1. Codec requirements update Michael Knappe Co-chair, codec WG 1Michael Knappe IETF 77

2. Codec requirements Current version draft-ietf-codec-requirements- 00, an informational docdraft-ietf-codec-requirements- 00 Jean-Marc Valin and Koen Vos are editors Action from March was to further explore and clarify a number of codec parameters and design choices Goal today: achieve consensus on a number of parameters / design choices, use as basis for update edits to the codec requirements Michael Knappe IETF 772

3. Discussion points Sample rates – 8, 16, 24, 32, 48 kHz – which, and how selected? – Will each sample rate be treated as a separate codec as far as SDP is concerned (IIAC8, IIAC16, IIAC48, etc) – What upper bound(s) for bit rates? – Sample rate layering? Operational modes / variants – Bit exact fixed point / lower complexity mode for constrained endpoints DESIRED – Joint stereo? Michael Knappe IETF 773

4. Discussion points Latency – Shall we Offer ‘low-delay’ mode (eg 5 ms) DESIRED Packet loss concealment – required as part of the codec package? YES – Performance goals for PLC? INFORMATIVE – ‘Upgradeable’ via bit-compatible modularity? YES – Integration with VAD/CNG? DESIRED Michael Knappe IETF 774

5. Backup / reference slides Michael Knappe IETF 775

6. VoIP transmission Encode Decode PLC / Comfort Noise VAD Jitter buffer EC TD EC Synchronous Asynchronous 6Michael Knappe IETF 77

7. Audio Transmission NomenclatureSampling rateUsable bandwidth Narrowband8 kHz200 to 3400 Hz Wideband16 kHz50 to 7000 Hz Super wideband32 kHz50 to 14,000 Hz Fullband44.1 kHz and up20 to 20,000 Hz Michael Knappe IETF 777 Useful comparisons: AM radio is limited to 5000 Hz audio FM radio is limited to 15,000 Hz audio CD is limited to 20,000 Hz audio Speed of sound in air: 343 m/s (approx 3 ms/m)

8. Audio frequencies Michael Knappe IETF 778 http://www.podcomplex.com/images/podco mplex-frequency-overview-chart.gif

9. Application Drivers ApplicationChannelsBandwidthEnd to end Latency Allowable complexity Allowable bit- rate Speech1 - 2NB - WB<150 msLow< 64 kbps Conference1 - 2NB - SWBActivity drivenMedium< 128 kbps Telepresence2+SWB - FBActivity drivenHigh< 512 kbps Gaming2+SWB - FB<150 msHigh< 320 kbps Interactive music 2SWB - FB< 25 msMedium< 256 kbps Content: even traditional phone calls handle signal types other than speech (e.g. music-on-hold), as a baseline we must assume non-specific audio content 9Michael Knappe IETF 77 Other useful features: packet loss concealment, quality and bandwidth layering, joint multi-channel encoding

10. Narrowband matrix (8 kHz fs) Codec Bit rate (kbps) Look ahead (ms) Frame size (ms) PSQM (zero impair) DTXPLC G.711 640Arbitr.4.45Appendix IIAppendix I G.723.1 5.3, 6.37.5303.6, 3.9 (MOS) Yes G.728 1600.5623.6 (MOS) G.729AB 85104.04Yes AMR 4.75 – 12.2 5204.14Yes GSM-EFR 12.2020 or 30Yes iLBC 13.33, 15.2 020 or 304.14 (15.2) Yes Michael Knappe IETF 7710 Sources: http://en.wikipedia.org/wiki/Comparison_of_audio_formats, Cable Labs PKT-SP-CODEC-MEDIA-I08-100120

11. Wideband + Michael Knappe IETF 7711 Codec Sample rate (kHz) Bit rate (kbps) Algorithm latency (ms) Comp Cmplx # ChanPLC G.711.1 8, 1664, 80 (8 kHz) 80, 96 (16 kHz) 11.8751 G.718 8, 16 (extens.) 8 - 3242.875 – 43.875 (20 ms frames) 1Yes G.719 4832 - 6440 (20 ms frames)18 FP- MIPS 1, MC (MP4) G.722 1664410 MIPSNo G.722.1(C) 16, 32 (c)24, 32, 48 (32)40 (20 ms frames)10 WMOPS Yes G.722.2 (AMR-WB) 166.6 – 23.852538 WMOPS 1, MC (MP4) Yes G.729.1 8, 168 - 3248.9375Yes Siren 16 - 4816 (m) – 128 (s)40 (20 ms frames)1 or 2 Speex 8 - 322 - 4430 NB, 34 WB1, 2 opt.Yes AAC-ELD ? - 48?24 - 6415 (64) – 32 ( 24)1+Yes