Microsoft PowerPoint workshop.ppt

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1 IPTV 서비스품질기술 이철희연세대학교

2 네트워크를이용한멀티미디어서비스 채널용량이증대함에따라네트워크를이용하여새 로운서비스가능 멀티미디어서비스 (VOD, MOD, 화상전화등 ) IPTV 인터넷, 무선통신등이주요역할기대. HDSP lab. 2

3 네트워크를이용한멀티미디어 vs 기존방송비교 기존방송 대역폭보장됨 적절히설치되면일반적으로품질보장 전송에러거의없음 실시간전송이아무문제없음 네트워크를이용한멀티미디어서비스 (IPTV 등 ) 대역폭보장어려움 데이터폭주시품질저하 실시간전송을보장하기어려움 HDSP lab. 3

4 수익구조 기존방송 시청료 광고수입 네트워크를이용한멀티미디어서비스 (IPTV 등 ) 시청료 광고수입 PPV (VOD, contents-based billing) 품질보장필요. HDSP lab. 4

5 네트워크를이용한멀티미디어서비스장점 통신망을이용함으로기존에불가능했던새로운서 비스가능. 개인수요맞춤형서비스 무제한프로그램제공가능 국경에영향받지않음 이동중에도이용가능 HDSP lab. 5

6 Challenges of Multimedia Services over Networks 100% 품질보장불가능. PPV 에서는품질보장필요. 열화발생시, 쌍방이동의할수있는방법으로요금 정산필요 품질모니터링은중요한문제로부각. 품질측정에관한국제표준필요. HDSP lab. 6

7 QoE Requirements for IPTV

8 Video Requirements for IPTV: video QoE for video Resolution, bit rate, application layer video encoding, encoder setting (GOP) Codec: MPEG-2, MPEG-4 AVC (MPEG-4 Part 10 or H.264), SMPTE VC-1 Video Codec MPEG-2 - Main profile at Main level (MP@ML) MPEG-4 AVC (Main profile at Level 3) SMPTE VC-1 Minimum Bit Rate (SD / HD) 3.18 Mbps CBR / 15 Mbps 2.1 Mbps CBR / 10 Mbps 2.1 Mbps CBR / 10 Mbps HDSP lab. 8

9 Audio Requirements for IPTV QoE for audio channels: mono, stereo, 5.1 channels sampling rates: 16-48kHz 오디오코덱 채널수 Minimum Bit Rate (kbps) MPEG Layer II Dolby Digital (AC-3) AAC MP3 (MPEG-1, Layer 3) Mono or stereo 5.1 if available, else left/right stereo pair Stereo Stereo 128 for stereo 384 for 5.1 / 128 for stereo 96 for stereo 128 Audio Video Synchronization Audio Lead Video 15 ms maximum Audio Lag Video 45 ms maximum HDSP lab. 9

10 QoE Requirements for IPTV QoE for control functions 채널변경시간 VOD trick mode QoE for EPG 사용자편의성 응답시간 QoE for Metadata: Availability, Data size, Correctness QoE for Browser: Characteristics of a television set, TV-like display, 글자크기, Navigation, Cookie HDSP lab. 10

11 품질보증을위해취할수있는방법 Traffic management Application layer reliability solutions HDSP lab. 11

12 Traffic Management for IPTV Control plane Data plane Multicasting HDSP lab. 12

13 Traffic Management for IPTV Control Plane admission control (IETF RFC 2753) Admission control meets requirements for IPTV multicast/unicast services as negotiated in the SLA. The network needs to properly engineered to accommodate the number of subscribers. QoS routing (ITU-T Rec Y.129) This method is used to control network congestion and improve network utilization by selecting an appropriate path Resource management network traffic management according to the network information by means of data transmission between the network resource manager and the network nodes HDSP lab. 13

14 Traffic Management for IPTV Data Plane Traffic conditioning (required in access network) QoS provisioning per subscriber and per service Traffic classification based on multiple header fields (5-tuple, 6-tuple, and etc.) Minimum bandwidth guarantee Traffic shaping/policing Advanced packet queuing and scheduling Traffic marking (DSCP, 802.1p, and etc.) HDSP lab. 14

15 Traffic Management for IPTV Data Plane Transmission schedulers First-in, first-out scheduler Round-Robin Scheduler Priority scheduler Weighted Round-Robin scheduler Class-based schedule Buffer management HDSP lab. 15

16 Traffic Management for IPTV Multicasting Multicast replication point HDSP lab. 16

17 Traffic Management for IPTV: Y.1541 IP network QoS class definitions and network performance objectives/applications HDSP lab. 17

18 Traffic Management for IPTV Network QoS Classes ITU-T Recommendation Y.1541 (8 QoS classes) 등을참고하여 IPTV 규격논의중 IPTV 서비스를 5 가지경우로분류 1 Best Effort 서비스 (QoS class 5): content download 서비스, 정기적인정보 제공, T-information, 이메일 2 Low Loss 서비스 (QoS class 4): VOD, MOD, T-commerce, VOD 기반 T- learning Interactive 서비스 (QoS class 2/3): 메신저, T-learning based on interactive Real-Time Interactive 서비스 (QoS class 0/1): VOIP, 화상전화, 다자간게임 Real-Time Multicase & Unicast 서비스 (QoS class 6/7): linear/broadcasting, multi angle, PPV, PVR HDSP lab. 18

19 Traffic Management for IPTV Cross-layer interaction for IPTV services Traffic management capabilities: core networks Traffic management capabilities: acces networks Traffic management capabilities: home networks HDSP lab. 19

20 Application Layer Reliability Solution for IPTV

21 Application Layer Reliability Solution for IPTV 전송오류복구방법 Retransmission FEC (Forward Error Correction) hybrid combinations of both HDSP lab. 21

22 Retransmission Reference [IETF RFC3550] [IETF RFC3556] [IETF RFC3605] [IETF RFC3611] [IETF RFC4585] Title Real Time Protocol: A Transport Protocol for Real-Time Applications Session Description Protocol (SDP) Bandwidth Modifiers for RTP Control Protocol Real Time Control Protocol (RTCP) Attribute in Session Description Protocol (SDP) Real Time Protocol Control Protocol Extended Reports (RTCP XR) Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF) [IETF AVT- RTCPSSM] draft-ietf-avt-rtcpssm-13.txt HDSP lab. 22

23 FEC (Forward Error Correction) Forward Error Correction (FEC) at the Application/Transport layers Packet erasure correction techniques FEC for Streaming Applications IETF RFC2733 [IETF RFC2733] 3GPP TS Multimedia Broadcast/Multicast: Protocols and Codecs [3GPP TS26.346] ETSI EN Digital Video Broadcasting: DVB Specification for Data Broadcasting [ETSI EN ] ETSI TS Transport of MPEG 2 Transport Stream (TS) Based DVB Services over IP Based Networks [ETSI TS ] HDSP lab. 23

24 FEC for Download Services IETF RMT working group standardizes protocols for reliable file delivery over IP multicast. Reference [IETF RFC2887] [IETF RFC3048] [IETF RFC3269] [IETF RFC3450] [IETF RFC3451] [IETF RFC3452] [IETF RFC3453] [IETF RFC3695] [IETF RFC3926] Title The Reliable Multicast Design Space for Bulk Data Transfer Reliable Multicast Transport Building Blocks for One-to-Many Bulk-Data Transfer Author Guidelines for RMT Building Blocks and Protocol Instantiation Documents Asynchronous Layered Coding Protocol Instantiation Layered Coding Transport (LCT) Building Block Forward Error Correction Building Block The Use of Forward Error Correction in Reliable Multicast Compact Forward Error Correction (FEC) Schemes FLUTE - File Delivery over Unidirectional Transport HDSP lab. 24

25 Performance Monitoring for IPTV

26 Performance Monitoring for IPTV 현재인터넷은특성상 bandwidth 보장어려움품질은전송상태에따라가변적임필연적으로발생하는품질저하문제를서비스제공업자및사용자가동의할수있는방법으로해결필요. 특히화상전화, pay-per-view에서는품질에근거한과금필요이를위하여체감품질모니터링기술필요 HDSP lab. 26

27 Performance Monitoring for IPTV 모니터링파라미터 Physical Layer Parameters IP Layer/Network Parameters Transport Stream parameters Service Line-Up parameters Channel Attribute parameters VOD Parameters Other Parameters HDSP lab. 27

28 Performance Monitoring for IPTV Physical Layer Parameters 1 RF intergrity 2 Available bandwidth HDSP lab. 28

29 Performance Monitoring for IPTV IP Layer/ 네트워크파라미터 Link IP layer used/available bandwidth End-to-end IP layer bandwidth End-to-end IP layer available bandwidth Loss run length distribution Error-free interval distribution Packet loss metrics and models Streaming jitter HDSP lab. 29

30 Performance Monitoring for IPTV Service Line-Up parameters Video Audio Meta data Subtitles EPG Parental control HDSP lab. 30

31 Performance Monitoring for IPTV Service Line-Up parameters Channel line up Service meta-data (eg. EPG, subtitles, parental control, etc.) Channel zap time Correctness Rate Channel Attribute parameters Channel attributes Video quality Audio quality Ancillary channel associated attributes (subtitles, closed captions, descriptive audio) VOD Parameters HDSP lab. 31

32 Performance Monitoring for IPTV Monitoring Methods Generalized monitoring method for multi-media data based on transmission packet loss Bearer network monitoring Network performance monitoring IPTV service attribute monitoring Video quality monitoring Audio quality monitoring HDSP lab. 32

33 객관적화질평가방법분류 Full Reference ( 전기준법 ) 기준영상제공 응용분야 : Codec 성능평가, 디지털방송, 멀티미디어장비성능평가 Reduced Reference ( 감소기준법 ) 압축영상과 reference bit-stream 함께전송 허용 reference bit-stream: 10Kb, 56Kb, 256Kb 응용분야 : 무선통신멀티미디어전송, 채널상태에대응하여 parameter 최적화 No Reference ( 무기준법 ) 수신동영상만으로화질평가 상대적으로신뢰도저하 응용분야 : 무선통신멀티미디어전송, 채널상태에대응하여 parameter 최적화 HDSP lab. 33

34 객관적화질평가시스템구성도 Video Source Digital Channel Multimedia terminal Encoder Decoder FR RR Extracted Feature RR NR Performance Measurement system HDSP lab. 34

35 전송에러를이용한화질평가방법 (J.242) 패킷을사용한비디오전송에서는전송에러정보를이용하여수신동영상추정가능 대역폭사용을최소화하면서수신측의화질모니터링가능 IPTV, 화상전화, VOD 등에적용가능 Head-end (service provider) Receiver source video encoder transmitter decoder received video packetized video data received video estimation unit transmission error detection unit estimated received video video quality evaluation unit

36 Hybrid Perceptual/Bit-stream Models bit-steam analyzer - codec parameters -bitrate -FPS - packet information if available - IP information - transmission error information (lost or delay packets, impaired block lost or delayed frames) channel decoder PVS Hybrid perceptual bit-stream NR model

37 Hybrid Perceptual/Bit-stream Models SRC encoder objective model compression error MUX bit-steam analyzer - codec parameters -bitrate -FPS - packet information if available - IP information - transmission error information (lost or delay packets, impaired block lost or delayed frames) channel decoder PVS Hybrid perceptual bit-stream NR model video quality scores

38 Streaming Server with Quality Monitoring and Optimization Development of streaming server with quality monitoring capability and optimization. Optimization of streaming technologies based on quality monitoring results (e.g., codec parameter, application layer reliability solutions). SRC encoder streaming server channel receiver quality monitoring

歯이시홍).PDF

歯이시홍).PDF cwseo@netsgo.com Si-Hong Lee duckling@sktelecom.com SK Telecom Platform - 1 - 1. Digital AMPS CDMA (IS-95 A/B) CDMA (cdma2000-1x) IMT-2000 (IS-95 C) ( ) ( ) ( ) ( ) - 2 - 2. QoS Market QoS Coverage C/D