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

2. N 2005-05-232 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 2005-05-233 About Minisip  Minisip is software telephone –A SIP User Agent (UA)

4. N 2005-05-234 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 2005-05-235 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 2005-05-236 iLBC  internet Low Bitrate Codec (iLBC)  Free  Robust voice communication over IP  For narrow band speech

7. N 2005-05-237 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 13.33 kbit/s or 15.2 kbit/s

8. N 2005-05-238 iLBC Features  Enables good speech quality degradation in the case of lost frame  www.ilbcfreeware.org

9. N 2005-05-239 Speex  Open-source  Free from software patents  Robust to packet lost

10. N 2005-05-2310 Speex Design Goals  Low bit-rate  Good quality speech  Unfortunately not at the same time!

11. N 2005-05-2311 Speex Can Adapt to Bandwidth  Speex uses: –Variable Bit-Rate (VBR) –Voice Activity Detection (VAD), integrated with VBR –Comfort noise generation

12. N 2005-05-2312 Speex Features  Narrowband (8 kHz)  Wideband (16 kHz)  Ultra-wideband (32 kHz)  Stereo encoding

13. N 2005-05-2313 Minisip Is Better  Research project  Excels in security; leading edge!  No centralized control –Transparent calling –Greater choices for users  Now even better!

14. N 2005-05-2314 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 2005-05-2315  Smarter  More versatile  More flexible  Exciting future  Standards compliant N N multicodec minisip