Pipewire

Handy link (thanks archetech on #lfs-support): ​https://wiki.gentoo.org/wiki/PipeWire
It has some indications for SysV (OpenRC startup).

Replace Pulseaudio

With Wireplumber, Pipewire can function as a drop-in replacement of Pulseaudio:

• On systemd:

  sudo systemctl --global enable pipewire-pulse.socket
  sudo systemctl --global disable pulseaudio
  

(For some reason enabling the .socket unit works fine for me, but enabling the .service unit causes the camera not found. Maybe a race condition.)

• On Sysv: add to /usr/bin/pipewire-launcher.sh (after pipewire and before wireplumber):

  exec /usr/bin/pipewire -c pipewire-pulse.conf &
  sleep 1
  

  then move away the file /etc/xdg/autostart/puleaudio.desktop, and change autospawn to "no" in /etc/pulse/client.conf (uncomment it, of course).

• On both systemd and sysv: disable the XDG autostart of traditional PulseAudio daemon

sudo sed '2i exit # nouse' -i /etc/xdg/Xwayland-session.d/00-pulseaudio-x11
sudo sed '$a Hidden=true'  -i /etc/xdg/autostart/pulseaudio.desktop

If PulseAudio is upgraded, do this again.

(Without this my system was running no-sound for 30 seconds after login.)

• Then logout and login again.

Use Pipewire for ALSA-based applications

If Pipewire is running, it will occupy the sound card device and an ALSA-based application cannot use the card at the same time. To work around the issue, tell alsa-lib to use a virtual device provided by Pipewire:

sudo install -vdm755 /etc/alsa/conf.d
sudo ln -sfvr /usr/share/alsa/alsa.conf.d/99-pipewire-default.conf /etc/alsa/conf.d

Bluetooth LDAC support

Install ldacBT before building Pipewire. The link to ldacBT is available on the book page. Installation process of ldacBT:

mkdir build; cd build
cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr
make
# no test suite available
sudo make install

Libcamera support

GNOME/Snapshot (a replacement for Cheese) needs a functional pipewire daemon (i. e. requiring wireplumber) built with libcamera.

We can use v4l-utils instead of libcamera. This section only remains here for reference.

libcamera dependencies are listed at ​https://libcamera.org/getting-started.html. Everything required or recommended is in BLFS, except a Python module named ply.

Install ply (​https://files.pythonhosted.org/packages/source/p/ply/ply-3.11.tar.gz):

pip3 wheel -w dist --no-build-isolation --no-deps --no-cache-dir $PWD
sudo pip3 install --no-index --find-links=dist --no-cache-dir --no-user ply

There is no website for libcamera release tarballs. Clone the git repository and checkout the latest release tag:

git clone https://git.libcamera.org/libcamera/libcamera.git
git checkout v0.1.0

Now install it:

mkdir build
cd build
meson setup --prefix=/usr --buildtype=release --wrap-mode=nodownload -Dwerror=false
ninja
sudo ninja install

Then (re)build pipewire and libcamera should be automatically detected and enabled.