Presentation on theme: "N 2005-05-231 Team 15: Final Presentation Peter Nyberg Azadeh Bararsani Adie Tong N N multicodec minisip."— Presentation transcript:
N Team 15: Final Presentation Peter Nyberg Azadeh Bararsani Adie Tong N N multicodec minisip
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?
N About Minisip Minisip is software telephone –A SIP User Agent (UA)
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
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
N iLBC internet Low Bitrate Codec (iLBC) Free Robust voice communication over IP For narrow band speech
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
N iLBC Features Enables good speech quality degradation in the case of lost frame
N Speex Open-source Free from software patents Robust to packet lost
N Speex Design Goals Low bit-rate Good quality speech Unfortunately not at the same time!
N Speex Can Adapt to Bandwidth Speex uses: –Variable Bit-Rate (VBR) –Voice Activity Detection (VAD), integrated with VBR –Comfort noise generation
N Speex Features Narrowband (8 kHz) Wideband (16 kHz) Ultra-wideband (32 kHz) Stereo encoding
N Minisip Is Better Research project Excels in security; leading edge! No centralized control –Transparent calling –Greater choices for users Now even better!
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!
N Smarter More versatile More flexible Exciting future Standards compliant N N multicodec minisip