Set up raspberry pi 3 as bluetooth sink (raspbian buster)

raspian_bluetooth_sink.md

If you want to use pulseaudio, see BaReinhard's repo.

If you want to use bluealsa and avoid pulseaudio, keep reading.

So far this solution has two problems I haven't solved:

• A ~450 ms delay (which can be compensated for in pavucontrol on the client)
• If more than one source connects at the same time bluealsa-aplay crashes and bluealsa also needs restarting

If you have pulseaudio installed, make sure /etc/pulse/default.pa has the following two lines commented out and restart pulseaudio:

#load-module module-bluetooth-policy

#load-module module-bluetooth-discover

Install bluealsa:

apt install bluealsa

Get bluealsa to autostart like so:

https://github.com/Arkq/bluez-alsa/wiki/Systemd-integration

But add the following line to /etc/default/bluealsa:

LIBASOUND_THREAD_SAFE=0

Get bluealsa-aplay to restart by adding /etc/systemd/system/bluealsa-aplay.service:

[Unit]
Description=Bluealsa-aplay daemon
Documentation=https://github.com/Arkq/bluez-alsa/
After=bluealsa.service
Requires=bluealsa.service
StopWhenUnneeded=true

[Service]
Type=simple
Environment="LIBASOUND_THREAD_SAFE=0"
ExecStart=/usr/bin/bluealsa-aplay 00:00:00:00:00:00

[Install]
WantedBy=multi-user.target

Then:

systemctl daemon-reload
systemctl enable bluealsa-aplay.service
systemctl start bluealsa-aplay.service

In /etc/bluetooth/main.conf:

# Default device class. Only the major and minor device class bits are
# considered. Defaults to '0x000000'.
Class = 0x200414

# How long to stay in discoverable mode before going back to non-discoverable
# The value is in seconds. Default is 180, i.e. 3 minutes.
# 0 = disable timer, i.e. stay discoverable forever
DiscoverableTimeout = 0

# How long to stay in pairable mode before going back to non-discoverable
# The value is in seconds. Default is 0.
# 0 = disable timer, i.e. stay pairable forever
PairableTimeout = 0

Now you'll need a script to auto-trust connecting clients.

Use this script to auto-trust:

/etc/init.d/bluetooth-agent

which needs these two files:

/usr/local/bin/simple-agent.autotrust

/usr/local/bin/bluezutils.py

Copy these to your local filesystem, then make it auto-start:

git clone https://github.com/BaReinhard/Super-Simple-Raspberry-Pi-Audio-Receiver-Install
cd Super-Simple-Raspberry-Pi-Audio-Receiver-Install/
sudo cp -a init.d/bluetooth-agent /etc/init.d/
sudo cp -a usr/local/bin/simple-agent.autotrust /usr/local/bin/
sudo cp -a usr/local/bin/bluezutils.py /usr/local/bin/
sudo update-rc.d bluetooth-agent defaults

Make sure you have python 2.7 installed (yeah, i know...) and remove the reference to pulseaudio at the top of bluetooth-agent.

If using an external sound card, set default alsa sound card by first listing which cards are present:

cat /proc/asound/cards

Noting which number your preferred card has (probably 1) and then creating /etc/asound.conf with:

pcm.!default {
    type hw
    card 1
}

ctl.!default {
    type hw           
    card 1
}

Changing the card number if needed.

To set audio volume on boot use alsamixer to change it and then save with:

 sudo alsactl store

It should now all work. However if you're sending from a pulseaudio client then it might not work. Stop bluealsa-aplay and start it manually:

sudo bluealsa-aplay 00:00:00:00:00:00

Then try to play from the client again and if you get this output:

bluealsa: Unsupported RTP payload type: 1

Then you've run into this bug in the pulseaudio client.

It's been fixed, but as of Ubuntu 18.04 the bug is still there. There's a work-around but it requires recompiling bluez-alsa (bluealsa).

Here's how to recompile with the workaround:

Add this line to /etc/apt/sources.list:

# for libfdk-aac-dev
deb http://www.deb-multimedia.org/ buster main non-free

Then run:

gpg --keyserver pool.sks-keyservers.net --recv-keys 5C808C2B65558117
gpg --armor --export 5C808C2B65558117 | apt-key add -
apt update
apt install autoconf libtool libasound2-dev libbluetooth-dev libdbus-1-dev libfaad-dev libglib2.0-dev ofono-dev libsbc-dev libfdk-aac-dev
git clone https://github.com/Arkq/bluez-alsa
cd bluez-alsa/
autoreconf --install
mkdir build && cd build
../configure --enable-aac --enable-ofono --enable-debug --disable-payloadcheck
make
make install
# restart everything