Differences between PulseAudio and PipeWire when using pactl

PipeWire version

$ pipewire --version
pipewire
Compiled with libpipewire 0.3.47

pactl version

$ pactl --version
pactl 15.0
Compiled with libpulse 15.0.0
Linked with libpulse 15.0.0

Description of Problem:

When using PipeWire instead of PulseAudio I get a different result with the same pactl command.

How Reproducible:

Always.

Steps to Reproduce:

Execute the following command:

pactl load-module module-pipe-source file=~/virtmic.fifo source_properties=device.description=Virtual-Microphone rate=48000 channels=2

Actual Results:

A source is created, however the description Virtual-Microphone is ignored and the sample format is float32le.

pactl list sources
[...]
Source #66
	State: SUSPENDED
	Name: pactl
	Description: pactl
	Driver: PipeWire
	Sample Specification: float32le 2ch 48000Hz
	Channel Map: front-left,front-right
	Owner Module: 536870913
	Mute: no
	Volume: front-left: 0 /   0% / -inf dB,   front-right: 0 /   0% / -inf dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor of Sink: n/a
	Latency: 0 usec, configured 0 usec
	Flags: DECIBEL_VOLUME LATENCY 
	Properties:
		node.group = "pipewire.dummy"
		node.virtual = "true"
		media.class = "Audio/Source"
		pulse.module.id = "536870913"
		media.name = "pipesource playback"
		stream.is-live = "true"
		node.name = "pactl"
		node.autoconnect = "true"
		adapt.follower.node = ""
		object.register = "false"
		factory.id = "6"
		audio.adapt.follower = ""
		factory.mode = "split"
		library.name = "audioconvert/libspa-audioconvert"
		clock.quantum-limit = "8192"
		client.id = "45"
		object.id = "46"
		object.serial = "66"
	Formats:
		pcm

This is the source created when using PulseAudio by using the same command

Source #1
	State: SUSPENDED
	Name: fifo_input
	Description: Virtual-Microphone
	Driver: module-pipe-source.c
	Sample Specification: s16le 2ch 48000Hz
	Channel Map: front-left,front-right
	Owner Module: 24
	Mute: no
	Volume: front-left: 65536 / 100% / 0.00 dB,   front-right: 65536 / 100% / 0.00 dB
	        balance 0.00
	Base Volume: 65536 / 100% / 0.00 dB
	Monitor of Sink: n/a
	Latency: 0 usec, configured 0 usec
	Flags: DECIBEL_VOLUME LATENCY 
	Properties:
		device.string = "/home/myuser/virtmic.fifo"
		device.description = "Virtual-Microphone"
		device.icon_name = "audio-input-microphone"
	Formats:
		pcm

Expected Results:

The source_properties=device.description=Virtual-Microphone option should not get ignored and if unspecified the sample format should be s16 which is the default format according to the PulseAudio documentation.

Notes:

I managed to set the description with the following command:

pactl load-module module-pipe-source file=~/virtmic.fifo source_name=Virtual-Microphone format=s16 rate=48000 channels=2

Apparently, PipeWire derives the description from source_name and uses it to set both Name and Description fields.