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Enhancing MPEG Video Streaming Quality over Wireless Links

Learn about QoS in Digital In-home Networks - a project focusing on improving video streaming over wireless links. Explore the importance of frame types and the link layer approach for better transmission. Discover future plans and advancements since 2004.

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Enhancing MPEG Video Streaming Quality over Wireless Links

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  1. Streaming MPEG video over wireless link QoS in Digital In-home Networks PROGRESS project EES.5653 Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  2. Agenda • I-frame delay (summary on the approach) • Progress since May 2004 • Future plans • Demo Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  3. wireless Video over wireless link • Typical scenario: video transmission from a set-top box to the (mutiple) screens Between 5 and 13 seconds a microwave oven is on; Δt=50ms • Wireless link: • Low and highly variable throughput Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  4. Sender/receiver communication (RTP-based) video source video sink Packets get lost here sender buffer receiver buffer MAC retransmission mechanism wireless interface (sender) wireless inerface (receiver) Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  5. MPEG encoding • GOP (group-of-pictures): • Frame types: I, P, B • Typical GOP structure and dependences: I BBPBBPBB(I) Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  6. Importance of I and P frames • Missing of I/P frames causes video artefacts • A complete stream only missing B frames has • no artefacts In worst case you only get 8.3fps from originally 25fps Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  7. Cumulative weight of B-frames • An example of a 5Mbps stream (LOTR) • B-frames make up more than 50% of the whole bitrate Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  8. Link layer approach Sender MAC-retransmissions Application/ encoder Selectively drop frames here video stream IP packets OS network stack scheduler buffer Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  9. I-frame delay (IFD) Stream generated by application Transmitting under low and variable throughput: some frames take longer time Frames displayed at receiver – NN 1, 4, 5, 8 are skipped Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  10. Pros and cons of link layer approach • We only need to modify sending part • it will work with any terminals supporting RTP reception and equiped with a general MPEG decoder • due to RTP (UDP-based), it can be used for broadcasting • It is very reactive against fast network fluctuations • Requires access to wireless interface • should be implemented at every sending device Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  11. Deployment of IFD • ASL, SC (Ewout Brandsma, Eric Persoon) • CE: “Connected Planet” project (Tom Suters, Daniel Meirsman) • SLx00 products (“Streamium”) • CES at Las Vegas in June 2005 (with CE) • CRE in June 2005 (with ASL) Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  12. Progress since May 2004 • A publication submitted to WoWMoM 2005 • A demo set-up created • a number of successful demonstrations given • Deployment of IFD into real projects started (SC & CE) • Future work made concrete (coming slides) • Yesterday IFD proved to work with a Linksys AP • IFD and “wired + wireless” network • streaming to wireless CE devices (such as HotMan-2) new Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  13. Further work (I): Evaluation of IFD – models, simulations and optimizations Simulator (based on ns2) • variations of network topologies • variations of algorithms/buffer sizes for IFD • variations of video stream (GOP pattern variations, bit-rates, coding standards etc) Optimal settings are the simulation goal Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  14. Future work (II): IFD above transport layer • If... • we don’t have direct access to the wireless interface • we don’t want to modify it • we want to use it with both wired/wireless networks • we want it over a reliable transport protocol ... Then we would like to look at the tranport layer • implement the same idea in the application layer above TCP (master-student working on that) Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  15. Future work (III): IFD + SNR scalability (together with Dmitry) • The goal is to handle even higher variations in the link bandwidth • KISS project at NatLab is implementing it Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

  16. Welcome to the demo!(given after the meeting) • Questions? Sergei N. Kozlov, s.n.kozlov@tue.nl TU/e Informatica, System Architecture and Networking PROGRESS project EES.5653

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