PeakSelfHostedPhoton_Voice_Fix

Makes PEAK voice chat work on a self-hosted Photon server.

Companion to PeakSelfHostedPhoton, which redirects the game to your own Photon Server but does not carry voice. Install this alongside it and voice works.

Every player needs it. The patch changes the sending side, so a player without it simply cannot be heard.

Tested on PEAK 2.1.a with Photon Server SDK 4.0.29 (the 2016 build) over GpBinaryV16, four players, host on a public IP.

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What it fixes

Two independent problems. The second only becomes visible once the first is fixed, which is why this looks like a dead end at first.

1. Protocol16 cannot serialize ByteArraySlice

Self-hosting forces the client onto GpBinaryV16, because a 2016-era server speaks nothing newer. Photon Voice hands each Opus frame over as a ByteArraySlice, and Protocol16 has no serializer for that type:

System.Exception: cannot serialize(): ExitGames.Client.Photon.ByteArraySlice
  at ExitGames.Client.Photon.Protocol16.Serialize(...)
  at Photon.Realtime.LoadBalancingPeer.OpRaiseEvent(...)
  at Photon.Voice.LoadBalancingTransport.SendFrame(...)
  at POpusCodec.OpusEncoder.Encode(...)

The encode thread dies on the first frame. The game itself is unaffected, since PEAK's own RPCs use plain types.

The payload is built by Photon.Voice.LoadBalancingTransport2.buildFrameMessage (not PhotonTransportProtocol.buildFrameMessage - the stack trace shows the base class because SendFrame is declared there). A postfix copies the slice into a plain byte[] and releases the slice back to the pool.

Safe on the receiving end: onVoiceFrameEvent already accepts both shapes, and on the wire it is a byte array either way. The slice was only a send-side zero-copy optimisation.

2. Voice frames use a delivery mode old servers drop

With the first fix in, the client reports thousands of successful sends while the server logs nothing at all from the voice peer:

voice: built=4998  raiseOk=5000  raiseFail=0  state=Joined

SendFrame picks the delivery mode like this:

if (flags & 1)                 -> Reliable
else if (cppCompatibilityMode) -> Reliable / Unreliable
else                           -> ReliableUnsequenced / UnreliableUnsequenced

The default path uses the unsequenced modes, which postdate Photon Server 4.0.28 (February 2016). The server drops those commands silently - no error, no log line. Control operations go over the ordinary reliable channel, which is why auth and join succeed while every audio frame vanishes.

A prefix on the LoadBalancingTransport2 constructor forces cppCompatibilityMode = true, the flag that exists for exactly this.

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Verifying

BepInEx/LogOutput.log should contain:

Patched Photon.Voice.LoadBalancingTransport2..ctor
Patched Photon.Voice.LoadBalancingTransport2.buildFrameMessage
Forced cppCompatibilityMode=true: voice frames will use Unreliable ...
Voice frames are now sent as byte[] instead of ByteArraySlice (N bytes in the first frame).

The last line appears on the first word anyone speaks. If it never shows up, the microphone is not producing frames and the problem is elsewhere.

cannot serialize(): ByteArraySlice should be gone from the game's Player.log.

Configuration

BepInEx/config/peak.selfhostedphoton.voicefix.cfg

Setting	Default	What it does
Diagnostics / LogFrameCounters	false	Logs frames built, sends accepted, sends refused and client state every 250 frames. Only for working out why voice is silent - it writes a line every few seconds while anyone is talking.

Compatibility

Both changes are harmless on GpBinaryV18 and on Photon Server 5, so there is no need to remove this after moving to a newer server.

Cost is one array copy per frame (~50 per second) and giving up unsequenced delivery. Next to Opus encoding, that is nothing.

Does nothing on the official Photon Cloud - it only matters when the client has been pushed onto the legacy protocol.

Credits

Diagnosis done by reading the IL of PhotonVoice.API.dll and correlating client counters against Photon Server operation logs. Full write-up, source and a report for the PeakSelfHostedPhoton author are in the source repository.