Seems to cover a wide range of range applications. I wonder why they left out loseless encoding. That would have made it the one true codec for everything.

Yup, that was my thought the moment I read this - and I bet it was the case for a large number of other Slashdotters as well.

As far as being "good or better than existing proprietary codecs" go... I'll wait and see what people less invested in Opus say. We heard the exact same things about WebM, and the various Oggs before that - and it turned out not to be the case, unless the "Free" status of a codec was given significant weight in the quality space.

Opus has support for up to 255 channels [wikipedia.org]. Indeed, lossless was the most glaring omission, but considering the obsolescence of MP3HD [wikipedia.org], I think they must had good reasons to leave it out.

Umm, no. The more subtle the difference, the better hearing you need to be able to resolve an AXB comparison. (Is sample X equivalent to A, or equivalent to B).

If you can hear a difference with poor hearing, then it must be substantial.

"What would make an audio codec something worth using that would make you switch?"

A car stereo that supports it, phones that support it, etc... There is a reason that mp3 is still the king, it can be played on 98,543,221.5 different brand sof devices and another 800 are created that support mp3 every 6 seconds.

Ogg? 5 devices.
Apple's codec? 5 devices.

mp3 will be around for another 10 years simply because I can buy a $0.25 chip and make the toaster my company is making play mp3's.

Using Vorbis as an example, it's actually commonly used in a number of applications (like video games) where they don't want to pay licensing fees for every copy sold. Unfortunately, this doesn't translate very well to consumer usage. People paying for music are getting it in AAC, and people downloading it are getting it in MP3. Transcoding the audio is essentially a loss no matter what.

If Windows, Mac, and Android all began including the codec automatically then you could potentially see quick uptake. That's unlikely to happen though, so it's going to be a long uphill battle. Of course, we're likely reaching the point of diminishing returns, so battle could go one for a decade or possibly even multiple decades gaining traction and eventually becoming the market leader. At the very least it will be used in the backend of applications.

If it fully succeeds, then we all benefit from better audio reproduction and no licensing costs. If it's success is limited, then we still benefit from better audio reproduction within application and lower licensing costs. Either way it's a win.

Did you forget that a "music player" these days is actually a phone with four processors running at 1Ghz+ ?

The reason Opus is already a failure is twofold.

1) Nobody but the most prudish music snob with lots of time to waste and $1000 Sennheiser headphones is ever going to be able to tell a sound quality difference between Opus and MP3, Ogg Vorbis, AAC or whatever else.

2) Opus is not supported by most music player software or hardware and probably never will be.

AAC & MP3
-already have widespread use
-multiple implementations in hardware producing acceptable quality output using minimal power [for example, there are no widespread complains about audio qualify from iPods by consumers]
-fixed, known licensing fee's [in the pennies per unit range]

Opus
-nobody uses it for anything
-must use a software decoder, much more expensive power-wise
-offered for free, but of course, it's unknown if it infringes on any patents

So, if you are a device manufacturer, why would you spend any effort on this, when the existing solution you have already works acceptably for 99% of your customers, you won't save any money anytime soon [as you can't drop MP3/AAC support, because everybody's music is in that format], you open yourself up to patent trolls?

The point is to be able to use lower bitrates and get the same quality. This is especially useful for things like audio streaming over the internet, where less bandwidth used equals more space for listeners.

Even then, I suspect a heavily power-optimized ARM core might be better than some custom hardware that's designed just for Opus. Keep in mind that any hardware you design will still have a fully programmable core in it, so in the end what you gain by doing more stuff in hardware you lose by not having your chip nearly as optimized as a more general-purpose CPU.

Short version for you: Microsoft - Skype. Can you figure it out now?