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Version: 2.x

Input Device Selection

Unreal does not provide an easy method to switch input devices (like a microphone) when using the default Audio Capture, even though most players would expect this feature in a game with Voice Chat. Let's take a look at how we handle this in the ODIN plugin.

Sample Project​

You can find a sample implementation in the v2.x/input-device-selection branch of the Odin Unreal Minimal Samples Github repository. To view the relevant Blueprints, navigate into Content/Odin/DeviceSelection. Feel free to download the project and set it up in order to view a working implementation of the concepts shown in the following sections.

Creating an Odin Audio Capture​

To change input devices, instead of using Unreal's Create Audio Capture method, we'll use the Create Odin Audio Capture function call. This will create an extended Audio Capture object that allows us to change the audio capture device using either Blueprints or C++.

Your logic for joining an Odin room should look something like this:

The blueprint that we'll create Link to fullscreen image

Please note that we store a reference to the Odin Audio Capture object as a variable. We're going to use it in the next sections to display the available devices in the UI.

info

If you'd like more information on how to setup Odin, please take a look at our Odin Unreal Voice Chat manual.

UI Creation​

You'll probably have to adjust the next steps to fit your UI implementation, but in general it's easy to adapt the necessary UI elements.

We'll create a new Blueprint Widget that gets displayed when the player presses Tab. This Widget should show the available capture devices in a drop-down box and change the active device on selection.

  1. Create a new Widget Blueprint in your project-we'll call it BPW_SelectInputDevice.
  2. In the widget's event graph, create a new Custom Event called UpdateAudioCapture with an input parameter of type Odin Audio Capture. We'll use this event in the next section, so simply leave it unconnected for now.

The Custom Event UpdateAudioCapture in the Widget Blueprint

  1. In your player controller's Begin Play, add a Create Widget call, select the class BP_SelectInputDevice, connect the Self property to the Owning Player input, and save the resulting widget object in a variable.

Initializing the device selection widget in the player controller.

  1. The final step in the player controller is to add logic for toggling the "Select Input Device" UI, as shown below. Please note the call to Update Audio Capture when making the UI visible. This will supply the Audio Capture object to the widget blueprint, which we'll use to request the available capture devices.

Toggle the "Select Input Device" UI based on Input mapping.

tip

If you can't create the InputAction ToggleDeviceSelection event, make sure to add an Action in Project Settings > Input > Action Mappings and bind it to a keyboard input-we're using Tab for testing.

Widget implementation​

Currently, the widget does not contain any visible UI elements, so let's change this. We'll add a simple see-through background and a dropdown box, in which we'll list all available capture devices. Changing the selection in the dropdown box will change the capture device used for Odin. Additionally, we'll preselect the currently active capture device in the dropdown box.

  1. In the widget's Designer mode, add a Canvas Panel as the root element and a Border and ComboBox (String) as direct children. Set the Border element's Brush Color to (0,0,0,0.5) to make it darken the gameplay, but still keep it see-through. Additionally, let's give the ComboBox a meaningful name, e.g. "SelectionDropBox". Let's also add a Button to the root element, for switching the input device selection back to the system default.

The widget's hierarchy and display after adding all elements.

  1. Let's now switch to the Graph mode and start extending our Custom Event UpdateAudioCapture. We'll store the Odin Audio Capture object as a variable, clear the Selection Drop Box and then call Get Capture Devices Available. This will return the available capture devices. We then use the Device Names to fill the drop box.

Request the available capture devices.

  1. We'll implement the Update Selected Option function next. The Get Current Audio Capture Device function of the Audio Capture object returns the currently active Audio Capture device information. We use it to set the selected option on the drop box.

Setting the selection on the drop box to the currently active device

  1. Next, we will listen to the On Selection Changed event of the combo box. Based on the selection, we call Change Capture Device by Name on the UOdinAudioCapture object. After this, the selected Capture Device will be used by Odin to transmit audio data.

Change Capture Device implementation

  1. Finally, we add a listener to the On Clicked event of the Default Input Button. To activate the default device, we simply call Change to Default Capture device on the UOdinAudioCapture object. Because this will internally change the input device to the system default one, we also need to call Update Selected Option again.

Change to default capture device implementation

Now anytime a user chooses a new option, the Odin Audio Capture object will change the capture device and restart the input stream automatically.

What's next?​

This is a very simple implementation with minimal UI, which you'll be able to easily adapt to your project's needs. For more information on Unreal with Odin Voice Chat, check out our Discord and take a look at the following guides we've prepared for you:

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Getting started with ODIN

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Blueprint Reference

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