[cogman10]

Man what a showcase for Opus this is.

Don't get me wrong, this sort of thing is a valuable exercise and we are better off with better encoders for these older codecs. But look at the numbers for Opus on this benchmark. It simply blows all the AAC encoders out of the water even at 64 kbps.

[ndiddy]

The biggest advantage for having a good AAC encoder isn't efficiency, it's that for nearly the past 2 decades the de facto standard for live streamed video has been RTMP with H.264 video and AAC audio. There is basically no support for any other codecs. If you want to send a video stream to Youtube or Twitch, you will be sending H.264 and AAC. If you want an idea of how ubiquitous this is, I just checked in OBS and it will not even let you select different video and audio codecs in streaming mode, it just (correctly) assumes that anybody who's streaming will be streaming H.264 and AAC.

[jshier]

YouTube actually supports H.265 and VP9 ingest, depending on the streaming protocol. I can actually stream 4K@60 H.265 from my Mac Studio with < 5% CPU usage due to the hardware encoder support in OBS.

https://developers.google.com/youtube/v3/live/guides/ingesti...

[ndiddy]

Nice, glad some sites are finally trying to move forward. It looks like they only support H.265 video with AAC audio, so this should still be helpful for people who are streaming H.265. https://developers.google.com/youtube/v3/live/guides/hls-ing...

[davidgerard]

yeah I use vp9 with opus for uploads by choice, it's great!

YouTube serves vp9 but it always re-encodes my videos as AV1. Annoying.

(I would upload as AV1 but the encoder is slooooooooow.)

[nwallin]

> (I would upload as AV1 but the encoder is slooooooooow.)

If you're using libaom, try switching to libsvtav1. It's still slow, but it's slooow instead of slooooooooow.

[booi]

Also the fact that hardware-accelerated AAC and even full AAC offload is ubiquitous in modern-ish hardware. I think my rice cooker can play AAC audio

[lesscraft]

No one really offloads AAC, apart from Apple. Opus can be decoded on very cheap microcontrollers entirely in software using the reference library.

[AnggaSP]

There absolutely does, Android did with low power audio. They even goes a step further by offloading bluetooth processing into DSP.

I’m not in this space anymore but as of Android 5-6 era aac and bt is offloaded to hexagon dsp on qualcomm device.

[ZeroGravitas]

You might be referring to this but on top of hardware decode some Bluetooth setups can send the actual AAC file to the headphones and decode it there.

Traditionally Bluetooth audio meant decoding and reencoding it into a crappier codec before transmission. So it's an efficiency and quality win.

I think some Google Pixel Bud Pro earphones do this for Opus but that is rarer (there's a few other codecs that have been done like this over the years by different manufacturers).

[philistine]

On a microcontroller doing nothing else sure. But on a phone, a tablet, a laptop, you absolutely want hardware decode to preserve your battery life.

[nulld3v]

That's their point though. Basically no modern phone/laptop/tablet other than Apple offloads audio decoding (of any codec) to hardware. You can check this on Android phones by installing the Codec Info app.

[coldtea]

Snapdragon chips do (used in many/most androids), Samsung own exynos also does iirc.

If the OS/platform doesn't use it that could be another thing, but those chips do offer audio coded decoding, including aac

[philistine]

Yeah no. All chips in computers, tablets, etc. have hardware decode. Intel chips have hardware decode. AMD, Arm, Raspberry Pi, what have you.

[cogman10]

Audio decode is extremely cheap. It's true that a hardware implementation will be more efficient, but really not a whole lot more.

[rasz]

on a 30MHz microcontroller

[repelsteeltje]

Sample accurate editing is with AAC is a pain though. Especially if you also have video, because frame rates are usually incompatible.

If you want flexibility without fully transcoding both audio and video, Opus is your friend

[ErroneousBosh]

Editing with any playback-only format like AAC or H.264/5 is a pain.

Everyone I've seen complaining about slow choppy playback in DaVinci Resolve appears to be using long-GOP codecs which require a massive amount of processing to decode. It's something like playing out two seconds of video to access every single frame.

[ksncksmckwkf]

Opus is your friend as long as the software you’re using supports it—besides, Apple’s AAC-LC can beat out Opus in low bitrates scenarios.

Whether you like it or not, AAC is still the standard.

[CharlesW]

Plus, at 96+ kbps (assuming an Apple-quality AAC-LC encoder) Opus loses its quality advantage. So at higher bitrates, the benefit of choosing Opus is that encoders/decoders are royalty-free.

[pkulak]

Am I reading that chart wrong? I see Opus ahead across every bitrate.

[CharlesW]

The evaluation tools used are helpful for encoder development, but at best they're imperfect proxies for human perception, and their predictions are often inconsistent with the human experience. I assume that statements like "apparently the best AAC encoder" aren't meant to be taken too seriously, since everybody who does this stuff knows that ABX/MUSHRA tests with real humans is what tells the tale.

On Opus vs. AAC specifically, there's a long history of studies like https://www.researchgate.net/publication/301428302_Perceived... to help answer that question. (There are interesting charts at the top of page 1175.)

[lozf]

That paper was published in 2014. The reference Opus encoder has certainly had a number of improvements that affect sound quality since then, whereas very few AAC implementations have.

[CharlesW]

> The reference Opus encoder has certainly had a number of improvements that affect sound quality since then…

Yes, but not for high-bitrate music applications.¹ For example, Opus 1.2 really improved the quality of music encoding at 32–48 kbps. Opus doesn't have to be great at everything to be great at what it does, just like AAC-LC doesn't have to be. (¹Opus 1.6's experimental Opus HD looks very promising for this!)

Apple's and Fraunhofer's closed-source AAC-LC encoders have seen regular, minor quality tuning, and they benefit from the research and engineering work that have been done for the AAC family of encoders (HE-AAC for bitrates down to ~48 kbps, HE-AAC v2 to 32 kbps, xHE-AAC below that).

[ksec]

>So at higher bitrates, the benefit of choosing Opus is that encoders/decoders are royalty-free.

Not only is the new AAC Encoder also royalty-free, the AAC-LC codec itself has been declared by Redhat as patent free ( all patent expired ).

[someonebaggy]

The RTMP protocol comes from Adobe Flash which only supported a limited set of codecs, the only still useful ones being H264 and AAC. Nobody published the needed protocol extension "enhanced RTMP" until 2022 and it still isn't supported widely. RTMP is not a generic container for any codec, like Mastroska - RTMP is tightly coupled to the codec.

[stefan_]

I think often of how all it would have taken was a bomb for the 10 or so people that years ago at some browser vendor consortium out of pure self centeredness went „nah lets fragment“. We could have saved many many collective years, electricity and eyeballs simply watching the most basic content.

[derf_]

At one point in I think 2012 three of us who normally all live in different countries were riding in the same car in Australia. We advised the driver to be extra careful (she was dating one of us, so incentives were aligned).

But it is nice to hear that you have been thinking of us, too.

[arikrahman]

Took me a second to realize you were talking about the encoder not the model before going into this article

[jck86]

Choosing a lossy audio codec has become such a no brainer. Either use opus and be done with it or if for some reason opus cannot be used then use aac for compatibility with insane high bitrate for good quality without having to do research on what encoder and mode to pick.

Still having a good quality and default aac encoder is great. Though I don't get why it is mainly CBR.

[BoingBoomTschak]

Eh, I prefer Vorbis mostly because it's still competitive at transparent bitrates (esp. with Aotuv patches) and benefits from a much saner volume normalization spec (simply transfer RG 2.0 tags from the FLAC source): Xiph decided to exclude peak information from Opus' spec while adding that weird thing where album gain is stored in the format header and additional track gain in the metadata.

It also uses less battery on my Rockbox'd Clip+.

[jck86]

For replaygain purposes simply ignore the spec and use RG 2.0 tags? That works with Opus too and hardly any players support Opus R128 gain anyway. For very low spec devices Vorbis would do a bit better though. For legacy devices legacy codecs can be a better fit indeed.

But would you really store new material encoded in Vorbis just to be able to play it on an old device? Vorbis can sound fine, even at lower bitrates like 128k or 96k, but Opus would sound much better. So perhaps then use Vorbis at higher bitrates like +192k? I prefer Vorbis to Aac but at that bitrate minor intricacies of the container format become more important than the codec because audio quality wise they are near indistinguishable.

[a1o]

I think the biggest issue with Opus is the problem with its specification being lacking, see:

https://nothings.org/stb/stb_opus.html

This essentially causes opus to never be used in games or in things in stores that may have issues with specific licenses.

[scratcheee]

That’s going a bit far. I’m in the games industry and have used opus regularly, it’s a great codec for games, often the hardware decoding is so restricted that we’re using software regardless so we might as well use something like opus.

The licensing restriction is unfortunate, but only restrictive for those with very specific goals, under normal conditions BSD is a wonderful license for game devs since you’re free to use the code and only have to add an acknowledgement somewhere.

I suppose a public domain game might hit the same limitation, though as a non-lawyer I would guess the chance of anyone with standing trying to sue anyone implementing from this spec is realistically zero (though I don’t fault stb for being unwilling to roll those dice!)

[duskwuff]

> under normal conditions BSD is a wonderful license for game devs since you’re free to use the code and only have to add an acknowledgement somewhere.

And it's not as though libopus is an outlier in using a BSD license. A lot of other commonly used libraries have similar licenses; a few examples that come to mind which are likely to show up in games are zlib, curl, Lua, and SDL.

[chaosharmonic]

libopus isn't even an outlier in using it for a media format specifically. See: everything coming out of the Alliance for Open Media

[a1o]

The game doesn’t have to be publicly licensed, the issue is for a library used by this game - or their engine. This remark is what blocks anyone from Valve making their own opus compatible library to use on their engines and supported libraries from what I could tell.

[kderbe]

This essay says it's not possible to make a public-domain implementation of Opus. But it could be released under BSD (as libopus is), which is fine for games, as evidenced by the Licenses section of the credits in many games.

[ack_complete]

Most games use the sound support that comes with their game engine or choice of sound system, so I don't think the lack of an STB version is an issue. Performance is more of a problem. Audiokinetic, the makers of the popular Wwise audio system, estimate that Opus takes ~3-5x the CPU of Vorbis:

https://www.audiokinetic.com/en/community/blog/a-guide-for-c...

[IshKebab]

He's definitely being way over pedantic. Reading the law like HN programmers imagine it works, rather than how it actually works.

The intent of the legal language in that spec is pretty clearly that you have to use the BSD license if you copy that code, but if you merely read it to understand the spec then you don't.

[upofadown]

The linked article makes the argument that looking at the BSD licensed example code in the RFC that defines Opus would mean that code written based on that understanding would be a derivative work and would have to be BSD licensed. This seems to have something to do with the fact that "clean-room design"[1] is a thing. But as the Wikipedia article points out:

>Clean-room design is usually employed as best practice, but not strictly required by law.

As the article points out, if this was actually true then we could change the licensing on code examples found in RFCs to fix the issue, but there doesn't seem to be any actual issue here. Imagine a world where simply reading some code caused licensing issues...

[1] https://en.wikipedia.org/wiki/Clean-room_design

[account42]

Opus is used in games.

[skydhash]

I would like Opus, but I’m using a subsonic client on iOS and my choice has been Flac (Alac?), MP3, or AAC. Opus wouldn’t play (There are some that supported it, but I didn’t like their UX).

[CharlesW]

You might like Poppy (in beta), which supports all media servers (including OpenSubsonic/Navidrome) and Opus as a first-class music format. https://www.reddit.com/r/PoppyApp/comments/1tiyki0/about_pop...

[lutoma]

You can give Arpeggi a try. It’s still in beta and Testflight only, but already (imo) by far the best iOS app for Navidrome/subsonic servers. It also supports Opus playback on current iOS versions (since Apple added native support for the codec).

[bob1029]

https://en.wikipedia.org/wiki/Opus_(audio_format)#/media/Fil...

[sbseitz]

Most of my collection is Opus 256K, the only downside is support. A lot of tools like Bliss/Roon don't support it :(

[subarctic]

Definitely thought you meant claude opus but now from reading a couple other comments it sounds like you mean something else called opus?

[richrichardsson]

https://opus-codec.org/

Been around a lot longer than Claude Opus.

[Mashimo]

The open source codec opus https://opus-codec.org/comparison/

[palmotea]

> Man what a showcase for Opus this is.

I take it you mean this Opus (https://en.wikipedia.org/wiki/Opus_(audio_format)) not that Opus (https://en.wikipedia.org/wiki/Claude_(AI)).

I read almost all the way through your comment thinking there was a decent probability you were saying this new AAC encoder was written with Claude Opus.

[theandrewbailey]

I've never been AI guy, and have more fascination with audio. I've long stopped being excited when I read "Opus" on HN. It's refreshing when it turns out to be the audio codec.

[Aachen]

To be fair, Opus was never a great name. I always feel the need to specify further when using it outside of a clear context of music codecs (also way before Claude was announced). Love it in every other way though

[pezezin]

No, he was talking about the Opus Dei because this code quality can only be reached by God himself /jk

[numlock86]

Opus, the codec, has been a thing looong time before Claude.

[divan]

why is this downvoted? for people who aren't in audio codec dev space, parent comment reads exactly as 'Opus 4.8 rewrote the codec and blew out all competitors'

[spider-mario]

> for people who aren't in audio codec dev space

You don’t need to be in the audio codec dev space to have heard of one of the most widespread audio codecs of the last decade (used by YouTube, WhatsApp, SoundCloud and added to WebM in 2013).

[divan]

Sure, you could've heard about it outside of that space. Yet, most likely, you have not.

It just feels wrong when HN commenters downvote comments that try to clear up legitimate confusion.