Congestion Congestion or shaping within IP network. Use of RED by routers.

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Internet Telephony - Fall 2005

Delivery Models

MPEG Transport over UDP

Packet loss leads to video quality degradation

TCP Streaming Packet loss leads to gaps in video playout. Set top box needs more buffer memory. Bulk download Delay in starting playback. Set top box needs mass storage.

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Internet Telephony - Fall 2005

Effects of packet loss on decoded video Anchor frames

Packet loss affects part of frame 6

Interpolated frames

Interpolated frames after damaged frame are impacted Internet Telephony - Fall 2005

Codec Performance vs Packet Loss 35 30

Better Codecs

PSNR (dB)

25 20

Problem area

15 10 5

Worse Codecs

0 0

5

10 Packet Loss (%)

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Internet Telephony - Fall 2005

15

20

Impact of loss/congestion on video stream

Video over UDP - impact of lost packets on video quality

Video over UDP - server congestion leads to gaps in playout

Video over TCP - impact of lost packets leads to gaps in playout

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Internet Telephony - Fall 2005

Example Packet Loss Distribution

los s

150

Co ns ec ut ive

Burst weight (packets)

200

100 50 0

0

100 One second

9

20

rst) u b e pars s ( y t i ens d t s r t bu n e c r pe

200

300

Burst length (packets)

Internet Telephony - Fall 2005

400

500

Leads to time varying quality (or gaps for TCP) 5 Mean Opinion Score

Base quality level depends on frame rate, codec type, bit rate

4 3 Average can be misleading

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Impact of Burst of Packet Loss

1 0

5

10 Time

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Internet Telephony - Fall 2005

15

20

Perceptual effects of changing quality

Good quality most of the time

5-8 seconds 15-30 seconds

Poor quality during burst of loss/discards 11

Internet Telephony - Fall 2005

Reported Call quality

IPTV Performance Management Customer Premise IPTV Set top VOD Server

Q

Q

Q

IP Q

Q

Broadband

In-home wiring

Real Time Encoder

Q

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Non-intrusive IPTV performance management function - IPTV video transmission quality - IPTV control function performance

Internet Telephony - Fall 2005

User “QoE”

Video transmission quality monitoring with VQmon/SA-VM Burst packet loss rate

Perceptual model

Calculate V factor

Ie mapping

Gap packet loss rate

V Factor - measures “Video Transmission Quality” & Degraded Quality Events

Video Codec Parameters

Frame Rate Bit Rate Video Content Factor

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Calculate Vo, Vs Calculate VQSsc

Internet Telephony - Fall 2005

VQS Score - reports “Video Objective Quality”

Calculate VQS score

Content dependency • Motion vs bandwidth or distortion – High motion = higher bandwidth or more blur

• Visibility of impairments – Small impairments less visible in certain types of video stream

• Emotional aspects – Final ball in final game in MLB playoffs

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Internet Telephony - Fall 2005

Summary • Successful IPTV deployment requires a focus on Quality of Experience (QoE) • Need to – Measure video transmission performance at key points along the transmission path – Measure IPTV control protocol performance

• One key group working in this field - ATIS IPTV Interoperability Forum (IIF) QoS task force

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Internet Telephony - Fall 2005