Announcing Bluetooth LE Audio

https://www.bluetooth.com/learn-about-bluetooth/bluetooth-technology/le-audio/

by dsalzman • 7 years ago

90 104 7 years ago

DaniFong2• 7 years ago

really interested in latency here

xnyan2• 7 years ago

It's not mentioned, seeing as this was a press release if it was better than the current standard then one would assume they would have mentioned it. Assuming this is the case, 200-500ms in real world conditions. With super duper non-standard proprietary tech on both ends from vendors like Qualcomm it can be in theory be as as low as 32ms, but in practice I don't see those numbers. New airpods with apple's proprietary tech get mid 100s ms of latency and that is considered pretty good for BT headphones in the real world.

BT5 does make things better if for no other reason than less re-transmits vs 4 in the same conditions.

Kirby645• 7 years ago

Yeah, according to some news articles, I see Airpods Pro have a latency of ~144ms end-to-end. I haven't noticed that latency when I watch videos on my phone... On the other hand, I definitely noticed the latency with a much cheaper pair of true wireless earbuds. They probably had the ~500ms latency you mention.

I wonder how much the real-world latency is. If the codec itself is only adding 20ms, what about the rest of the system?

audunw2• 7 years ago

I don’t know about the specific latency, but I know it’s significantly improved over classic Bluetooth.

DaniFong2• 7 years ago

do i have to invent the system for ~1 ms latency? serious question. needed for music. anyone trying to solve this yet?

chrisco255• 7 years ago

I love the use case of being able to sync with local audio sources, whether in the gym, the airport, a cafe, or a retail store. I wonder if an "audio sink" can then turnaround and rebroadcast the input to a different sink, creating a sort of chain of local communication?

lightedman7• 7 years ago

This literally addresses none of my complaints regarding Bluetooth Audio.

Latency needs to be on the order of single-digit milliseconds. LC3 can achieve around 20. One order of magnitude too high.

Audio needs to not sound like it's being played underwater.

And give me 100 feet of range.

PaulHoule3• 7 years ago

For the 100 feet you need more power, better antennas, and diversity reception at the headphone end.

All of these could be implemented with the old Bluetooth standards but for various reasons, people haven't done it.

I think with BTLE it will be easier for systems like that to operate in an infrastructure mode. That is, really my laptop should stream audio over WiFi, then it goes over Ethernet to one or more hubs near me. That's the way you get to perceived 100% reliability.

ShakataGaNai4• 7 years ago

What is your use case for low latency? I understand that some want it for bluetooth headsets for videogames, where milliseconds mater - but beyond that?

Also what about AptX LL? Or LLAC?

lightedman7• 7 years ago

I play guitar. Timing is absolutely necessary. Anything past 15ms I can perceive and it is highly distracting and off-putting to my internal metronome.

klodolph5• 7 years ago

If you are a musician, try introducing a 10ms or 20ms delay and then play something on piano or guitar. Whether you notice it depends on a ton of factors which I’m not going to get into, but in general, at 10ms the music will feel sluggish and you will have difficulty playing on the beat. This can be verified with ABX tests if you like.

The timing accuracy for professional musicians can approach 1ms under controlled tests. The human auditory system is extremely sensitive to timing differences, among other reasons, because we use these timing differences to localize sound. 10ms is about equivalent to a 3m distance in space. So if you have a 10ms delay on your guitar, it sounds like you are playing a guitar that is 10 feet away from you.

ulfw• 7 years ago

"Audio needs to not sound like it's being played underwater."

What kind of bluetooth have you been using? Modern codecs sound perfectly fine.

monocasa2• 7 years ago

Modern codecs are non standard vendor extensions.

yrro• 7 years ago

My fancy Sony headphones sound great until I need to make a call whereupon they revert to HSP which sounds awful...

Kirby645• 7 years ago

You're asking for a lot of pretty specialized things that don't really address the broader market. If you truly need single-digit ms latency, wired solutions or proprietary wireless is going to be better.

The whole point of codecs is to use less of the incredibly congested 2.4G band and deliver similar performance. There are trade-offs, such as latency, in this case.

Also, range is a component of antenna and power usage, both of which could be tailored to reach 100ft. Problem is, people would prefer smaller antennas and lower power, since 100ft of range is useless to most. There's nothing stopping Bluetooth from doing that though; it's just a matter of the devices that exist today.

Not sure I can help you on the sound quality though. That sounds like a problem with the devices you've been using. AAC or LDAC both sound fine to me... and are available on pretty much any device.

TylerE5• 7 years ago

20ms for playback of media is totally fine.

(Hint: If you're standing on the opposite side of the room from a TV, you're already at about 15ms of latency...sound moves at approx. 1ft per ms)

Many TVs are already delaying the audio by a frame or two anyway due to all the processing they do.

It's a very very different set of requirements than real time recording/instrument playback.

Naac• 7 years ago

That seems like too much.

According to this chart[0], I would say worst case scenario people are sitting 10 feet away from their television. Not to mention 15ms would imply you're 15 feet away, which I don't think is the average room size for most people.

I would average worst case scenario would be 10 feet, so 10ms, and average best case would be 3 ms if you're sitting in front of your computer with speakers.

[0] https://www.crutchfield.com/S-DxEcQ1ASZo9/learn/learningcent...

lightedman7• 7 years ago

"20ms for playback of media is totally fine."

Not when you're wearing headphones and playing along with the music with your guitar. 20ms is more than enough to throw off even the most professional musician's timing. It's enough to throw off opera orchestral performance (and I've had it happen performing at Forrest Lawn Glen Avon near Walt Disney's tomb.)

This is why I'm still using wired headphones. Latency is unacceptable in my hobbies.

audunw2• 7 years ago

Sounds like you want a magic solution. At least if you don’t want to compromise on anything else such as distortion due to packet loss and power consumption. Bluetooth Audio is not designed for your use case. You’ll just have to deal with that.

klodolph5• 7 years ago

I’m really looking forward to a new range of incompatibilities between Bluetooth audio devices, as well as the new complications this introduces into the Bluetooth software stack.

jdietrich2• 7 years ago

LE Audio is Multi-Stream

Praise be to the heavens - we can finally have Bluetooth headphones that don't revert to low-bitrate mono if the microphone is active.

daze42• 7 years ago

YES! This has been bothering me for so long. I'm shocked it's taken them this long to iron it out. I hope the device manufacturers implement it soon.

Edit: on second read, I'm not so sure LE Audio will address this issue.

"Multi-Stream Audio will enable the transmission of multiple, independent, synchronized audio streams between an audio source device, such as a smartphone, and one or more audio sink devices."

This sounds like it's referring to stereo or other multichannel audio, not bidirectional. Hopefully I'm wrong.

jdietrich2• 7 years ago

on second read, I'm not so sure LE Audio will address this issue.

The current issue is that headsets only support a single stream and A2DP isn't bidirectional, so the connection has to revert to the low-fidelity Headset Profile. Multistream means that each stereo channel and the microphone should operate fully independently. If this doesn't fix the issue, then it'll be a spectacularly boneheaded error, even by the standards of the Bluetooth SIG.

ShakataGaNai4• 7 years ago

The "Broadcast" mode is really an interesting concept - depending on the available range. There are a lot of potential uses for this technology beyond the basic. Of course "I can share my headphones with you" is great, in the day in age of watching moves on iPads in say a plane. However I think in a business setting the broadcasts could be used for all sorts of cool bits.

Remember the TV's in airports running news on mute? Now just tune in your broadcast bluetooth!

Museums and art galleries don't need to provide audio guide devices - just tune into the broadcast. Might even be able to do multiple broadcasts, one for each language, for each station.

Silent discos without the need for custom headphones.

Mass transit (trains, buses, subway stations, airport) could broadcast announcements, the same way they do now over speakers, so those who have a hard time hearing the announcements (or just have headphones in anyways) could actually hear them. This would be particularly great if you could listen to your own personal audio source (ex music) AND get the BT broadcasted announcements.

klodolph5• 7 years ago

Mass transit (trains, buses, subway stations, airport) could broadcast announcements, the same way they do now over speakers, so those who have a hard time hearing the announcements (or just have headphones in anyways) could actually hear them.

These are often transmitted over audio induction loop already.

ShakataGaNai4• 7 years ago

Ah, fair point. As I'm not hard of hearing I don't think about those technologies much.

However as an "regular person", I would like to be able to hear the audio announcements on the local train system (BART). The trains tends to be extremely loud so in-ear/ANC headphones are almost required for ear protection. ANC + Movie/Music = No idea what is going on or why.

snarf212• 7 years ago

Agreed, plus everyone at the bar can listen to whichever game they want without annoying everyone else. That is killer.

Someone12342• 7 years ago

So you go to a bar, don't talk to people, and listen to a specific game solo. Why not just stay at home? The other examples named above make sense, this one seems like a stretch.

The whole purpose of going to the bar is to be around other people, the whole point of watching sports at a bar is to enjoy it together.

jonny_eh• 7 years ago

Tune into the arcade game or pinball machine you're playing.

rwem4• 7 years ago

The killer application for this technology is a bicycle bell you can use to break the trance of phone-staring pedestrians who are randomly staggering down the pavement.

lxe2• 7 years ago

I don't think this is how it will work. Broadcasting won't immediately interrupt others' connections.

PaulHoule3• 7 years ago

See

https://blogs.findlaw.com/law_and_life/2013/08/legal-to-ride...

gumby2• 7 years ago

Once you can do that the killer app will be intrusive ads.

And those people who drive down the street blasting loud music (err, I mean "sharing their stereos")? They'll be able to share directly to the people on the sidewalk!

(I loved your comment -- I think we both know this won't be supported).

Lammy3• 7 years ago

A bicycle is a road vehicle. You shouldn’t be riding on the sidewalk.

ortusdux• 7 years ago

It would be great for the array of TV's at the gym. Mine currently has a headphone jack on each treadmill with a keypad that you can tune into your preferred channel. I've taken to watching Netflix with Bluetooth head phones vs trying to use a wired pair while I run.

wikibob• 7 years ago

3.5mm Bluetooth Transmitter

https://www.amazon.com/MP3-Player-Bluetooth-Transmitters/b?i...

nmstoker• 7 years ago

The mass transit point would get my vote, specifically so you can ignore them more effectively than is currently possible (even with noise cancelling headphones).

On various modes of UK public transport, I regularly have to listen to people who shouldn't ever be given access to a PA system struggling to complete their obligatory yet pointless announcements.

There was a period a couple of years back when Waterloo station was going to have work done over the summer and there were times in the winter and spring months leading up to it when they would announce this at EVERY single station stop, day in day out on the way in and the way home. LE Audio would have been heaven for a scenario like that!

rlpb• 7 years ago

I wonder how this will fare with spam. If I'm to have autoconnection, for example, then the broadcaster will need to be authenticated.

I can imagine a scenario where I autoconnect to my public transit provider's broadcasts to hear announcements, but an unscrupulous advertiser spoofs the broadcast to spam me.

If there's no authentication or anyone can just broadcast, then I think the spam problem will make broadcast reception unusable in public spaces.

nwah12• 7 years ago

Is LC3 superior to existing codecs like Opus?

0-_-0• 7 years ago

Opus is not low complexity

nwah12• 7 years ago

Found this:

LC3 at 32 kbps (LC3 32) provides significantly better audio quality than Opus-CELT at 32 kbps and complexity level 0 (OPUS_v114_c0 and COPUS_v114_c0).

https://www.etsi.org/deliver/etsi_tr/103500_103599/103590/01...

rasz4• 7 years ago

opus_256k can decode in real time on ~40MHz arm9 from 1999, or 16MHz DSP core https://www.synopsys.com/dw/ipdir.php?ds=arc_audio_opus_code...

The_rationalist2• 7 years ago

I don't get it, if I watch an opus music on YouTube, will my headphone transmute opus into LC3? Why this indirection and overcompression? Latency shouldn't exist at all with opus anyway, YouTube just has to send cached audio to the headphone.

Kirby645• 7 years ago

Because that requires a Bluetooth processor that can decode Opus. Also, it's a lot less simple than that. You aren't sending the raw audio file to the Bluetooth chip, you're sending an internal audio stream which is already getting converted anyways.

The path is almost always: input audio stream -> decode into raw PCM/PDM/TDM/whatever -> convert to whatever sample rate you're using internally -> move it to your output via some sort of audio bus -> output converts to whatever format IT needs (for bluetooth, this would be into packets to send over bluetooth... for a speaker driver, this would be into signals that drive an actual speaker)

Even if you could send Opus directly, I guarantee there's a reason that they went through the effort of developing an entirely new codec. If Opus met all their needs right off the shelf, then you bet they would spend the effort to use what already exists.

There probably is some sort of latency compensation that you could perform to alleviate this for video content (e.g., most receivers have a delay option to compensate for TV latency), but this falls apart for any instantaneous audio (e.g. button presses, video games, or other dynamic content). You want everything to run as quickly as possible.

krastanov• 7 years ago

Will phones/computers that have bluetooth 4 or 5 be able to transmit bluetooth LE audio? Is it just a BLE feature that can be added in software, or is it a completely new standard?

makarhum2• 7 years ago

Most likely no. LE Audio requires controller support for Isochronous channels which is major part of Bluetooth 5.2. Usually firmware updates for bt chipsets are more like bug fixes than new features.

rasz4• 7 years ago

Not to mention majority of devices on the market already ship from the factory with depleted firmware update slots. https://www.youtube.com/watch?v=4_nI9ok7iQg

davefp• 7 years ago

Just yesterday I was discussing how one might do live translation for someone speaking to a multi-lingual group, for example a tour guide at a museum. The broadcast features mentioned here would make things way easier, and people could use their own headphones to boo.

jagged-chisel• 7 years ago

I personally would not have predicted something like this was needed. How long has this been in the works? Now that I can see how useful this is, I'm amazed this didn't happen much sooner. Is this one case where "we" knew we needed it, but the tech just wasn't available?

dsteinman• 7 years ago

Bluetooth LE uses substantially less battery than older Bluetooth devices do. It makes a big difference for anything that's battery powered. I was really bummed when I found out BLE didn't support audio at all.

I can't quite tell from the website, but I'm assuming we will need new BT antennas BLE Audio support before we can use it, which sadly means yet another generation of computers & smartphones have to come out before this can become ubiquitous.

lxe2• 7 years ago

Where can I find more about LC3 codec? What about LE audio specs? Is this open source or do they sell licenses for this?

xd1936• 7 years ago

I too am interested in this. The only thing I've been able to dig up so far is that it's a new codec, built for BT LE Audio, that seems to have been designed by Synopsys[1]

1. https://markets.businessinsider.com/news/stocks/synopsys-rel...

makarhum2• 7 years ago

Specifications will be published during the first half of 2020. Afaik specs will be public but some kind of qualification may be required.

The_rationalist2• 7 years ago

Why do we need another codec than opus? Is it complementary?

Also why do Bluetooth create a latency, this is pure nonsense. YouTube has cached the video so instead of sending in real time audio to my headphone, why can't the YouTube app send cached audio too in order to have zero latency?

jimmyspice• 7 years ago

Interesting idea! This introduces the same problems that an online game suffers though. 90% of the time you can predict successfully what is playing, but as soon as one scrubs, or pauses the video, the signal already sent to the headphones would be out of sync. Not sure how that is fixed without delaying the video also.

If it could recover fast enough to play the right audio in time, then it would seem that bluetooth is already low latency enough to play in real time anyway? Or am I missing something.

emptybits• 7 years ago

Scenario: Two people, quiet room, watching TV, each wearing their own Bluetooth headphones to listen together. As I understand Bluetooth audio standards, until now, this is impossible without additional hardware to split the source and allow multiple 1:1 pairings. Ugh.

Will this seemingly simple scenario be handled by Bluetooth LE Audio? I'm reading about its one-source:multi-sink capability with some hope.

tjoff• 7 years ago

Man I hope they have a good plan for fixing pairing with all the millions of different devices.

Either that or the whole ordeal will be hilarious to watch.

andor• 7 years ago

Bluetooth LE is a completely different protocol and fixes the pairing issues.

randyrand• 7 years ago

Odd that they don't include power consumption specs.

more_corn• 7 years ago

In slightly related news, does anyone know where in the Bluetooth spec soft power buttons are required? (press for three seconds to turn on, oh wait it was already on, not it's off, press for three more seconds...) My biggest complaints with Bluetooth are exacerbated by the fact that it's not possible to flick a power button off and back on again.

Announcing Bluetooth LE Audio

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