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Robust Audio Tool (RAT)

Robust Audio Tool (RAT). Speaker : Wei-Shin Pan DATE : 09/07/02. OutLine. Introduction. RAT . Keep going. DEMO. Introduction. An open-source audio conferencing and streaming application RAT transmission Unicast (Point-to-point streaming) Multicast (conference)

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Robust Audio Tool (RAT)

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  1. Robust Audio Tool (RAT) Speaker : Wei-Shin Pan DATE : 09/07/02

  2. OutLine Introduction RAT Keep going DEMO 2009 Graduate Institute of Communication Engineering

  3. Introduction • An open-source audio conferencing and streaming application • RAT transmission • Unicast (Point-to-point streaming) • Multicast (conference) • 224.2.0.0 – 224.2.255.255 2009 Graduate Institute of Communication Engineering

  4. Architecture(1) • Three components Ratmedia RAT Ratui 2009 Graduate Institute of Communication Engineering

  5. Architecture(2) • RAT • arguments analyzing and controls the other components. • RATmedia • voice processing and transmisstion • RATui • Graphical user Interface 2009 Graduate Institute of Communication Engineering

  6. RAT • How to start • RAT Get ! • https://frostie.cs.ucl.ac.uk/mbone/mmedia/wiki/RatDownload • Choose the build platform • The stable version : RAT4 (4.4.01) • Installation • Start it ! • RAT launched from the command line • Syntax : • > rat address/port 2009 Graduate Institute of Communication Engineering

  7. User interface 2009 Graduate Institute of Communication Engineering

  8. Configuration • Options • Personal • Transmission • Reception • Audio • Codecs • Security • Interface 2009 Graduate Institute of Communication Engineering

  9. Personal 2009 Graduate Institute of Communication Engineering

  10. Transmission 2009 Graduate Institute of Communication Engineering

  11. Codecs • G.711 u-law & a-law 64kbit/s , MOS 4.3 • Linear-16 128kbit/s (RAW) • GSM 13.2kbit/s , MOS 3.5 2009 Graduate Institute of Communication Engineering

  12. Loss protection(1) • Loss protection 2009 Graduate Institute of Communication Engineering

  13. Loss protection(2) • Redundancy 2009 Graduate Institute of Communication Engineering

  14. Loss protection(3) • Layering 2009 Graduate Institute of Communication Engineering

  15. 2009 Graduate Institute of Communication Engineering

  16. Repair scheme • Pattern-Match • 將遺失的部份聲音,以它前後的聲音透過interpolate來回復,需較大的計算量 • Repeat • 基於人聲沒有快速變化的特性,將遺失掉的封包用前一個封包來代替,但當封包長度和封包遺失率太大時,就沒辦法利用人聲的特性了 • Noise • 透過隨機分佈雜訊聲音來取代遺失的聲音區塊,會被封包長度跟封包遺失率大小所影響 2009 Graduate Institute of Communication Engineering

  17. Sample rate conversion • If local’s soundcard can’t support sample rate of received packets , and converting the sample rate by this option. 2009 Graduate Institute of Communication Engineering

  18. Limit Playout delay • Jitter • jitter buffer • Adjustable range : 0-2000ms • IF value is high, the voice packets will play smoothly and poor quality (high delay) • IF value is low, some voice packets can’t play because the delay too short. 2009 Graduate Institute of Communication Engineering

  19. Jitter Buffer (With Playoutbuffer)is designed to remove the effects of jitter from a decoded voice stream and buffer each arriving packet for a short interval before playing out. This compensates an additional delay and packet loss for jitter. Jitter buffer 2009 Graduate Institute of Communication Engineering

  20. 2009 Graduate Institute of Communication Engineering

  21. Silence suppression • Much silence gaps (No talking) in a conversation • Background Noise • No packet sending will reduce 50% bandwidth 2009 Graduate Institute of Communication Engineering

  22. 2009 Graduate Institute of Communication Engineering

  23. DES (data encryption standard) 2009 Graduate Institute of Communication Engineering

  24. 2009 Graduate Institute of Communication Engineering

  25. 2009 Graduate Institute of Communication Engineering

  26. DEMO 2009 Graduate Institute of Communication Engineering

  27. Reference [1] The Study and Analysis of the Robust-Audio Tool for Real-Time Audio Conference, Ting-Yu Chiu [2] Robust Audio Tool official website 2009 Graduate Institute of Communication Engineering

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