Protocols and Algorithms for Adaptive Multimedia Systems

Lectio Praecursoria
Varun Singh, Espoo

Ph.D. Defense opening lecture

Transcript

1. Protocols and Algorithms for Adaptive Multimedia Systems Lectio Praecursoria Varun Singh 02.06.2015 Espoo 1
2. Video is Everywhere! 2
3. Dominance of Video • ~ 60% of the broadband Internet is Video Content • ~ 70% of the mobile Internet is Video Content • ~ 10% of the mobile Internet is Video Calls 3
4. Internetworking • Available capacity varies over time mainly due to sharing with 1. various types of cross traffic 2. wireless networks 4
5. Emergence of low-delay Video • Live video • delivered within seconds • Interactive video • at most hundreds of milliseconds 5
6. Multimedia Systems • connected to a network • capture and transmit media • receive and render media • video codecs: e.g., H.264, VP8, … • audio codecs: e.g., G.711, Opus, … 6
7. Protocols (RTP) Internet Protocol (IP) User Datagram Protocol (UDP) Session Traversal Utilities for NAT (STUN) RTP SSRC #2 SSRC #1 TURN SSRC #3 SSRC #4 Transmission Control Protocol (TCP) Signalling Protocol (e.g., SIP, Jingle, …) DTLS Note: *RTP can be sent over UDP or TCP. Similarly, signalling protocols can be designed to transmit over UDP or TCP. Secure RTP (SRTP) Keying 7
8. Sender Receiver RTP media packets Sender and Receiver Reports Adaptation 1. Short-term 2. Long-term 8
9. Congestion Control *Rate Control ! Time Instant per packet delay Threshold 2 Threshold 1 (2) Short-term delay peak (1) Time period of excessive delay (5) Integral under the delay curve 9
10. End-to-end Congestion Control Network Ethernet Wireless Cable/xDSL 10
11. Network Assistance notifications notifications 11
12. Multiple paths Wifi and 3G/LTE … 12
13. Conclusion • Classification of congestion control cues. • Adaptive error-resilience • Congestion control for real-time media • Multipath RTP 13