Technical overview

The plugin uses Unreal's replicated APlayerState as the identity for each player's voice.

UOnsetVoipWorldSubsystem is created for each game or PIE world. It manages UOnsetVoipTalker instances and automatically creates or destroys one for each APlayerState.

UOnsetVoipTalker handles the voice state for one (remote) player. It receives voice packets, runs them through the playout and jitter-buffer pipeline, updates talking state, and dispatches decoded audio for playback. On clients and listen servers, 2D and 3D audio components are created or reused only when that playback type is needed. It can also create a UOnsetNameplateComponent for remote pawns when nameplate settings allow it.

UOnsetVoipLocalPlayerSubsystem is created for each local player. It manages microphone capture, voice processing, Opus encoding, channel hints, loopback, recording, and sending local voice packets. It is not used on dedicated servers.

UOnsetVoipDataChannel is a custom network channel for FOnsetVoipPacket transmission. A client uses it to send local packets to the server. The server has one channel per connected client and forwards packets only to relevant connections. On a listen server, received remote packets can also be checked for local host playback.

FOnsetVoipPacket contains the compressed Opus voice buffer, sample position, amplitude, optional owner APlayerState, optional voice channel hints, and network serialization.

UOnsetVoipAudioComponent owns a UOnsetVoipSoundWave, binds to decoded talker audio, and applies the configured attenuation and source effect chain assets.

UOnsetVoipSoundWave is based on USoundWave and uses Unreal's ISoundGenerator path. It buffers decoded float PCM and supplies it directly to Unreal's audio mixer for playback.