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How To unload Pulseaudio loopback audio output devices?

Ubuntu 15

PulseAudio is a powerful sound server for Unix-like operating systems. It offers advanced features such as mixing, network audio, and per-application volume control. One of its features is the ability to create loopback audio output devices, which can be used for various purposes such as streaming audio. However, there may be times when you need to unload these loopback devices. In this article, we will guide you through the process of unloading PulseAudio loopback audio output devices.

Quick Answer

To unload PulseAudio loopback audio output devices, you can use the pactl unload-module command followed by the index number of the module you want to unload. However, finding the correct module index can be tricky. You can use the pactl list short modules command to list all loaded modules and their indices, and then filter the list to find the module index associated with the loopback device you want to unload. Once you have the module index, you can unload the loopback device using the pactl unload-module command.

Understanding PulseAudio Loopback Devices

A loopback device in PulseAudio is a virtual device that can be used to route audio from one application to another. It’s like a virtual cable that connects the output of one application to the input of another. This can be useful in a variety of scenarios, such as streaming audio from one application to another, or recording the output of an application.

Loading PulseAudio Loopback Devices

Before we talk about unloading, let’s understand how to load a loopback device. You can load a loopback device using the pactl load-module command followed by the name of the module you want to load. For example, to load a loopback device, you would use the following command:

pactl load-module module-loopback

This command loads the module-loopback module, which creates a new loopback device.

Unloading PulseAudio Loopback Devices

Once you’re done with a loopback device, you might want to unload it to free up system resources. You can do this using the pactl unload-module command followed by the index number of the module you want to unload.

However, finding the correct module index can be tricky. Fortunately, you can use the pactl list short modules command to list all loaded modules along with their indices. Here’s an example:

pactl list short modules

This command lists all loaded modules in a short format, which includes the module index and the name of the module.

Now, to unload a specific loopback device, you can filter the list of modules to find the ones associated with the loopback device. You can do this using the grep command. For example, if your loopback device has the sink name “mix”, you can find its module index with the following command:

pactl list short modules | grep "sink_name=mix"

This command pipes the output of the pactl list short modules command to the grep command, which filters the output to only include lines that contain the string “sink_name=mix”.

Once you have the module index, you can unload the loopback device with the following command:

pactl unload-module <module-index>

Replace <module-index> with the actual index number of the module you want to unload.

Automating the Process

If you frequently need to load and unload loopback devices, you might want to automate the process. Here’s a script that loads a loopback device, runs a command, and then unloads the loopback device:

# Load the loopback modules
pactl load-module module-null-sink sink_name=mix 
pactl load-module module-loopback sink=mix
pactl load-module module-loopback sink=mix

# Run your command

# Unload the loopback outputs
pactl list short modules | grep "sink_name=mix" | cut -f1 | xargs -L1 pactl unload-module

This script first loads the loopback modules using the pactl load-module command. Then, it runs your command. Finally, it unloads the loopback outputs by using the pactl list short modules command to find the module indices associated with the loopback outputs. The grep command filters the output to only include the modules with the sink name “mix”, and the cut command extracts the module indices. The xargs command then passes each module index to the pactl unload-module command to unload the loopback outputs.

Conclusion

In this article, we’ve covered how to unload PulseAudio loopback audio output devices. We’ve discussed how to load a loopback device, how to list all loaded modules, how to find the module index of a specific loopback device, and how to unload a loopback device. We’ve also provided a script that automates the process of loading and unloading loopback devices. With this knowledge, you should be able to manage your PulseAudio loopback devices effectively.

For more information on PulseAudio and its features, you can visit the official PulseAudio documentation.

How can I create a loopback audio output device in PulseAudio?

To create a loopback audio output device in PulseAudio, you can use the pactl load-module module-loopback command followed by any desired parameters. This will load the module-loopback module and create a new loopback device.

How can I check the list of loaded modules in PulseAudio?

You can use the pactl list short modules command to check the list of loaded modules in PulseAudio. This command will display the module index and the name of each loaded module.

How can I find the module index of a specific loopback device?

You can use the pactl list short modules | grep "sink_name=<device-name>" command, replacing <device-name> with the actual name of your loopback device, to find the module index associated with that device.

How can I unload a loopback audio output device in PulseAudio?

Once you have the module index of the loopback device you want to unload, you can use the pactl unload-module <module-index> command, replacing <module-index> with the actual index number, to unload the loopback device.

Is there a way to automate the loading and unloading of loopback audio output devices?

Yes, you can create a script that loads the loopback modules, runs your desired command, and then unloads the loopback devices. The script can use commands like pactl load-module and pactl unload-module to achieve this automation.

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