An Overlay Multicast Infrastructure for Live/Stored Video Streaming
270 likes | 802 Vues
An Overlay Multicast Infrastructure for Live/Stored Video Streaming Visual Communication Laboratory Department of Computer Science National Tsing Hua University Outline Live video broadcasting Typical service model Limitations Our goals Overlay multicast infrastructure Our previous works
An Overlay Multicast Infrastructure for Live/Stored Video Streaming
E N D
Presentation Transcript
An Overlay Multicast Infrastructure for Live/Stored Video Streaming Visual Communication Laboratory Department of Computer Science National Tsing Hua University
Outline • Live video broadcasting • Typical service model • Limitations • Our goals • Overlay multicast infrastructure • Our previous works • Multicast video streaming • Peer-to-peer search & delivery • Scalable video coding
Live Video Broadcasting • Techniques • Live video encoding • Multicast delivery • Commercial products • Windows Media Services (Microsoft) • Real System Server (Real) • QuickTime Streaming Server (Apple)
Service Architecture StreamServer (VOD) Stream Server (Live) Encoder Storage Internet (Live Broadcast) (VOD)
Multicast Routing Tree Client A (10:00) Client B (10:00) Client C (10:00) Client D (10:00)
5, 6, 7, … 1, 2, 3, 4 Common Solution: Prefix Caching • Permanently cache the front part of the video. • Clients request before (the start time + the length of the prefix) can see the entire video program. Prefix cache 1 2 3 4 C1
5 min store the first 5 min Client D (10:05) Multicast + Prefix Caching Client A (10:00) Client B (10:00) 5 min Client C (10:00) (10:05) queue the stream (10:10) read data from the buffer
Limitations • Must know the video source in advance. • Need router support. (IP multicast) • Cannot pass through firewall/NAT. • Users arrive after the system startup time cannot view the front part of the video. • Prefix caching is not perfect.
Scenario: Request & Playback • User input • Service mode (live/on-demand) • Video attributes • Peer-to-peer search • Streaming • Overlay multicast • Payment (?) • By service mode (VOD > live) (from server > from p2p) • By video (popular > unpopular) (bit rate) • By search method (advanced > basic)
Request flow distributed query input : service mode query rules init multicast video stream peer 0 EPG peer 1 Search Player peer 4 meta data P2P peer 3 peer 2
Topics in this project • Overlay multicast • Peer-to-peer infrastructure • Performance optimization • Two-mode multicasting • Live broadcasting (real-time) • On-demand streaming (see the entire video)
Advanced Topics (?) • Advanced electronic program guide • Intelligent search • Personal profile • Ambiguous keyword search • Melody / scene search • Distributed / continuous query • Matchmaker (?) • Meta datas • Creation/collection/distribution • Format (?) (object-based?)
Our Previous Works • On-Demand Multicast Streaming Delivery Platform • Technology and Systems • Peer-to-Peer Streaming Video (Directory Search) • Proxy-based Streaming Video • Multicast streaming platform for layered videos
10:02 10:01 10:02 10:04 10:03 On-Demand Multicast Communications 10:00 10:02 10:00 10:00 10:00 10:00 10:00 Source 10:00 10:04 10:00 10:03 10:00 Node with timing control
5 4 3 2 4 3 2 1 C1 C2 10:04 10:00 Interval Caching • Cache a sliding interval of the video. Caching buffer 2, 1 1 5, 4, 3, 2, 1 4, 3, 2, 1 1
Timing Control Mechanism 10:00 10:00 10:03 10:05 2, 1 7 6 5 4 3 To player D, 10:05 4, 3, 2, 1 To player C, 10:03 To player B, 10:00 7, 6, 5, 4, 3, 2, 1
10:08 10:06 On-Demand Multicast Routing source 10:06 10:03 10:02 10:00 Network • Constructing an on-demand multicast tree • find a routing path • allocate buffers to generate path delay
WWW Playback (with Directory Server) directory server Source 1 3 Proxy 4 7 IE 2 5 8 module.exe 6 module.exe Client
10:00 source client … … … Pi Pj Ps 10:02 Playback (Peer-to-Peer) • find a source • find a routing path • allocate buffers
P2P v.s. Proxy Platform Media Player • Mgmt. GUI • Network Mgmt. • QoS Reservation • Proxy • Protocol • Replacement • Chaining Media Player Video Streaming (HTTP) Video Streaming (HTTP) Virtual File System (Media Query) (Information Delivery) Proxy Selection & Chaining Cache Replacement Network Mgmt. IP Networks IP Networks QoS Proxy-Based Peer-to-Peer
11:32 11:33 11:34 11:35 Fault Handling Source One of the clients faults Auto reconfiguration 11:30 11:30 11:40 11:40 11:43 11:44
aggregated stream 1.5 Mbps Bottleneck = 0.7 Mbps 0.7 Mbps 1.5 Mbps High quality 0.8 Mbps 0.8 Mbps low quality 1.5 Mbps 0.8 Mbps Heterogeneous Network Bandwidth Server
Sender Layer L Lossy Channel … Scheduler Layer 2 Layer 1 Decoder with Error Concealment Receiver End-to-end Layer Subscription with Bandwidth Constraint
filename number of layers GUI (Media Player)