Merge branch 'main' of ssh://git.polymorph.fr:5070/j.foucher/PS_AI_Agent

- Create OpusEncoder on ALL machines (was Authority-only) — clients now
  encode mic audio, server decodes it; server still encodes agent audio
- FeedExternalAudio / OnMicrophoneDataCaptured: Opus-encode accumulated
  PCM buffer before sending via ServerRelayMicAudio RPC on client path
  (~200 bytes/100ms instead of 3200 bytes = ~16 Kbits/s vs 256 Kbits/s)
- ServerRelayMicAudio_Implementation: auto-detect Opus (size < raw chunk)
  and decode back to PCM before forwarding to WebSocket
- Add public DecompressMicAudio() helper for clean API access from
  InteractionComponent relay without exposing private Opus members
- Graceful fallback: if Opus unavailable, raw PCM is sent/received as before

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

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

@@ -630,8 +630,27 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::FeedExternalAudio(const TArray<float>
 			// Route through relay (clients can't call Server RPCs on NPC actors).
 			if (auto* Relay = FindLocalRelayComponent())
 			{
+				// Opus-compress mic audio before sending over the network.
+				// 3200 bytes raw PCM → ~200 bytes Opus (~16x reduction).
+				if (OpusEncoder.IsValid())
+				{
+					uint32 CompressedSize = static_cast<uint32>(OpusWorkBuffer.Num());
+					OpusEncoder->Encode(MicAccumulationBuffer.GetData(),
+						MicAccumulationBuffer.Num(),
+						OpusWorkBuffer.GetData(), CompressedSize);
+					if (CompressedSize > 0)
+					{
+						TArray<uint8> Compressed;
+						Compressed.Append(OpusWorkBuffer.GetData(), CompressedSize);
+						Relay->ServerRelayMicAudio(GetOwner(), Compressed);
+					}
+				}
+				else
+				{
+					// Fallback: raw PCM (no Opus encoder available).
 					Relay->ServerRelayMicAudio(GetOwner(), MicAccumulationBuffer);
 				}
+			}
 			else
 			{
 				ServerSendMicAudio(MicAccumulationBuffer);
@@ -641,6 +660,33 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::FeedExternalAudio(const TArray<float>
 	}
 }
 
+// ─────────────────────────────────────────────────────────────────────────────
+// Network audio helpers (used by InteractionComponent relay)
+// ─────────────────────────────────────────────────────────────────────────────
+bool UPS_AI_ConvAgent_ElevenLabsComponent::DecompressMicAudio(
+	const TArray<uint8>& CompressedData, TArray<uint8>& OutPCM) const
+{
+	if (!OpusDecoder.IsValid() || CompressedData.Num() >= GetMicChunkMinBytes())
+	{
+		return false; // Not Opus-compressed or no decoder.
+	}
+
+	const uint32 MaxDecoded = 16000 * 2; // 1 sec of 16kHz 16-bit mono
+	OutPCM.SetNumUninitialized(MaxDecoded);
+	uint32 DecodedSize = MaxDecoded;
+	OpusDecoder->Decode(CompressedData.GetData(), CompressedData.Num(),
+		OutPCM.GetData(), DecodedSize);
+
+	if (DecodedSize == 0) return false;
+	OutPCM.SetNum(DecodedSize, EAllowShrinking::No);
+	return true;
+}
+
+int32 UPS_AI_ConvAgent_ElevenLabsComponent::GetMicChunkMinBytesPublic() const
+{
+	return GetMicChunkMinBytes();
+}
+
 // ─────────────────────────────────────────────────────────────────────────────
 // State queries
 // ─────────────────────────────────────────────────────────────────────────────
@@ -1313,10 +1359,27 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::OnMicrophoneDataCaptured(const TArray
 		else
 		{
 			// Route through relay (clients can't call Server RPCs on NPC actors).
+			// Opus-compress before sending — same logic as FeedExternalAudio.
 			if (auto* Relay = FindLocalRelayComponent())
+			{
+				if (OpusEncoder.IsValid())
+				{
+					uint32 CompressedSize = static_cast<uint32>(OpusWorkBuffer.Num());
+					OpusEncoder->Encode(MicAccumulationBuffer.GetData(),
+						MicAccumulationBuffer.Num(),
+						OpusWorkBuffer.GetData(), CompressedSize);
+					if (CompressedSize > 0)
+					{
+						TArray<uint8> Compressed;
+						Compressed.Append(OpusWorkBuffer.GetData(), CompressedSize);
+						Relay->ServerRelayMicAudio(GetOwner(), Compressed);
+					}
+				}
+				else
 				{
 					Relay->ServerRelayMicAudio(GetOwner(), MicAccumulationBuffer);
 				}
+			}
 			else
 			{
 				ServerSendMicAudio(MicAccumulationBuffer);
@@ -1654,14 +1717,16 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::InitOpusCodec()
 	FVoiceModule& VoiceModule = FVoiceModule::Get();
 
 	const ENetRole Role = GetOwnerRole();
-	if (Role == ROLE_Authority)
-	{
+
+	// Encoder: on Authority it encodes agent audio for multicast to clients.
+	// On clients it encodes mic audio for relay to server (~16x compression).
 	OpusEncoder = VoiceModule.CreateVoiceEncoder(
 		PS_AI_ConvAgent_Audio_ElevenLabs::SampleRate,
 		PS_AI_ConvAgent_Audio_ElevenLabs::Channels,
 		EAudioEncodeHint::VoiceEncode_Voice);
-	}
 
+	// Decoder: on clients it decodes agent audio from multicast.
+	// On Authority it decodes mic audio arriving via relay from clients.
 	OpusDecoder = VoiceModule.CreateVoiceDecoder(
 		PS_AI_ConvAgent_Audio_ElevenLabs::SampleRate,
 		PS_AI_ConvAgent_Audio_ElevenLabs::Channels);

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

@@ -603,13 +603,25 @@ void UPS_AI_ConvAgent_InteractionComponent::ServerRelayEndConversation_Implement
 }
 
 void UPS_AI_ConvAgent_InteractionComponent::ServerRelayMicAudio_Implementation(
-	AActor* AgentActor, const TArray<uint8>& PCMBytes)
+	AActor* AgentActor, const TArray<uint8>& AudioBytes)
 {
 	if (!AgentActor) return;
 	auto* Agent = AgentActor->FindComponentByClass<UPS_AI_ConvAgent_ElevenLabsComponent>();
 	if (!Agent) return;
 
-	Agent->ServerSendMicAudio_Implementation(PCMBytes);
+	// Clients Opus-encode mic audio before sending via relay (~200 bytes
+	// instead of 3200 bytes per 100ms chunk). Decode back to raw PCM here
+	// before forwarding to the WebSocket which expects uncompressed int16.
+	TArray<uint8> DecodedPCM;
+	if (Agent->DecompressMicAudio(AudioBytes, DecodedPCM))
+	{
+		Agent->ServerSendMicAudio_Implementation(DecodedPCM);
+	}
+	else
+	{
+		// Raw PCM fallback (no Opus or data is already uncompressed).
+		Agent->ServerSendMicAudio_Implementation(AudioBytes);
+	}
 }
 
 void UPS_AI_ConvAgent_InteractionComponent::ServerRelaySendText_Implementation(

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

@@ -460,6 +460,16 @@ public:
 		FActorComponentTickFunction* ThisTickFunction) override;
 	virtual void GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const override;
 
+	// ── Network audio helpers (used by InteractionComponent relay) ────────
+
+	/** Decompress Opus-encoded mic audio back to raw PCM.
+	 *  Returns true and fills OutPCM on success; returns false if no Opus
+	 *  decoder is available or the data doesn't look compressed. */
+	bool DecompressMicAudio(const TArray<uint8>& CompressedData, TArray<uint8>& OutPCM) const;
+
+	/** Minimum raw PCM bytes expected per mic chunk (used to detect Opus vs raw). */
+	int32 GetMicChunkMinBytesPublic() const;
+
 private:
 	// ── Network OnRep handlers ───────────────────────────────────────────────
 	UFUNCTION()
@@ -602,8 +612,8 @@ private:
 	int32 GetMicChunkMinBytes() const { return MicChunkDurationMs * 32; }
 
 	// ── Opus codec (network audio compression) ───────────────────────────────
-	TSharedPtr<IVoiceEncoder> OpusEncoder;  // Server only
-	TSharedPtr<IVoiceDecoder> OpusDecoder;  // All clients
+	TSharedPtr<IVoiceEncoder> OpusEncoder;  // All: server encodes agent audio, clients encode mic audio
+	TSharedPtr<IVoiceDecoder> OpusDecoder;  // All: clients decode agent audio, server decodes mic audio
 	TArray<uint8> OpusWorkBuffer;           // Reusable scratch buffer for encode/decode
 
 	void InitOpusCodec();