11 ms·

Announcing Bluetooth LE Audio

90 points by dsalzman 7y ago

DaniFong 7y ago
really interested in latency here
- xnyan 7y 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.
  - Kirby64 7y 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?
    - xnyan 7y ago
      Definitely not an expert in BT but I've worked with it on the edges. Bluetooth is the biggest standard I've ever worked with by far in just terms of sheer page count, to say nothing of its complexity. That's just the core spec, not any of the other pieces you need too to make it do useful work. I would not believe the 20ms number without real world performance benchmarks tested in operational conditions for my specific product but if that is what is actually happening, I suspect something with the implementation on the specific platform is to blame - again, the standard is ridiculously complex and hard to implement. It's notoriously bad on android (by bad I mean a dumpster fire) and while windows is actually been making progress, depending on the SoC of the physical adapter your experience can range from great to near android level dumpster fire.
- audunw 7y ago
  I don’t know about the specific latency, but I know it’s significantly improved over classic Bluetooth.
- DaniFong 7y ago
  do i have to invent the system for ~1 ms latency? serious question. needed for music. anyone trying to solve this yet?
chrisco255 7y 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?
lightedman 7y 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.
- PaulHoule 7y 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.
- ShakataGaNai 7y 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?
  - lightedman 7y 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.
    - ShakataGaNai 7y ago
      Sure. Playing music makes sense. I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane". Clearly there are many other use cases.
      - lightedman 7y ago
        "I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane"" At that latency I can see lips move before I hear audio. Very disconcerting.
klodolph 7y 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.
jdietrich 7y 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 7y 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.
  - jdietrich 7y 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.
  - deleted 7y ago
    [deleted]
ShakataGaNai 7y 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.
- klodolph 7y 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.
  - ShakataGaNai 7y 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.
    - klodolph 7y ago
      Maybe it would be possible to receive inductive loop on your headphones.
- 7y ago
nwah1 7y ago
Is LC3 superior to existing codecs like Opus?
- 0-_-0 7y ago
  Opus is not low complexity
  - nwah1 7y 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_103599/103590/01.01.01_60/tr_103590v010101p.pdf https://www.etsi.org/deliver/etsi_tr/103500_103599/103590/01...
    - throw0101a 7y ago
      I'm of the opinion that Codec 2 [0][1] should pause on trying to perform better at lower and lower bit rates, and put some work into higher ones. Getting down to 700 and even 450 b/s is neat and all, but there seems (to me) to be a gap between 4000 and 10000 b/s in the patent-free space. * [0] http://www.rowetel.com/?page_id=452 http://www.rowetel.com/?page_id=452 * [1] https://en.wikipedia.org/wiki/Codec_2 https://en.wikipedia.org/wiki/Codec_2
  - rasz 7y 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_codec https://www.synopsys.com/dw/ipdir.php?ds=arc_audio_opus_code...
    - makomk 7y ago
      For comparison, Synopsys' LC3 codec implementation: https://www.synopsys.com/dw/ipdir.php?ds=arc_lc3_codec https://www.synopsys.com/dw/ipdir.php?ds=arc_lc3_codec It doesn't seem to be a particularly lightweight codec compared to Opus, or particularly performant.
krastanov 7y 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?
- makarhum 7y 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.
  - rasz 7y 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 https://www.youtube.com/watch?v=4_nI9ok7iQg
davefp 7y 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 7y 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 7y 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.
lxe 7y 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 7y 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-releases-industry-s-first-bluetooth-le-audio-codec-for-power-sensitive-audio-and-voice-applications-1028799666 https://markets.businessinsider.com/news/stocks/synopsys-rel...
  - deleted 7y ago
    [deleted]
- makarhum 7y 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_rationalist 7y 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 7y 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 7y 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 7y 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 7y ago
  Bluetooth LE is a completely different protocol and fixes the pairing issues.
randyrand 7y ago
Odd that they don't include power consumption specs.
more_corn 7y 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.

90 points by dsalzman 7y ago

DaniFong 7y ago

really interested in latency here

xnyan 7y 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.
- Kirby64 7y 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?
  - xnyan 7y ago
    Definitely not an expert in BT but I've worked with it on the edges. Bluetooth is the biggest standard I've ever worked with by far in just terms of sheer page count, to say nothing of its complexity. That's just the core spec, not any of the other pieces you need too to make it do useful work. I would not believe the 20ms number without real world performance benchmarks tested in operational conditions for my specific product but if that is what is actually happening, I suspect something with the implementation on the specific platform is to blame - again, the standard is ridiculously complex and hard to implement. It's notoriously bad on android (by bad I mean a dumpster fire) and while windows is actually been making progress, depending on the SoC of the physical adapter your experience can range from great to near android level dumpster fire.
audunw 7y ago
I don’t know about the specific latency, but I know it’s significantly improved over classic Bluetooth.
DaniFong 7y ago
do i have to invent the system for ~1 ms latency? serious question. needed for music. anyone trying to solve this yet?

chrisco255 7y 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?

lightedman 7y 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.

PaulHoule 7y 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.
ShakataGaNai 7y 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?
- lightedman 7y 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.
  - ShakataGaNai 7y ago
    Sure. Playing music makes sense. I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane". Clearly there are many other use cases.
    - lightedman 7y ago
      "I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane"" At that latency I can see lips move before I hear audio. Very disconcerting.

klodolph 7y 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.

jdietrich 7y 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 7y 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.
- jdietrich 7y 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.
- deleted 7y ago
  [deleted]

ShakataGaNai 7y 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.

klodolph 7y 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.
- ShakataGaNai 7y 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.
  - klodolph 7y ago
    Maybe it would be possible to receive inductive loop on your headphones.
7y ago

nwah1 7y ago

Is LC3 superior to existing codecs like Opus?

0-_-0 7y ago
Opus is not low complexity
- nwah1 7y 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_103599/103590/01.01.01_60/tr_103590v010101p.pdf https://www.etsi.org/deliver/etsi_tr/103500_103599/103590/01...
  - throw0101a 7y ago
    I'm of the opinion that Codec 2 [0][1] should pause on trying to perform better at lower and lower bit rates, and put some work into higher ones. Getting down to 700 and even 450 b/s is neat and all, but there seems (to me) to be a gap between 4000 and 10000 b/s in the patent-free space. * [0] http://www.rowetel.com/?page_id=452 http://www.rowetel.com/?page_id=452 * [1] https://en.wikipedia.org/wiki/Codec_2 https://en.wikipedia.org/wiki/Codec_2
- rasz 7y 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_codec https://www.synopsys.com/dw/ipdir.php?ds=arc_audio_opus_code...
  - makomk 7y ago
    For comparison, Synopsys' LC3 codec implementation: https://www.synopsys.com/dw/ipdir.php?ds=arc_lc3_codec https://www.synopsys.com/dw/ipdir.php?ds=arc_lc3_codec It doesn't seem to be a particularly lightweight codec compared to Opus, or particularly performant.

krastanov 7y 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?

makarhum 7y 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.
- rasz 7y 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 https://www.youtube.com/watch?v=4_nI9ok7iQg

davefp 7y 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 7y 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 7y 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.

lxe 7y 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 7y 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-releases-industry-s-first-bluetooth-le-audio-codec-for-power-sensitive-audio-and-voice-applications-1028799666 https://markets.businessinsider.com/news/stocks/synopsys-rel...
- deleted 7y ago
  [deleted]
makarhum 7y 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_rationalist 7y 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 7y 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 7y 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 7y 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 7y ago
Bluetooth LE is a completely different protocol and fixes the pairing issues.

randyrand 7y ago

Odd that they don't include power consumption specs.

more_corn 7y 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.