Low latency options for Bluetooth?

Low latency options for Bluetooth?

[Philipp Haselwarter]

Hi,

Legacy bluetooth codecs have a latency of ~200 ms or more, which creates
a noticeable lag when watching videos or during voice calls.

The AptX Low Latency (LL) codec can provide a stable connection with at
most 40 ms of latency.

- Is there a way to get AptX LL to work on Linux?
- Are there alternatives for a low latency Bluetooth connection?

PS: I hope this is a legitimate place for this question; I couldn't find
a bluez-user mailing list.

Cheers,
-- 
Philipp G. Haselwarter

Re: Low latency options for Bluetooth?

[Marcel Holtmann]

Hi Philipp,

> Legacy bluetooth codecs have a latency of ~200 ms or more, which creates
> a noticeable lag when watching videos or during voice calls.
> 
> The AptX Low Latency (LL) codec can provide a stable connection with at
> most 40 ms of latency.
> 
> - Is there a way to get AptX LL to work on Linux?
> - Are there alternatives for a low latency Bluetooth connection?

with BlueZ for Android we actually had AptX working (given CSR provided you with a correct binary).

Regards

Marcel

Re: Low latency options for Bluetooth?

[Luiz Augusto von Dentz]

Hi Marcel, Philipp,

On Wed, Apr 18, 2018 at 9:42 AM, Marcel Holtmann <marcel@holtmann.org> wrote:
> Hi Philipp,
>
>> Legacy bluetooth codecs have a latency of ~200 ms or more, which creates
>> a noticeable lag when watching videos or during voice calls.
>>
>> The AptX Low Latency (LL) codec can provide a stable connection with at
>> most 40 ms of latency.
>>
>> - Is there a way to get AptX LL to work on Linux?
>> - Are there alternatives for a low latency Bluetooth connection?
>
> with BlueZ for Android we actually had AptX working (given CSR provided you with a correct binary).

There is a pretty old patch for PulseAudio that enables AptX:

https://build.tizen.org/package/view_file/Tizen/pulseaudio/0020-add-bluetooth-a2dp-aptx-codec-support-samsung.patch?expand=1

It doesn't have the actual AptX library, which I guess cannot be
distributed under the same license. We could perhaps have OPUS (which
should perform quite well) instead which should be available in all
distros already, that said no headset or phone would support it
initially, though it wouldn't be a problem for phones to add support
for it since it has been in use in WebRTC, youtube, skype, etc.

> Regards
>
> Marcel
>
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-- 
Luiz Augusto von Dentz

Re: Low latency options for Bluetooth?

[Marcel Holtmann]

Hi Luiz,

>>> Legacy bluetooth codecs have a latency of ~200 ms or more, which creates
>>> a noticeable lag when watching videos or during voice calls.
>>> 
>>> The AptX Low Latency (LL) codec can provide a stable connection with at
>>> most 40 ms of latency.
>>> 
>>> - Is there a way to get AptX LL to work on Linux?
>>> - Are there alternatives for a low latency Bluetooth connection?
>> 
>> with BlueZ for Android we actually had AptX working (given CSR provided you with a correct binary).
> 
> There is a pretty old patch for PulseAudio that enables AptX:
> 
> https://build.tizen.org/package/view_file/Tizen/pulseaudio/0020-add-bluetooth-a2dp-aptx-codec-support-samsung.patch?expand=1
> 
> It doesn't have the actual AptX library, which I guess cannot be
> distributed under the same license. We could perhaps have OPUS (which
> should perform quite well) instead which should be available in all
> distros already, that said no headset or phone would support it
> initially, though it wouldn't be a problem for phones to add support
> for it since it has been in use in WebRTC, youtube, skype, etc.

actually it seems FFmpeg has an open source aptX encoder and decoder.

https://patchwork.ffmpeg.org/patch/5879/

https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/aptx.c

So I think someone could extend PA to use FFmpeg’s aptX and just enable aptX for all devices.

Regards

Marcel

Re: Low latency options for Bluetooth?

[Luiz Augusto von Dentz]

Hi Marcel,

On Tue, Apr 24, 2018 at 10:01 AM, Marcel Holtmann <marcel@holtmann.org> wro=
te:
> Hi Luiz,
>
>>>> Legacy bluetooth codecs have a latency of ~200 ms or more, which creat=
es
>>>> a noticeable lag when watching videos or during voice calls.
>>>>
>>>> The AptX Low Latency (LL) codec can provide a stable connection with a=
t
>>>> most 40 ms of latency.
>>>>
>>>> - Is there a way to get AptX LL to work on Linux?
>>>> - Are there alternatives for a low latency Bluetooth connection?
>>>
>>> with BlueZ for Android we actually had AptX working (given CSR provided=
 you with a correct binary).
>>
>> There is a pretty old patch for PulseAudio that enables AptX:
>>
>> https://build.tizen.org/package/view_file/Tizen/pulseaudio/0020-add-blue=
tooth-a2dp-aptx-codec-support-samsung.patch?expand=3D1
>>
>> It doesn't have the actual AptX library, which I guess cannot be
>> distributed under the same license. We could perhaps have OPUS (which
>> should perform quite well) instead which should be available in all
>> distros already, that said no headset or phone would support it
>> initially, though it wouldn't be a problem for phones to add support
>> for it since it has been in use in WebRTC, youtube, skype, etc.
>
> actually it seems FFmpeg has an open source aptX encoder and decoder.
>
> https://patchwork.ffmpeg.org/patch/5879/
>
> https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/aptx.c
>
> So I think someone could extend PA to use FFmpeg=E2=80=99s aptX and just =
enable aptX for all devices.

Interesting, I guess we could do that, most likely it will be hard for
distros since they don't normally ship with libavcodec since other
codecs might not be 'free', but I guess users may be able to install
that by themselves.

--=20
Luiz Augusto von Dentz