New Standard: USAC, sussesor of (HE)-AAC Options

[IgorC]

It's a new standard (Unified Speech and Audio Coding – USAC, aka MPEG-D part 3).
It has reached a status of Final Draft International Standard.

Basic information http://en.wikipedia.org/wiki/Unified_Speech_and_Audio_Coding
There are some papers about new compression schemes in internet.

There was a verification test where USAC was compared to HE-AAC v1/v2 on range of bitrates 8-96 kbps. http://mpeg.chiariglione.org/meetings/tori...orino_press.htm
The report should be available in September – October.

Some anonymous source has indicated that USAC was clearly superior to HE-AAC and it did very good on speech though something like "USAC at 48 kpbs = HE-AAC at 64 kbps" shouldn't be expected. It's more like 20-25% of bitrate gain at 20-32 kbps and 10-12% at 64 kbps. That's still pretty good.

There is no information if USAC will be used at higher bitrates as ( LC-AAC's area). The core coder of USAC includes a new enhanced SBR (eSBR).
Both SBR and new eSBR have no advantage over LC-AAC at bitrates higher than 80 kbps. It’s unclear if eSBR can be disabled at higher bitrates.


It will be interesting to hear opinions and if somebody knows something more about it.

[polemon]

For me, as a Linux user, developer of embedded systems and free software advocate, I look at it with a certain skepticism.

While the technology is exciting and interesting, it will leave out the users from becoming developers and/or contributors. USAC might very well linger around like AAC does for the most part. It is out of question, that USAC will be heavily patented. There are some encoders out there, that produce great results when encoding AAC, but most of them aren't free. As I understand it, due to patents, it is quite dificult to use AAC in embedded devices. That's one of the reasons, why most car navigation systems use Ogg/Speex for speech, etc.
I recon, apart from some niche applications, USAC will remain obscured, just like AAC for the average user. As for developers, they will turn to whatever is best, free and available. Once reason more to use Xiph things, as many game developers do as well.

[C.R.Helmrich]

I recon, apart from some niche applications, USAC will remain obscured, just like AAC for the average user.

Well, (HE-)AAC is used in DAB+, DRM, DMB, Youtube, iTunes Store, H.264 video from mobile devices, and some more. Whether these are niche applications is debatable, I'd say.

Think of it this way: years or R&D and over a million Euros/Dollars went into the standardization of AAC and now USAC. I wouldn't understand why one should give away the use of such highly specialized, sophisticated technology for free.

sooner or later all kinds of multimedia material will be detached from the physical media. Once that is the case, it only makes sense to use the best encoders available.

Both absolutely true. But the media creators (music distributors, digital camera manufacturers, etc.) already nowadays license the AAC encoders, so it seems they are willing to pay for the technology. Of course it's a different thing if you create your own media content, e.g. edit home videos or your band's music. Isn't there any commercial software like Adobe Premiere for Linux with in-the-box state-of-the art encoders?

Chris

This post has been edited by C.R.Helmrich: Oct 13 2011, 20:42