OAC - Open Audio Codec - open publicly

[Kurt.noise]

After releasing AV1/AV2 video libraries, a new one related to audio has been released publicly by the Alliance for Open Media Group, a couple days ago. This is called OAC (https://github.com/AOMediaCodec/oac) (Open Audio Codec).

OAC intends to be the successor to Opus and liboac is based on libopus. Both are works in progress.

The Oac codec is designed for interactive speech and audio transmission over the Internet. It is designed by the IETF Codec Working Group and incorporates technology from Skype's SILK codec and Xiph.Org's CELT codec.

The Oac codec is designed to handle a wide range of interactive audio applications, including Voice over IP, videoconferencing, in-game chat, and even remote live music performances. It can scale from low bit-rate narrowband speech to very high quality stereo music.

Its main features are:


Sampling rates from 8 to 48 kHz
Bit-rates from 6 kb/s to 510 kb/s
Support for both constant bit-rate (CBR) and variable bit-rate (VBR)
Audio bandwidth from narrowband to full-band
Support for speech and music
Support for mono and stereo
Support for multichannel (up to 255 channels)
Frame sizes from 2.5 ms to 60 ms
Good loss robustness and packet loss concealment (PLC)
Floating point and fixed-point implementation

[hajj_3]

I can't find any announcements about this. Where did you get all those details from?

[Kurt.noise]

https://github.com/AOMediaCodec/oac/blob/bc9317c69dcc2e242068ea78799bcc67b8b1b77f/include/oac.h#L79

[VoodooFX]

Nice. Hopefully there will be more dev progress than in Opus.

[Z2697]

Hope there will be less sorcery in the CLI tool code structure design.

[hajj_3]

Its main features are:
Sampling rates from 8 to 48 kHz
Bit-rates from 6 kb/s to 510 kb/s
Support for both constant bit-rate (CBR) and variable bit-rate (VBR)
Audio bandwidth from narrowband to full-band
Support for speech and music
Support for mono and stereo
Support for multichannel (up to 255 channels)
Frame sizes from 2.5 ms to 60 ms
Good loss robustness and packet loss concealment (PLC)
Floating point and fixed-point implementation

this feature list is identical to opus except this is listed on opus but not for oac:

Dynamically adjustable bitrate, audio bandwidth, and frame size


i wonder whether they have just modified opus so that it doesn't violate patents from the opus patent pool (https://www.opuspool.com/patents).

[VoodooFX]

i wonder whether they have just modified opus so that it doesn't violate patents

Maybe they split it because they plan to brake Opus backwards compatibility.

[GeoffreyA]

It's a fork of libopus from February 17. Perhaps they wanted to take the encoder further but the Opus specification restricted them.

[Kurt.noise]

Here is a windows x64 binary (https://www.mediafire.com/file/7agbfqac7nt2lhi/oac-bc9317c_20260222.7z/file) in order to play with...

[hajj_3]

Dolby have now sued Acer and Beko over their use of Opus:

https://www.juve-patent.com/cases/dusseldorf-local-division-hears-dolby-vs-beko/
https://www.opuspool.com/media/vectis-opus-patent-pool-licensor-enforces-against-acer-before-the-upc

[Z2697]

The patents system is doing more harm than good at this point...

Oh by the way the largest entity that's using Opus is probably YouTube.
Dare not sue YouTube, LOL.

[john33]

The patents system is doing more harm than good at this point...

Nothing new there! The Patent system was supposed, originally, to encourage invention and innovation, but we all know that the opposite is actually what has really happened.

[Kurt.noise]

Dolby have now sued Acer and Beko over their use of Opus:

https://www.juve-patent.com/cases/dusseldorf-local-division-hears-dolby-vs-beko/
https://www.opuspool.com/media/vectis-opus-patent-pool-licensor-enforces-against-acer-before-the-upc
please, go away with your patent troll

[Z2697]

I "backported" some commits to Opus and they indeed break backward compability.

[hajj_3]

The developer of OAC has now said that OAC development is just starting and will use Opus as the starting point: https://hydrogenaudio.org/index.php/topic,129191.msg1078071.html#msg1078071

[kurkosdr]

Nothing new there! The Patent system was supposed, originally, to encourage invention and innovation, but we all know that the opposite is actually what has really happened.
That's highly opinionated, though. There is also the argument that patents encourage innovation, or in other words, that many coding tools wouldn't have been R&D'ed and invented if it weren't for the existence of patents and the royalties they bring. So, it quickly devolves into an argument where everyone can be "right" according to their opinion.

Something much simpler would be: if you claim one of your patents is essential to a standard, you must sue the top 3 implementers by volume.

This would allocate responsibility where it belongs: On the patent holders to add only essential patents in patent pools (or risk seeing them deemed non-essential or even invalid by some patent court) and on organizations like AOM to make sure they avoid the patents of third parties (or risk having to retroactively change the bitstream to avoid essential patents they don't own, which is the same status AOM is under now).

The current system, where any patent owner can add their patents into a pool and collect licensing fees from any implementer who bites (or go after small players whose litigation costs can be higher than settling and paying royalties), is ripe for abuse. The patent owners have all the rights but no responsibilities. And this legal harassment industry is quickly spilling into other areas such as copyright assertions against YouTuber channels.

[john33]

That's highly opinionated, though.Certainly is, but I stand by it. There is also the argument that patents encourage innovation, or in other words, that many coding tools wouldn't have been R&D'ed and invented if it weren't for the existence of patents and the royalties they bring.That was, indeed, the principle, but sadly the financial element rises above that. As I said in my comment, it was supposed to encourage invention and innovation, but it seems that the most trivial algorithms and expressions can be patented and I don't believe that was the original intent. Financial greed has taken over to the detriment of us all.

[modus-ms325c]

The developer of OAC has now said that OAC development is just starting and will use Opus as the starting point: https://hydrogenaudio.org/index.php/topic,129191.msg1078071.html#msg1078071
hey bois, here's what i'm working on: how to make ass more listenable. it's not ready tho!
xxxxxxxxxxxxxxxxxxxxxxxxx sick of this crap song-and-dance, so much so i've left out an short but irate tl;dr about it there (https://hydrogenaudio.org/index.php/topic,129191.msg1078184.html#msg1078184).

[Z2697]

?????