Re: Fwd: Bluetooth Audio stuttering when more than 4 ios devices with bluetooth devices in close proximity
Re: Fwd: Bluetooth Audio stuttering when more than 4 ios devices with bluetooth devices in close proximity
- Subject: Re: Fwd: Bluetooth Audio stuttering when more than 4 ios devices with bluetooth devices in close proximity
- From: taykh--- via Bluetooth-dev <email@hidden>
- Date: Sun, 25 Oct 2020 09:46:56 +0800
The connection is 1 iOS device to 1 bluetooth device. There won't be
multiple connection to one sink in our case.
In https://developer.apple.com/documentation/corebluetooth, I see
CBError inside Core Bluetooth API. I am not sure whether iOS app able to
capture Baseband CRC error using CBError but we will ask the developer
to try it out.
Thank you Samuel for your input.
Regards
Paul Tay
From: JOHN WESTING <email@hidden>
Date: Sat, Oct 24, 2020 at 11:45 PM
Subject: Re: Bluetooth Audio stuttering when more than 4 ios devices
with bluetooth devices in close proximity
To: <email@hidden>
Cc: <email@hidden>, <email@hidden>,
<email@hidden>
What’s your pico net look like? For 1 connection it’s optimal for
the audio source to be the master. For multiple connections to one
sink, it’s better for the sink to be master. iOS devices do all they
can to become master, especially in newer releases of iOS, since about
3 years now.
Samuel
On Sat, Oct 24, 2020 at 9:20 AM taykh--- via Bluetooth-dev
<email@hidden> wrote:
Hello everyone,
We encountered a serious bluetooth audio stuttering problem that
need
expert advice. We are using Microchip BM62 solution which has Ble
and
A2DP.
Scenario is this:
Our customer has started roadshows and they put up at least 4
bluetooth
products for demo in each location. Demo would last for hours, with
each
product connected and bluetooth paired to an iOS device; with iOS
app
running and controlling the product through Ble and playing music.
And
all are in close proximity to one another.
What happen is at least 1 iOS device playing music to bluetooth
device
start to audio stutter for no particular reason. It can happen just
a
short moment to hours after music played. Sometime audio stuttering
would disappear and normal music continue.
Our supplier performed bluetooth sniffing to capture the protocols
using
bluetooth protocol analyzer. We have the cfa files. I did not
attached
to the email because the file size is greater than 200MB. Please let
us
know if anyone need to the file. We will send to him.
We use ComProbe software to view to result.
Result showed that baseband layer have multiple CRC errors. In
Message
Sequence Chart, where frame consists CRC Error, it showed flow from
BB_M
to BB_S. See image
http://www.raynet.com.sg/bluetooth/music_break_v1_APP_music_message_sequence_chart.png
And using Audio Expert System analyzer, we can see visually the
break or
absent of audio protocol and even hear the audio stuttering. See
image
http://www.raynet.com.sg/bluetooth/music_break_v1_APP_music_audio_expert_system.png
Our supplier is unable to conclude the cause to the problem. Or
solution
to audio stuttering.
Therefore, we wrote to seek for expert advise to help to solve this
audio stuttering problem.
We suspect there is RF interference - multiple iOS devices usage
audio
stuttering would occur. Single iOS device usage does not see the
problem.
What puzzle us is that multiple android devices usage also does not
see
the problem.
We hope Apple experts could advise us on this.
Lastly, is it possible to get an event when bluetooth baseband CRC
error
occur? We want to see whether iOS app could capture this event and
subsequent stop music when audio stuttering happen.
Thank you.
Regards,
Paul Tay
Raynet Technologies Pte Ltd
Singapore
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