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N 2005-05-231 Team 15: Final Presentation Peter Nyberg Azadeh Bararsani Adie Tong N N multicodec minisip.

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Presentation on theme: "N 2005-05-231 Team 15: Final Presentation Peter Nyberg Azadeh Bararsani Adie Tong N N multicodec minisip."— Presentation transcript:

1 N Team 15: Final Presentation Peter Nyberg Azadeh Bararsani Adie Tong N N multicodec minisip

2 N Have You Ever?  Been shocked by outrageous phone long-distance rates?  Voice-over-IP telephony is free!  Smarter and adaptive use of speech codecs!  Tried to talk using a phone but only gotten static?

3 N About Minisip  Minisip is software telephone –A SIP User Agent (UA)

4 N VoIP Telephony with SIP MiniSIP or other User Agent Internet I want to call you! Yeah! Me too! MiniSIP or other User Agent Speech audio data SIP Server

5 N VoIP Telephony with SIP MiniSIP or other User Agent Internet I want to call you! G.711 Speex Yeah! Me too! Speex iLBC MiniSIP or other User Agent Speech audio data … using Speex

6 N iLBC  internet Low Bitrate Codec (iLBC)  Free  Robust voice communication over IP  For narrow band speech

7 N iLBC Options  2 encoding frame length: 30 ms and 20 ms  400 bits per block, packetized in 50 bytes 304 bits per block, packetized in 38 bytes  Bit rate of kbit/s or 15.2 kbit/s

8 N iLBC Features  Enables good speech quality degradation in the case of lost frame 

9 N Speex  Open-source  Free from software patents  Robust to packet lost

10 N Speex Design Goals  Low bit-rate  Good quality speech  Unfortunately not at the same time!

11 N Speex Can Adapt to Bandwidth  Speex uses: –Variable Bit-Rate (VBR) –Voice Activity Detection (VAD), integrated with VBR –Comfort noise generation

12 N Speex Features  Narrowband (8 kHz)  Wideband (16 kHz)  Ultra-wideband (32 kHz)  Stereo encoding

13 N Minisip Is Better  Research project  Excels in security; leading edge!  No centralized control –Transparent calling –Greater choices for users  Now even better!

14 N Further Exciting Research  Forward-Error-Correction techniques –can increase quality over lossy connections  Starting point for dynamic codec switching –Measuring the available bandwidth and change codecs and parameters automatically –Adopt to the conditions at hand –Radical improvement in quality possible!

15 N  Smarter  More versatile  More flexible  Exciting future  Standards compliant N N multicodec minisip


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