Microphone and audio capture

Reference for microphone device enumeration, selection, and volume on the Convai Player Component, the audio capture component, and Android permissions.

UConvaiPlayerComponent exposes all Blueprint-callable microphone functions under the Convai|Microphone category. Internally it drives a UConvaiAudioCaptureComponent instance that wraps the Unreal AudioCapture engine plugin. On Android, the AndroidPermission plugin handles the runtime microphone permission.

For the complete UConvaiPlayerComponent property set — identity, session, gaze attention, and audio processing — see Convai Player Component.

FCaptureDeviceInfoBP

FCaptureDeviceInfoBP is a BlueprintType struct returned by the device-enumeration and selection functions. All fields are EditAnywhere, BlueprintReadWrite, Category = "Convai|Microphone".

Field	Type	Default	Description
DeviceName	FString	""	Human-readable name shown in device menus.
DeviceIndex	int	0	Zero-based index in the capture device list. Indices can change between sessions when devices are added or removed.
LongDeviceId	FString	""	Platform-specific device identifier. More stable than DeviceIndex across sessions on Windows.
InputChannels	int	0	Number of input channels reported by the device.
PreferredSampleRate	int	0	Device's preferred sample rate in Hz.
bSupportsHardwareAEC	bool	false	true when the device supports hardware acoustic echo cancellation.

Convai|Microphone functions

These BlueprintCallable functions are all on UConvaiPlayerComponent (Blueprint display name Convai Player).

Device enumeration

Function	Parameters	Returns	Description
GetAvailableCaptureDeviceNames	—	TArray<FString>	Names of all available input devices. Use these strings as display labels and as the DeviceName argument to SetCaptureDeviceByName.
GetAvailableCaptureDeviceDetails	—	TArray<FCaptureDeviceInfoBP>	Full FCaptureDeviceInfoBP structs for every available device. Includes index, long ID, channel count, sample rate, and AEC flag.
GetDefaultCaptureDeviceInfo	OutInfo (FCaptureDeviceInfoBP) out	bool	Current source: validates AudioCaptureComponent, then always returns false without populating OutInfo. Do not rely on OutInfo from this node. Use GetAvailableCaptureDeviceDetails or GetActiveCaptureDevice instead.
GetCaptureDeviceInfo	OutInfo (FCaptureDeviceInfoBP) out, DeviceIndex (int)	bool	Populates OutInfo for the device at DeviceIndex. Returns false when the index is out of range.
GetActiveCaptureDevice	OutInfo (FCaptureDeviceInfoBP) out	—	Populates OutInfo with the currently selected capture device.

Device selection

Function	Parameters	Returns	Description
SetCaptureDeviceByIndex	DeviceIndex (int)	bool	Opens the capture device at DeviceIndex. Returns false when the index is out of range or the device cannot be opened.
SetCaptureDeviceByName	DeviceName (FString)	bool	Opens the last device in the enumerated list whose DeviceName matches the input. Returns false when no match is found.

Both selection functions can be called before or during gameplay. After a successful call, GetActiveCaptureDevice reflects the new device.

Volume

Function	Parameters	Returns	Description
SetMicrophoneVolumeMultiplier	InVolumeMultiplier (float)	Success (bool)	Scales the captured audio signal. Success reflects whether a capture component is available, not whether microphone capture is currently streaming or recording.
GetMicrophoneVolumeMultiplier	—	OutVolumeMultiplier (float), Success (bool)	Reads the current volume multiplier. Success reflects capture-component availability.

InVolumeMultiplier has no enforced range in the API. A value of 1.0 applies no gain change. Values above 1.0 amplify the signal; values below 1.0 attenuate it. A value of 0.0 silences the captured audio while keeping the capture session active.

Streaming and recording state

Function	Category	Returns	Description
GetIsStreaming (display name Is Streaming)	`Convai	Microphone`	bool
GetIsRecording (display name Is Recording)	`Convai	Microphone`	bool

StartRecording, FinishRecording, UnmuteStreamingAudio, and MuteStreamingAudio are documented under the Audio streaming and recording section of Convai Player Component.

ConvaiAudioCaptureComponent

UConvaiAudioCaptureComponent (C++ class, ClassGroup = Synth) extends USynthComponent and wraps FConvaiAudioCaptureSynth, which in turn wraps the Unreal FAudioCapture object. UConvaiPlayerComponent creates and owns one instance automatically; you do not need to add UConvaiAudioCaptureComponent to your Actor manually.

In most Blueprints, use the microphone functions on UConvaiPlayerComponent rather than interacting with UConvaiAudioCaptureComponent directly. The player component delegates internally and provides the higher-level streaming API documented in the sections above.

The component declares one Convai-specific Blueprint-configurable property; inherited USynthComponent properties also apply.

Property	Type	Category	Constraints	Description
JitterLatencyFrames	int32	Latency	ClampMin = 0, ClampMax = 1024	Declared latency setting for induced jitter buffering. In current plugin source, this property is not read by the Convai capture implementation, so changing it has no verified runtime effect.

Most device-enumeration and device-switching behavior is driven through UConvaiPlayerComponent — the Blueprint functions listed above delegate to the underlying UConvaiAudioCaptureComponent internally, except GetDefaultCaptureDeviceInfo on the player component, which does not currently forward to the capture component.

At the C++ layer, UConvaiAudioCaptureComponent::GetDefaultCaptureDeviceInfo does populate the system default device. That method is not exposed to Blueprint. The component's other device methods (GetCaptureDevicesAvailable, GetCaptureDeviceInfo, GetActiveCaptureDevice, SetCaptureDevice) are also C++ internal.

Plugin dependencies

Both dependencies are declared in ConvAI.uplugin and are enabled automatically when the Convai plugin is installed. No manual plugin activation is required.

Plugin	Enabled	Purpose
AudioCapture	true	Unreal Engine built-in plugin that provides FAudioCapture and USynthComponent-based capture. Required for all microphone input on Win64 and Android.
AndroidPermission	true	Unreal Engine built-in plugin that provides Blueprint nodes to check and request Android runtime permissions. Required for microphone access on Android.

Android microphone permission

On Android, the OS requires a runtime permission grant for audio capture. Without it, UConvaiAudioCaptureComponent initializes but captures no audio — the Convai character receives no speech input. The plugin does not log a permission-denied message, although stream-open failures can still produce capture warnings.

Request android.permission.RECORD_AUDIO before calling StartSession or UnmuteStreamingAudio. If the permission is denied, audio capture silently produces no data.

Use the AndroidPermission Blueprint nodes to request the permission:

1. Call Check Android Permission with the permission string android.permission.RECORD_AUDIO.
2. If the return value is false, call Request Android Permission for that same string.
3. Bind to the On Permission Request Complete delegate and start the conversation only after the permission is confirmed as granted.

The AndroidPermission plugin nodes are in the Android Permission Blueprint category. They are no-ops on Win64 — the same Blueprint graph works on both platforms without platform guards.

Related reference

The player component page covers the full property surface; the how-to page walks through selecting and testing a device before shipping.

Convai Player ComponentConfigure the microphone