From fc728454d030201c45963ca903fd2fd47a6270d2 Mon Sep 17 00:00:00 2001
From: "j.foucher" <j.foucher@polymorph.fr>
Date: Mon, 2 Mar 2026 15:04:33 +0100
Subject: [PATCH] Fix raw PCM multicast exceeding UE5 replicated array limit

UE5 limits replicated TArrays to 65535 elements. ElevenLabs sends
audio chunks up to ~72K bytes, exceeding this limit when sent as
raw PCM. Split into 32000-byte sub-chunks (1s of 16kHz 16-bit mono)
before calling MulticastReceiveAgentAudio.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../PS_AI_ConvAgent_ElevenLabsComponent.cpp       | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Private/PS_AI_ConvAgent_ElevenLabsComponent.cpp b/Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Private/PS_AI_ConvAgent_ElevenLabsComponent.cpp
index e41a9f0..83d5732 100644
--- a/Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Private/PS_AI_ConvAgent_ElevenLabsComponent.cpp
+++ b/Unreal/PS_AI_Agent/Plugins/PS_AI_ConvAgent/Source/PS_AI_ConvAgent/Private/PS_AI_ConvAgent_ElevenLabsComponent.cpp
@@ -658,14 +658,25 @@ void UPS_AI_ConvAgent_ElevenLabsComponent::HandleAudioReceived(const TArray<uint
 		{
 			// Fallback: send raw PCM (no compression). ~32 KB/s at 16kHz 16-bit mono.
 			// Fine for LAN; revisit with proper Opus if internet play is needed.
+			// UE5 limits replicated TArrays to 65535 elements, so we must chunk.
 			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)."));
+					TEXT("[NET-SRV] Opus encoder unavailable — sending raw PCM in chunks (no compression)."));
+			}
+
+			static constexpr int32 MaxChunkBytes = 32000; // 1s of 16kHz 16-bit mono, well under 65535 limit
+			int32 Offset = 0;
+			while (Offset < PCMData.Num())
+			{
+				const int32 ChunkSize = FMath::Min(MaxChunkBytes, PCMData.Num() - Offset);
+				TArray<uint8> Chunk;
+				Chunk.Append(PCMData.GetData() + Offset, ChunkSize);
+				MulticastReceiveAgentAudio(Chunk);
+				Offset += ChunkSize;
 			}
-			MulticastReceiveAgentAudio(PCMData);
 		}
 	}