For the Best Voice and Music, Will it be Opus or AAC?

By Doug Mohney September 25, 2012

Buried under the onslaught of iPhone 5 madness last week was finalization of the open-source Opus codec as an IETF codec. Audiophiles and open source gurus are enthusiastic and happy, but the Fraunhofer "Full HD" voice AAC family is already shipping on Apple iOS and Android devices. 

Will licensed beat open this time around?

Opus can trace its roots to not one, but two different wideband codecs. One part of the family tree traces back to the open-source Speex project and the other to Skype  and the SILK codec, with both sides lining up to propose a single standard to the IETF over three years ago.

The IETF RFC 6716 final specification became official on September 11, 2012, with reference code out the door the following day.  

Backers of the standard include Mozilla, Microsoft via its Skype subsidary, Xiph.Org, Octasic, Broadcom and (of course) Google. Opus is designed to be highly flexible, able to carry both voice and music over bit rates ranging from 6 kbps to 512 kbps in mono and stereo formats, with a sound range from 8 kHz narrowband to "Fullband" 48 kHz.

Royalty free and open source, Opus is capable of replacing at least six proprietary codecs covering from iLBC and G.711 codecs designed to carry narrowband voice all the way up through CD-and-better stereo music streaming using MP3 and AAC.

Opus is a mandatory-to-implement codec for WebRTC real time communications, so you'll see a lot of it in the programming community.

A single, open source, royalty-free codec (or at least fewer) would make life easy for programmers and device manufacturers, since they wouldn't have to support a lengthy-and-growing laundry list of code. Not to mention having to worry about license fees and having to keep track of per-device fees.

For the long term, Opus looks like a good bet. But it will have to wrestle with the likes of the Fraunhofer AAC codecs on mobile devices and smart TVs.

 Fraunhofer, the creator of the MP3 standard, have licensed what it has dubbed "Full HD voice" AAC codecs to Apple and Google for incorporation into iOS and Android devices. The technology company likes to boast AAC's use in Apple FaceTime with millions of users for video calling on iPads, iPhones and Macintosh clients. Numbers for Android apps using AAC aren't kicking around anywhere, but Fraunhofer has demonstrated the ability to make AAC phone calls between off-the-shelf Android smartphones over LTE  without breaking a sweat.

When the smoke clears, AAC is on a lot of end-point devices, but you have to pay for its use. The big cog that may prevent AAC from getting into the "mainstream" is transcoding between the format and lower quality formats. Companies involved with translating between narrowband and wideband codecs may not want to shell out the money to support AAC, preferring to support Opus because it's royalty free and open source. 

 Fraunhofer would likely argue that if you're in an all-SIP world, you don't have to transcode, but simply default to another codec if AAC isn't available between two clients. But if Opus is royalty free in the first place, maybe it becomes the default for voice, while AAC sticks around because of all the music content – such as iTunes songs – it can play back.




Edited by Jamie Epstein

Contributing Editor

SHARE THIS ARTICLE
Related Articles

500M Yahoo! Users Impacted by Hack; What It Says About Password Protection

By: Paula Bernier    9/23/2016

Yahoo! is facing a lot of challenges lately. Add to the heap the breach - which the company confirmed today - that has affected 500 million Yahoo! acc…

Read More

From Robotic Friends to Flying Cars: Looking Ahead to 2025

By: Rob Enderle    9/22/2016

I'm at the IBMEdge conference this week, and one of the topics that came up at lunch today was how robotics are going to dramatically change how and w…

Read More

Windows 10: Is it Worth the Update?

By: Alicia Young    9/22/2016

Last summer, Microsoft shook up their Windows design with the release of Windows 10. They offered the update to users for free for a year, giving ever…

Read More

Apple Making Serious Push Into Car Industry

By: Andrew Bindelglass    9/22/2016

Over the past two years, Apple has been seriously looking into entering the connected car industry, attempting to build its own electric vehicle that …

Read More

Will Legacy Paper Save Us From Electronic Fraud?

By: Doug Mohney    9/21/2016

Voting in the 2016 elections may be under threat from hacking, with the FBI worried about interference by a foreign power. Every day, I and tens of th…

Read More