1. What’s new in Wideband Audio?

2. Wideband Audio
VoIP is indeed a disruptive technology, but has it changed the life of the average consumer?
Cost?
Quality?
Features?
Wideband Audio codecs and improved handling of music could soon change this dynamic
Let’s discuss
Technology behind the codecs
Real-world implementations

3. Telecom Audio Spectrum
Human voice: 80 Hz to 14,00Hz
Narrowband: 8 kHz sampling ( Hz bandwidth)
Used in PSTN, mostly intelligible
Wideband: 16 kHz sampling ( Hz bandwidth)
Used in VoIP

4. Wideband Audio? Captures significantly more speech information
Significant improvement in speech quality over traditional PSTN
Improved naturalness & presence below 200Hz
Increased intelligibility above 3,400Hz
Improves user experience and satisfaction
New applications – voice recognition
Customer retention
Fewer misunderstandings

5. Wideband Enablers Telecom was about minimizing transport cost
Now about differentiation and enhancing the user experience
Access bandwidth was limited
Broadband access now a reality: high bandwidth delivered at low cost
Mbits/s
Cost of WB is similar to 64kbps
Endpoints and Network were not wideband capable Now:
VoIP, Wideband DECT, Skype, Microsoft OCS
Wireless deployments: wideband, music codecs
Private / corporate networks, Tandem Free Operation (TFO), Wideband extension, Wideband SLICS

6. The Technology

7. Lossy Codec Classes Speech communication codecs (G.72X, AMR et.al)
Designed for “real-time” speech, music handled poorly
Low sampling rate (8-16KHz), low fidelity
Low-medium delay (10-30 ms)
Mostly time-domain (CELP is the most popular)
Music codecs (MP3, AAC, Vorbis)
Can encode any signal (not optimal for speech) – designed for entertainment
Up to 48 kHz sampling rate (full bandwidth), high fidelity (“CD-quality”
High delay (>100 ms)
Mostly frequency domain (MDCT-based)

8. Speech Codec Spectrum Applications Deployed Bandwidth Example Codec
More than 15Khz Full Band (20Khz)
AAC-LD
Presence (Video Conf)
14Khz Super Wideband
G.722.1C (Siren14), SILK
VoIP, Audio Conf
7Khz Wideband
G (AMR-WB), SVOPC
BB VoIP & Audio Chat
3.5Khz Narrowband
G.729, G G.711, iSAC
PSTN &VoIP

9. ITU and 3GPP codec roadmap
Super -wideband
EV-VBR
2008
G.722.2
AMR-WB
2002
G.729.1
2007
G.722
1988
G.722.1
1999
wideband
AMR-NB
1999
GSM-FR
1987
G.728
1992
GSM-HR
1994
GSM-EFR
1995
G.726
1984
narrowband
G.729
1995
Years
ITU
3GPP
3GPP
&
ITU
Legend:

10. Embedded Speech Codecs
ITU-Super WB
Provides extended bandwidth and stereo capabilities
16 KHz audible bandwidth
Stereo extension
Generic extension applicable to wideband codecs e.g.. ITU G & EV-VBR
3GPP-EPS (evolved packet system) (aka LTE)
ITU EV-VBR is well positioned to meet future EPS requirements
Interoperable with 3GPP AMR-WB.
Open Codecs
Speex (4 to 42Kbps)
Royalty free but limited to non patented techniques (ACELP for example)

11. Music Codecs MPEG-1 Layer III (aka MP3) AAC Vorbis
Built on top of Layers I and II
First-generation, very inefficient
AAC
Second generation, much better than MP3
Flexible, kitchen-sink type of approach
Tons of tools and partially incompatible profiles
Variants: AAC-LC, AAC-LD, AAC-HE, ...
Vorbis
Second-generation, similar quality to AAC
Open-source, royalty-free (Xiph.Org Foundation)

12. Future of codecs Improving quality Reducing delay
Super-wideband, coding of music
The gap between speech and music codecs is closing
AMR-WB+, G.722.1x moving to music, higher quality
AAC-LD moving to lower delay
Reducing delay
Increasing robustness
Shift from bit-error robustness to packet loss robustness

13. Improved Music Handling
Background music is poorly handled
Most speech codecs (AMR-NB, G.729, AMR-WB, Speex etc) are derivatives based on CELP
CELP makes assumptions that are only valid for speech (and single-note music)
CELP does not perform well on music – especially at low bit-rate
Music codecs are not suitable for speech

14. Improved Music Handling
How do you improve the handling of background music?
Three strategies:
Increase the bit-rate
Dual-mode codecs (e.g. AMR-WB+)
Use non-CELP codecs (AAC-LD, G.722.1x, G.711.1, CELT, …)

15. Wideband Extension (WEx) as an interim solution
How do you provide a wideband experience when linking a wideband-capable client to the PSTN?
Current solution: up-sample the narrowband speech to 16 kHz
Better solution: Create wideband “artificially” from the narrowband speech
Support becoming available
WEx capable handsets (Philips for example)
WEx enabled Media Gateway (Vocallo for example)

16. a.k.a The Role of the Media Gateway
The Implementations
a.k.a The Role of the Media Gateway

17. Wideband VoIP DECT - France Telecom
Mobile
Platform
IAD
Access
Platform IP
Network
TDM
Network
IMS GW
DLC
Access
Platform
IAD

18. Wide Band Extension (WBE)
Mobile
Platform
Wide Band Extension
Expand the signal to create impression of wideband.
AEC
ANR
NLE IP
Network
WBE
IMS GW
LEC
IP/DLC
TDM
Network
Access
Platform
DLC
IAD

19. Improving the User Experience
AEC
ANR
NLE
Wideband Lite Acoustic Echo Canceller acts as a complement to badly designed handset
Wideband Adaptive Noise Reduction reduces noise of mobile handset environment.
Wideband Natural Level Enhancement, uses info from intensity of the voice and SNR to compensate for loud environment of the talker
Mobile
Platform IP
Network
IMS GW
IP/DLC
TDM
Network
DLC
IAD
Access
Platform

20. The role of the MGW When selecting MGW solutions:
Don’t just look for checklist of codecs!
Look for solutions that provide wideband extension, wideband ECAN, ANR, etc.
Select solutions that incur low latency when transcoding IP-to-IP communications

21. Summary Clear benefit to the users
Skype changed expectation levels
Technology enablers already in place
VoIP deployment
CODECS
WB-enabled end-points and MGWs available