pw-jack

Run a command with its arguments, using PipeWire

$ pw-jack [command] [argument1 argument2 ...]

$ pw-jack -v [command]

$ pw-jack -r [remote_instance_name] [command]

$ pw-jack -h

pw-jack [OPTIONS] COMMAND [ARGUMENTS...]

-h, --help
    Display help information and exit.

-v, --version
    Display version information and exit.

-L, --library=PATH
    Specify a custom JACK emulation library path to preload instead of the default.

-p, --proxy=PATH
    Connect to a specific PipeWire proxy socket for advanced configurations.

-P, --policy=PATH
    Specify the path to a PipeWire policy file to override default settings.

COMMAND
    The JACK application or command to execute, which will then run under PipeWire's JACK compatibility layer.

ARGUMENTS...
    Optional arguments passed directly to the COMMAND being executed.

pw-jack is a utility that enables JACK (JACK Audio Connection Kit) applications to run seamlessly on a PipeWire sound server. Instead of requiring a separate JACK daemon (like jackd), pw-jack effectively "wraps" a JACK application, making it believe it's interacting with a native JACK server.

It achieves this by preloading PipeWire's JACK emulation library (typically using LD_PRELOAD), which intercepts JACK API calls from the application and translates them into PipeWire equivalents. This allows users to leverage PipeWire's modern architecture, low-latency capabilities, and unified multimedia handling, while still utilizing their existing suite of professional audio software designed for JACK. It simplifies audio setups by consolidating different audio subsystems into one, reducing resource usage and potential conflicts.

While pw-jack offers excellent JACK compatibility, some highly specialized or older JACK applications might exhibit subtle behavioral differences or require specific configurations that are not perfectly emulated. Very demanding low-latency scenarios might also need fine-tuning of PipeWire's configuration (e.g., buffer sizes, sample rates) for optimal performance. It relies on a running and correctly configured PipeWire daemon. Not all obscure JACK API calls might be fully supported, potentially leading to issues with rare software.

pw-jack typically operates by setting the LD_PRELOAD environment variable to inject the PipeWire JACK compatibility library into the target application's process. This dynamic linking trick allows PipeWire to intercept and handle JACK API calls. This means the application itself doesn't need to be recompiled or specifically aware of PipeWire; it simply "thinks" it's talking to a JACK server.

The behavior of PipeWire's JACK compatibility, including parameters like buffer sizes, sample rates, and latency settings, can be configured through PipeWire's configuration files, often found in /etc/pipewire/jack.conf or user-specific overrides in ~/.config/pipewire/jack.conf. Adjusting these settings can be important for optimizing performance for specific audio tasks and hardware.

The development of PipeWire aimed to create a unified, modern multimedia framework for Linux, addressing limitations of existing systems like PulseAudio and JACK. A core design goal was to ensure broad compatibility with existing audio applications, especially professional audio software heavily reliant on JACK. pw-jack emerged as a crucial component to achieve this. It represents PipeWire's commitment to enabling a smooth transition for users and developers from traditional JACK setups to the new PipeWire ecosystem, integrating professional audio workflows within a versatile, low-latency environment.

pipewire(1), jackd(1), pw-cli(1), pw-play(1), pw-record(1)