Network Audio Source

Drop-in networked wrapper for Unity's AudioSource. Add it to any GameObject with an AudioSource to sync audio across the network.

Setup

1. Add an AudioSource component to your GameObject.
2. Add NetworkAudioSource to the same GameObject (it auto-assigns the AudioSource via Reset()).
3. If you plan to change clips at runtime or use PlayOneShot, register those AudioClip assets in your NetworkAssets ScriptableObject.

If the clip is baked into the prefab/scene and never changes at runtime, you do not need to register it in NetworkAssets.

Authority

The _ownerAuth toggle (Inspector) controls who can drive the audio:

• Owner Auth (default): The owning client controls playback. If no owner is set, the server controls it.
• Server Auth: Only the server can control playback.

All public setters and methods guard with IsController(_ownerAuth) and silently no-op on non-controllers.

Public API

Use NetworkAudioSource the same way you would use Unity's AudioSource:

Properties

Property	Type	Description
clip	AudioClip	The clip to play. Must be in NetworkAssets if changed at runtime.
volume	float	Volume (0.0 - 1.0)
pitch	float	Pitch multiplier
loop	bool	Whether to loop
mute	bool	Whether muted
spatialBlend	float	2D (0.0) to 3D (1.0) mix
minDistance	float	Distance where volume stops increasing
maxDistance	float	Distance where attenuation stops
time	float	Playback position in seconds
isPlaying	bool	Read-only, current play state

Methods

Method	Description
Play()	Start playback with the current clip
Play(AudioClip)	Set clip and start playback
Stop()	Stop playback
Pause()	Pause playback
UnPause()	Resume from pause
PlayOneShot(AudioClip, float)	Fire-and-forget SFX (does not affect play state)

How It Works

Dirty Flag System

Each property setter and method sets a bit in a AudioDirtyFlags bitmask. On the next network tick, only the flagged fields are serialized and sent. If nothing changed since the last tick, nothing is sent.

Example: calling only volume = 0.5f sends 2 bytes (flags) + 4 bytes (float) = 6 bytes, not the full ~35 byte state.

Custom Serialization

The AudioSourceDelta struct implements IPacked for hand-written bit-level serialization. It writes the flags bitmask first, then only the fields whose bits are set. Booleans (loop, mute) are packed as single bits.

Channel Selection

The dirty flags are checked each tick to decide reliable vs unreliable delivery:

What changed	Channel	Reason
Play, Stop, Pause, UnPause	Reliable	Discrete state transition; a dropped packet means permanent desync
clip	Reliable	Discrete change; must arrive
volume, pitch, spatialBlend, etc.	Unreliable	Continuous tweaks (fades); next tick resends latest value if dropped
PlayOneShot	Reliable	Fire-and-forget SFX; must not be missed
Late joiner reconcile	Reliable	Full state snapshot; must arrive

If a tick contains both reliable and unreliable changes (e.g. volume = 0.5f + Play() in the same frame), the entire delta is sent reliably.

RPC Routing

Follows the same pattern as NetworkAnimator:

• Server controller -> ObserversRpc(excludeSender: true) directly to clients.
• Client controller -> ServerRpc to server -> server applies locally -> ObserversRpc(excludeSender: true) to other clients.
• Late joiner -> OnObserverAdded sends TargetRpc with full state to the new observer.

Playback Time

• Time is only sent when explicitly changed (via Play(), UnPause(), or the time setter).
• It is not auto-sent every tick while playing, avoiding constant bandwidth for background music.
• On receiving end, if a time value arrives while playing and the local playback has drifted more than 0.1s, it snaps to the received time.

AudioClip Serialization

AudioClips are serialized via PurrNet's Packer<T> for UnityEngine.Object, which looks up the clip's index in NetworkAssets. This sends a small integer index, not the audio data.

• If the clip is not in NetworkAssets, it resolves to null on the remote side.
• If you never change the clip at runtime, it is never serialized (the Clip dirty flag is never set), so it doesn't matter whether it's registered.