From f73f41fb8afc6278b66de98cf9f8b5f3f420c1bf Mon Sep 17 00:00:00 2001
From: Genteure <genteure@gmail.com>
Date: Sat, 8 May 2021 18:24:31 +0800
Subject: [PATCH] new toy

---
 .../IProcessingPipelineBuilderExtensions.cs   |  1 +
 .../Pipeline/Rules/PrintSecretMessageRule.cs  | 73 +++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 BililiveRecorder.Flv/Pipeline/Rules/PrintSecretMessageRule.cs

diff --git a/BililiveRecorder.Flv/Pipeline/IProcessingPipelineBuilderExtensions.cs b/BililiveRecorder.Flv/Pipeline/IProcessingPipelineBuilderExtensions.cs
index e96c1ca..5bb796a 100644
--- a/BililiveRecorder.Flv/Pipeline/IProcessingPipelineBuilderExtensions.cs
+++ b/BililiveRecorder.Flv/Pipeline/IProcessingPipelineBuilderExtensions.cs
@@ -24,6 +24,7 @@ namespace BililiveRecorder.Flv.Pipeline
 
         public static IProcessingPipelineBuilder AddDefault(this IProcessingPipelineBuilder builder) =>
             builder
+            .Add<PrintSecretMessageRule>()
             .Add<HandleEndTagRule>()
             .Add<HandleDelayedAudioHeaderRule>()
             .Add<UpdateTimestampOffsetRule>()
diff --git a/BililiveRecorder.Flv/Pipeline/Rules/PrintSecretMessageRule.cs b/BililiveRecorder.Flv/Pipeline/Rules/PrintSecretMessageRule.cs
new file mode 100644
index 0000000..cd2119e
--- /dev/null
+++ b/BililiveRecorder.Flv/Pipeline/Rules/PrintSecretMessageRule.cs
@@ -0,0 +1,73 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+using BililiveRecorder.Flv.Pipeline.Actions;
+using Serilog;
+
+namespace BililiveRecorder.Flv.Pipeline.Rules
+{
+    public class PrintSecretMessageRule : ISimpleProcessingRule
+    {
+        private static readonly ILogger logger = Log.ForContext<PrintSecretMessageRule>();
+
+        public void Run(FlvProcessingContext context, Action next)
+        {
+            for (var i = 0; i < context.Actions.Count; i++)
+            {
+                if (context.Actions[i] is PipelineDataAction dataAction)
+                {
+                    var t = dataAction.Tags.Where(x => x.IsKeyframeData()).FirstOrDefault();
+                    if (t is not null && t.Nalus is not null && t.BinaryData is not null)
+                    {
+                        for (var i1 = 0; i1 < t.Nalus.Count; i1++)
+                        {
+                            var nalu = t.Nalus[i1];
+                            if (nalu.Type == H264NaluType.Sei)
+                            {
+                                ReadMessage(nalu, t.BinaryData);
+                            }
+                        }
+                    }
+                }
+            }
+            next();
+        }
+
+        private static ReadOnlySpan<byte> Identifier => new byte[] {
+            0x3f, 0xb3, 0x4b, (byte)'g', (byte)'e', (byte)'n', (byte)'t',(byte)'e',
+           (byte)'u',(byte)'r',(byte)'e',0x9c,0x67,0xe3,0x7d,0x8c
+        };
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        private static void ReadMessage(H264Nalu nalu, Stream stream)
+        {
+            var size = 0;
+            var id = Identifier;
+
+            stream.Seek(nalu.StartPosition + 1, SeekOrigin.Begin);
+            if (stream.ReadByte() != 5)
+                return;
+
+            while (true)
+            {
+                var read = stream.ReadByte();
+                size += read;
+                if (read != 255)
+                    break;
+            }
+
+            var buffer = new byte[id.Length];
+            stream.Read(buffer, 0, buffer.Length);
+            if (!id.SequenceEqual(buffer))
+                return;
+
+            var data = new byte[size - id.Length];
+            stream.Read(data, 0, data.Length);
+            var str = Encoding.UTF8.GetString(data);
+
+            logger.Information("从直播数据中读到了神秘消息: {Message}", str);
+        }
+    }
+}