From 2e173d4156ca8c9b6a8c1bd2fdfd1d602f42a551 Mon Sep 17 00:00:00 2001
From: feyris-tan <4116042+feyris-tan@users.noreply.github.com>
Date: Sun, 7 Jun 2026 21:56:39 +0200
Subject: [PATCH] Added an option for parsing FLUTE-LCT Frames with ATSC3's
 peculiarities.

---
 skyscraper8/Atsc/A331/Atsc3Unpacker.cs |  3 +++
 skyscraper8/DvbNip/DvbNipReceiver.cs   |  4 ++--
 skyscraper8/Ietf/FLUTE/LctFrame.cs     | 20 ++++++++++++++++++--
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/skyscraper8/Atsc/A331/Atsc3Unpacker.cs b/skyscraper8/Atsc/A331/Atsc3Unpacker.cs
index 51f95f5..d3fb204 100644
--- a/skyscraper8/Atsc/A331/Atsc3Unpacker.cs
+++ b/skyscraper8/Atsc/A331/Atsc3Unpacker.cs
@@ -11,6 +11,7 @@ using skyscraper5.Skyscraper;
 using skyscraper5.Skyscraper.Plugins;
 using skyscraper5.Skyscraper.Scraper;
 using skyscraper8.Atsc.A331.Schema;
+using skyscraper8.Ietf.FLUTE;
 
 namespace skyscraper8.Atsc.A331
 {
@@ -71,6 +72,8 @@ namespace skyscraper8.Atsc.A331
 			{
 				return;
 			}
+
+			LctFrame lctFrame = new LctFrame(udpPacket.Payload, true);
 		}
 
 		private void HandleLls(LlsTable lls)
diff --git a/skyscraper8/DvbNip/DvbNipReceiver.cs b/skyscraper8/DvbNip/DvbNipReceiver.cs
index 7947aad..c331bb2 100644
--- a/skyscraper8/DvbNip/DvbNipReceiver.cs
+++ b/skyscraper8/DvbNip/DvbNipReceiver.cs
@@ -53,7 +53,7 @@ namespace skyscraper8.DvbNip
 					UserDatagram discoveryUdpPacket = new UserDatagram(ipv4Packet);
 					if (discoveryUdpPacket.DestinationPort == 3937)
 					{
-						LctFrame discoveryLctFrame = new LctFrame(discoveryUdpPacket.Payload);
+						LctFrame discoveryLctFrame = new LctFrame(discoveryUdpPacket.Payload, false);
 						if (discoveryLctFrame == null)
 							return;
 						LctHeader lctHeader = discoveryLctFrame.LctHeader;
@@ -77,7 +77,7 @@ namespace skyscraper8.DvbNip
 			}
 			
 			UserDatagram udpPacket = new UserDatagram(ipv4Packet);
-			LctFrame lctFrame = new LctFrame(udpPacket.Payload);
+			LctFrame lctFrame = new LctFrame(udpPacket.Payload, false);
 			if (lctFrame.LctHeader == null)
 			{
 				return;
diff --git a/skyscraper8/Ietf/FLUTE/LctFrame.cs b/skyscraper8/Ietf/FLUTE/LctFrame.cs
index 02fc666..25adab9 100644
--- a/skyscraper8/Ietf/FLUTE/LctFrame.cs
+++ b/skyscraper8/Ietf/FLUTE/LctFrame.cs
@@ -11,8 +11,10 @@ namespace skyscraper8.Ietf.FLUTE
 {
 	internal class LctFrame
 	{
-		public LctFrame(byte[] buffer)
+		public LctFrame(byte[] buffer, bool isAtsc3)
 		{
+			this.Atsc3Compliant = isAtsc3;
+
 			MemoryStream ms = new MemoryStream(buffer, false);
 			byte byteA = ms.ReadUInt8();
 			this.Version = (byteA & 0xf0) >> 4;
@@ -46,7 +48,17 @@ namespace skyscraper8.Ietf.FLUTE
 			if (ms.GetAvailableBytes() < 4)
 				return;
 
-			this.FecHeader = new FecHeader(ms);
+			//TODO: This assumes to always be Code Point 0, like in DVB-NIP, but ATSC3 uses Code Point 8.
+			//ATSC 3 sample: salvage strat1 "Z:\Persönliches\Satellitescommunity\Skyscraper Test Fixture\65.0W_11304.256_V_30000_(2026-05-17 09.44.02)_dump.ts"
+			//DVB-NIP sample: "Z:\Persönliches\Satellitescommunity\Skyscraper Test Fixture\astra1_11141h_gse_nip.ts"
+			if (!isAtsc3)
+			{
+				this.FecHeader = new FecHeader(ms);
+			}
+			else
+			{
+				this.Atsc3ObjectStartOffset = ms.ReadUInt32BE();
+			}
 
 			long avails = ms.GetAvailableBytes();
 			if (avails == 0)
@@ -60,6 +72,10 @@ namespace skyscraper8.Ietf.FLUTE
 			}
 		}
 
+		public uint? Atsc3ObjectStartOffset { get; set; }
+
+		public bool Atsc3Compliant { get; set; }
+
 		public int Version { get; }
 		public int CongestionControlFlag { get; }
 		public int ProtocolSpecificIndication { get; }