Currently, in a default installation of Debian with the GNOME desktop, Bluetooth headphones that require the AAC codec¹ cannot be used. As the Debian wiki outlines, using the AAC codec over Bluetooth, while technically supported by PipeWire, is explicitly disabled in Debian at this time. This is because the fdk-aac library needed to enable this support is currently in the non-free component of the repository, meaning that PipeWire, which is in the main component, cannot depend on it.

How to Fix it Yourself

If what you, like me, need is simply for Bluetooth Audio to work with AAC in Debian’s default desktop environment², then you’ll need to rebuild the pipewire package to include the AAC codec. While the current version in Debian main has been built with AAC deliberately disabled, it is trivial to enable if you can install a version of the fdk-aac library.

I preface this with the usual caveats when it comes to patent and licensing controversies. I am not a lawyer, building this package and/or using it could get you into legal trouble.

These instructions have only been tested on an up-to-date copy of Debian 12.

1. Install pipewire’s build dependencies

   sudo apt install build-essential devscripts
   sudo apt build-dep pipewire
   

2. Install libfdk-aac-dev

   sudo apt install libfdk-aac-dev
   

   If the above doesn’t work you’ll likely need to enable non-free and try again

   sudo sed -i 's/main/main non-free/g' /etc/apt/sources.list
   sudo apt update
   

   Alternatively, if you wish to ensure you are maximally license-compliant and patent un-infringing³, you can instead build fdk-aac-free which includes only those components of AAC that are known to be patent-free³. This is what should eventually end up in Debian to resolve this problem (see below).

   sudo apt install git-buildpackage
   mkdir fdk-aac-source
   cd fdk-aac-source
   git clone https://salsa.debian.org/multimedia-team/fdk-aac
   cd fdk-aac
   gbp buildpackage
   sudo dpkg -i ../libfdk-aac2_*deb ../libfdk-aac-dev_*deb
   

3. Get the pipewire source code

   mkdir pipewire-source
   cd pipewire-source
   apt source pipewire
   

   This will create a bunch of files within the pipewire-source directory, but you’ll only need the pipewire-<version> folder, this contains all the files you’ll need to build the package, with all the debian-specific patches already applied. Note that you don’t want to run the apt source command as root, as it will then create files that your regular user cannot edit.

4. Fix the dependencies and build options To fix up the build scripts to use the fdk-aac library, you need to save the following as pipewire-source/aac.patch

   --- debian/control.orig
   +++ debian/control
   @@ -40,8 +40,8 @@
                modemmanager-dev,
                pkg-config,
                python3-docutils,
   -               systemd [linux-any]
   -Build-Conflicts: libfdk-aac-dev
   +               systemd [linux-any],
   +               libfdk-aac-dev
    Standards-Version: 4.6.2
    Vcs-Browser: https://salsa.debian.org/utopia-team/pipewire
    Vcs-Git: https://salsa.debian.org/utopia-team/pipewire.git
   --- debian/rules.orig
   +++ debian/rules
   @@ -37,7 +37,7 @@
    		-Dauto_features=enabled \
    		-Davahi=enabled \
    		-Dbluez5-backend-native-mm=enabled \
   -		-Dbluez5-codec-aac=disabled \
   +		-Dbluez5-codec-aac=enabled \
    		-Dbluez5-codec-aptx=enabled \
    		-Dbluez5-codec-lc3=enabled \
    		-Dbluez5-codec-lc3plus=disabled \
   

   Then you’ll need to run patch from within the pipewire-<version> folder created by apt source:

   patch -p0 < ../aac.patch
   

5. Build pipewire

   cd pipewire-*
   debuild
   

   Note that you will likely see an error from debsign at the end of this process, this is harmless, you simply don’t have a GPG key set up to sign your newly-built package⁴. Packages don’t need to be signed to be installed, and debsign uses a somewhat non-standard signing process that dpkg does not check anyway.

1. Install libspa-0.2-bluetooth

   sudo dpkg -i libspa-0.2-bluetooth_*.deb
   

2. Restart PipeWire and/or Reboot

   sudo reboot
   

   Theoretically there’s a set of services to restart here that would get pipewire to pick up the new library, probably just pipewire itself. But it’s just as easy to restart and ensure everything is using the correct library.

Why

This is a slightly unusual situation, as the fdk-aac library is licensed under what even the GNU project acknowledges is a free software license. However, this license explicitly informs the user that they need to acquire a patent license to use this software⁵:

3. NO PATENT LICENSE

NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE. Fraunhofer provides no warranty of patent non-infringement with respect to this software. You may use this FDK AAC Codec software or modifications thereto only for purposes that are authorized by appropriate patent licenses.

To quote the GNU project:

Because of this, and because the license author is a known patent aggressor, we encourage you to be careful about using or redistributing software under this license: you should first consider whether the licensor might aim to lure you into patent infringement.

AAC is covered by a number of patents, which expire at some point in the 2030s⁶. As such the current version of the library is potentially legally dubious to ship with any other software, as it could be considered patent-infringing³.

Fedora’s solution

Since 2017, Fedora has included a modified version of the library as fdk-aac-free, see the announcement and the bugzilla bug requesting review.

This version of the library includes only the AAC LC profile, which is believed to be entirely patent-free³.

Based on this, there is an open bug report in Debian requesting that the fdk-aac package be moved to the main component and that the pipwire package be updated to build against it.

The Debian NEW queue

To resolve these bugs, a version of fdk-aac-free has been uploaded to Debian by Jeremy Bicha. However, to make it into Debian proper, it must first pass through the ftpmaster’s NEW queue. The current version of fdk-aac-free has been in the NEW queue since July 2023.

Based on conversations in some of the bugs above, it’s been there since at least 2022⁷.

I hope this helps anyone stuck with AAC to get their hardware working for them while we wait for the package to eventually make it through the NEW queue.

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