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Improve Bluetooth audio latency on HifiBerryOS

Hammerfet

May 23, 2020 10:11

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Hi there,

I’m trying to figure out if there’s any way to reduce the Bluetooth audio latency when using HifiBerry OS. I’ve tried several Bluetooth sources and they all seem to result in around 300 - 400ms delay in the audio. Side note, it seems to increase to almost 1s sometimes, and a reboot is needed to get it back down to 300ms. Current setup is:

• RPi 3A+
• DAC+ DSP board.
• HifiBerry OS 20200424

I currently have everything disabled other than Airplay and Bluetooth. These are the only services I plan to use. Airplay seems to work great with unnoticeable delay. It’s just the Bluetooth. 

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8 comments

• 0
  
  HiFiBerry team May 23, 2020 13:54

  These are not bad delays for Bluetooth. Bluetooth is a low-bandwidth connection. Buffering is needed to make sure it works reliably.

• 0
  
  Fredrik Fyksen Lund January 16, 2021 18:13

  You could edit the file /usr/lib/systemd/system/bluealsa.service , and add --pcm-buffer-time=0.1

  Ofcourse you could adjust it if you get stutters.

  The whole file would look like this:

  [Unit]
  Description=BlueALSA
  Requires=a2dp-agent.service
  After=a2dp-agent.service
  
  [Service]
  ExecStartPre=/opt/hifiberry/bin/bootmsg "Starting bluealsa"
  ExecStart=/usr/bin/bluealsa -i hci0 -p a2dp-sink --a2dp-volume --pcm-buffer-time=0.1
  RestartSec=5
  Restart=always
  TimeoutStopSec=10
  
  [Install]
  WantedBy=multi-user.target

• 0
  
  Gustav January 21, 2021 20:42

  I have a setup with the beocreate and berry 4B and get around 2 to 3 sec latency with bluetooth and airplay. Are there any options to reduce the latency?
  Or do I have to drill a hole into the speaker to get to the toslink jack? Do this reduce latency at all? HiFiBerry team

• 0
  
  HiFiBerry team January 21, 2021 20:44

  I recommend to avoid BT whenever possible. Can't say anything about reducing latency. You might check with the blues-alsa developers, maybe somebody can give you some tips:
  https://github.com/Arkq/bluez-alsa

• 0
  
  Gustav January 21, 2021 20:57

  AirPlay has around the same latency for me. But is optical better?

• 0
  
  HiFiBerry team January 22, 2021 06:38

  Yes, latency on the optical iinput is a few milliseconds (depending on the DSP program)

• 0
  
  HiFiBerry team January 22, 2021 07:12

  BTW: Airplay is able to do a few 100ms easily. Unfortunately IOS devices don't allow users to set this lower and use something in the range of 2s.

  Edited by HiFiBerry team January 22, 2021 07:13
• 0
  
  Bernhard2016 November 26, 2023 12:03

  I tried from Frederik's proposal ("edit the file /usr/lib/systemd/system/bluealsa.service").
  However then I couldn't connect to bluetooth anymore.

  According to the bluealsa documentation I changed the parameters a bit and added the following instead:
   --pcm-buffer-time=100000 --pcm-period-time=20000
  However again I couldn't connect to bluetooth anymore.

  Bluealsa doc: https://github.com/Arkq/bluez-alsa/blob/master/doc/bluealsa-aplay.1.rst