Fix network audio: raw PCM fallback when Opus codecs unavailable

UE5 5.5's FVoiceModule returns NULL encoder/decoder, breaking
Opus-based audio replication. This adds a transparent fallback:
- Server sends raw PCM when OpusEncoder is null (~32KB/s, fine for LAN)
- Client accepts raw PCM when OpusDecoder is null
- Changed MulticastReceiveAgentAudio from Unreliable to Reliable
  to handle larger uncompressed payloads without packet loss
- Added OnlineSubsystemNull config for future Opus compatibility
- Removed premature bAgentSpeaking=true from MulticastAgentStartedSpeaking
  to fix race condition with audio initialization

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Unreal/PS_AI_Agent/Config/DefaultEngine.ini

@@ -153,6 +153,12 @@ FontDPI=72
 +EnumRedirects=(OldName="EPS_AI_Agent_Emotion", NewName="EPS_AI_ConvAgent_Emotion")
 +EnumRedirects=(OldName="EPS_AI_Agent_EmotionIntensity", NewName="EPS_AI_ConvAgent_EmotionIntensity")
 
+[OnlineSubsystem]
+DefaultPlatformService=Null
+
+[OnlineSubsystemNull]
+bEnabled=true
+
 [/Script/AndroidFileServerEditor.AndroidFileServerRuntimeSettings]
 bEnablePlugin=True
 bAllowNetworkConnection=True

Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Private/PS_AI_ConvAgent_ElevenLabsComponent.cpp

@@ -637,46 +637,35 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::HandleAudioReceived(const TArray<uint
 			QueueBefore, (static_cast<float>(QueueBefore) / 16000.0f) * 1000.0f);
 	}
 
-	// Network: Opus-compress and broadcast to all clients before local playback.
+	// Network: broadcast audio to all clients.
-	if (GetOwnerRole() != ROLE_Authority || !OpusEncoder.IsValid())
+	if (GetOwnerRole() == ROLE_Authority)
 	{
-		static bool bWarnedOnce = false;
+		if (OpusEncoder.IsValid())
-		if (!bWarnedOnce)
 		{
-			bWarnedOnce = true;
+			// Opus path: compress then send.
-			UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Warning,
+			uint32 CompressedSize = static_cast<uint32>(OpusWorkBuffer.Num());
-				TEXT("[NET-SRV] Cannot multicast audio! Role=%d (need %d=Authority), OpusEncoder=%s, FVoiceModule=%s"),
+			OpusEncoder->Encode(PCMData.GetData(), PCMData.Num(),
-				static_cast<int32>(GetOwnerRole()), static_cast<int32>(ROLE_Authority),
+				OpusWorkBuffer.GetData(), CompressedSize);
-				OpusEncoder.IsValid() ? TEXT("VALID") : TEXT("NULL"),
-				FVoiceModule::IsAvailable() ? TEXT("available") : TEXT("UNAVAILABLE"));
-		}
-	}
-	if (GetOwnerRole() == ROLE_Authority && OpusEncoder.IsValid())
-	{
-		uint32 CompressedSize = static_cast<uint32>(OpusWorkBuffer.Num());
-		int32 Remainder = OpusEncoder->Encode(PCMData.GetData(), PCMData.Num(),
-			OpusWorkBuffer.GetData(), CompressedSize);
 
-		if (CompressedSize > 0)
+			if (CompressedSize > 0)
-		{
-			TArray<uint8> CompressedData;
-			CompressedData.Append(OpusWorkBuffer.GetData(), CompressedSize);
-
-			if (bDebug)
 			{
-				UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Log,
+				TArray<uint8> CompressedData;
-					TEXT("[NET-SRV] Multicasting Opus audio: %d bytes PCM → %d bytes Opus (%.1f:1 ratio)"),
+				CompressedData.Append(OpusWorkBuffer.GetData(), CompressedSize);
-					PCMData.Num(), CompressedSize,
+				MulticastReceiveAgentAudio(CompressedData);
-					PCMData.Num() > 0 ? static_cast<float>(PCMData.Num()) / CompressedSize : 0.f);
 			}
-
-			MulticastReceiveAgentAudio(CompressedData);
 		}
 		else
 		{
-			UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Warning,
+			// Fallback: send raw PCM (no compression). ~32 KB/s at 16kHz 16-bit mono.
-				TEXT("[NET-SRV] Opus encode produced 0 bytes from %d bytes PCM — audio not sent."),
+			// Fine for LAN; revisit with proper Opus if internet play is needed.
-				PCMData.Num());
+			static bool bWarnedOnce = false;
+			if (!bWarnedOnce)
+			{
+				bWarnedOnce = true;
+				UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Warning,
+					TEXT("[NET-SRV] Opus encoder unavailable — sending raw PCM (no compression)."));
+			}
+			MulticastReceiveAgentAudio(PCMData);
 		}
 	}
 
@@ -1346,57 +1335,36 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::ClientConversationFailed_Implementati
 // Network: Multicast RPCs
 // ─────────────────────────────────────────────────────────────────────────────
 void UPS_AI_ConvAgent_ElevenLabsComponent::MulticastReceiveAgentAudio_Implementation(
-	const TArray<uint8>& OpusData)
+	const TArray<uint8>& AudioData)
 {
 	// Server already handled playback in HandleAudioReceived.
 	if (GetOwnerRole() == ROLE_Authority) return;
 
-	if (!OpusDecoder.IsValid())
-	{
-		UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Warning,
-			TEXT("[NET] MulticastReceiveAgentAudio: OpusDecoder is INVALID — audio dropped. FVoiceModule available: %s"),
-			FVoiceModule::IsAvailable() ? TEXT("YES") : TEXT("NO"));
-		return;
-	}
-
 	// LOD: skip audio if too far (unless this client is the speaker).
 	const float Dist = GetDistanceToLocalPlayer();
 	const bool bIsSpeaker = IsLocalPlayerConversating();
 	if (!bIsSpeaker && AudioLODCullDistance > 0.f && Dist > AudioLODCullDistance)
 	{
-		if (bDebug && DebugVerbosity >= 2)
-		{
-			UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Log,
-				TEXT("[NET] MulticastReceiveAgentAudio: LOD culled (dist=%.0f > cull=%.0f)"),
-				Dist, AudioLODCullDistance);
-		}
 		return;
 	}
 
-	// Decode Opus → PCM.
-	const uint32 MaxDecompressedSize = 16000 * 2; // 1 second of 16kHz 16-bit mono
 	TArray<uint8> PCMBuffer;
-	PCMBuffer.SetNumUninitialized(MaxDecompressedSize);
-	uint32 DecompressedSize = MaxDecompressedSize;
-	OpusDecoder->Decode(OpusData.GetData(), OpusData.Num(),
-		PCMBuffer.GetData(), DecompressedSize);
 
-	if (DecompressedSize == 0)
+	if (OpusDecoder.IsValid())
 	{
-		UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Warning,
+		// Opus path: decode compressed audio.
-			TEXT("[NET] MulticastReceiveAgentAudio: Opus decode failed (0 bytes output from %d bytes input)"),
+		const uint32 MaxDecompressedSize = 16000 * 2;
-			OpusData.Num());
+		PCMBuffer.SetNumUninitialized(MaxDecompressedSize);
-		return;
+		uint32 DecompressedSize = MaxDecompressedSize;
+		OpusDecoder->Decode(AudioData.GetData(), AudioData.Num(),
+			PCMBuffer.GetData(), DecompressedSize);
+		if (DecompressedSize == 0) return;
+		PCMBuffer.SetNum(DecompressedSize);
 	}
-	PCMBuffer.SetNum(DecompressedSize);
+	else
-
-	if (bDebug)
 	{
-		UE_LOG(LogPS_AI_ConvAgent_ElevenLabs, Log,
+		// Fallback: data is already raw PCM (sent uncompressed by server).
-			TEXT("[NET] MulticastReceiveAgentAudio: decoded %d bytes Opus → %d bytes PCM | bAgentSpeaking=%s | AudioComp playing=%s"),
+		PCMBuffer = AudioData;
-			OpusData.Num(), DecompressedSize,
-			bAgentSpeaking ? TEXT("true") : TEXT("false"),
-			(AudioPlaybackComponent && AudioPlaybackComponent->IsPlaying()) ? TEXT("true") : TEXT("false"));
 	}
 
 	// Local playback.

Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Public/PS_AI_ConvAgent_ElevenLabsComponent.h

@@ -339,9 +339,9 @@ public:
 	UFUNCTION(Server, Reliable)
 	void ServerRequestInterrupt();
 
-	/** Broadcast Opus-compressed agent audio to all clients. */
+	/** Broadcast agent audio to all clients (Opus-compressed or raw PCM fallback). */
-	UFUNCTION(NetMulticast, Unreliable)
+	UFUNCTION(NetMulticast, Reliable)
-	void MulticastReceiveAgentAudio(const TArray<uint8>& OpusData);
+	void MulticastReceiveAgentAudio(const TArray<uint8>& AudioData);
 
 	/** Notify all clients that the agent started speaking (first audio chunk). */
 	UFUNCTION(NetMulticast, Reliable)