From e26ca8bf421dae4ed17a92cb54d6f66729d5a24a Mon Sep 17 00:00:00 2001
From: nilaoda <nilaoda@live.com>
Date: Wed, 12 Apr 2023 17:46:21 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E6=AD=A3=E7=9B=B4=E6=92=AD=E5=9C=BA?=
 =?UTF-8?q?=E6=99=AF=E5=A4=9A=E6=B5=81=E5=90=8C=E6=AD=A5=E9=97=AE=E9=A2=98?=
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---
 .../SimpleLiveRecordManager2.cs               | 13 ++---
 src/N_m3u8DL-RE/Util/FilterUtil.cs            | 47 +++++++++++++++++++
 2 files changed, 50 insertions(+), 10 deletions(-)

diff --git a/src/N_m3u8DL-RE/DownloadManager/SimpleLiveRecordManager2.cs b/src/N_m3u8DL-RE/DownloadManager/SimpleLiveRecordManager2.cs
index 73f55fd..da646e8 100644
--- a/src/N_m3u8DL-RE/DownloadManager/SimpleLiveRecordManager2.cs
+++ b/src/N_m3u8DL-RE/DownloadManager/SimpleLiveRecordManager2.cs
@@ -761,15 +761,8 @@ namespace N_m3u8DL_RE.DownloadManager
             var takeLastCount = 15;
             ConcurrentDictionary<int, SpeedContainer> SpeedContainerDic = new(); //速度计算
             ConcurrentDictionary<StreamSpec, bool?> Results = new();
-            //取最后15个分片
-            var maxIndex = SelectedSteams.Min(s => s.Playlist!.MediaParts[0].MediaSegments.Max(s => s.Index));
-            foreach (var item in SelectedSteams)
-            {
-                foreach (var part in item.Playlist!.MediaParts)
-                {
-                    part.MediaSegments = part.MediaSegments.Where(s => s.Index <= maxIndex).TakeLast(takeLastCount).ToList();
-                }
-            }
+            //同步流
+            FilterUtil.SyncStreams(SelectedSteams, takeLastCount);
             //设置等待时间
             if (WAIT_SEC == 0)
             {
@@ -812,7 +805,7 @@ namespace N_m3u8DL_RE.DownloadManager
                     LastFileNameDic[task.Id] = "";
                     DateTimeDic[task.Id] = 0L;
                     RecordingDurDic[task.Id] = 0;
-                    MaxIndexDic[task.Id] = item.Playlist?.MediaParts[0].MediaSegments.Max(s => s.Index) ?? 0L; //最大Index
+                    MaxIndexDic[task.Id] = item.Playlist?.MediaParts[0].MediaSegments.LastOrDefault()?.Index ?? 0L; //最大Index
                     BlockDic[task.Id] = new BufferBlock<List<MediaSegment>>();
                     return (item, task);
                 }).ToDictionary(item => item.item, item => item.task);
diff --git a/src/N_m3u8DL-RE/Util/FilterUtil.cs b/src/N_m3u8DL-RE/Util/FilterUtil.cs
index ae82daf..cec0913 100644
--- a/src/N_m3u8DL-RE/Util/FilterUtil.cs
+++ b/src/N_m3u8DL-RE/Util/FilterUtil.cs
@@ -131,5 +131,52 @@ namespace N_m3u8DL_RE.Util
 
             return selectedStreams;
         }
+
+        /// <summary>
+        /// 直播使用。对齐各个轨道的起始。
+        /// </summary>
+        /// <param name="streams"></param>
+        /// <param name="takeLastCount"></param>
+        public static void SyncStreams(List<StreamSpec> selectedSteams, int takeLastCount = 15)
+        {
+            //通过Date同步
+            if (selectedSteams.All(x => x.Playlist!.MediaParts[0].MediaSegments.All(x => x.DateTime != null)))
+            {
+                var minDate = selectedSteams.Max(s => s.Playlist!.MediaParts[0].MediaSegments.Min(s => s.DateTime))!;
+                foreach (var item in selectedSteams)
+                {
+                    foreach (var part in item.Playlist!.MediaParts)
+                    {
+                        //秒级同步 忽略毫秒
+                        part.MediaSegments = part.MediaSegments.Where(s => s.DateTime!.Value.Ticks / TimeSpan.TicksPerSecond >= minDate.Value.Ticks / TimeSpan.TicksPerSecond).ToList();
+                    }
+                }
+            }
+            else //通过index同步
+            {
+                var minIndex = selectedSteams.Max(s => s.Playlist!.MediaParts[0].MediaSegments.Min(s => s.Index));
+                foreach (var item in selectedSteams)
+                {
+                    foreach (var part in item.Playlist!.MediaParts)
+                    {
+                        part.MediaSegments = part.MediaSegments.Where(s => s.Index >= minIndex).ToList();
+                    }
+                }
+            }
+
+            //取最新的N个分片
+            if (selectedSteams.Any(x => x.Playlist!.MediaParts[0].MediaSegments.Count > takeLastCount))
+            {
+                var skipCount = selectedSteams.Min(x => x.Playlist!.MediaParts[0].MediaSegments.Count) - takeLastCount;
+                if (skipCount < 0) skipCount = 0;
+                foreach (var item in selectedSteams)
+                {
+                    foreach (var part in item.Playlist!.MediaParts)
+                    {
+                        part.MediaSegments = part.MediaSegments.Skip(skipCount).ToList();
+                    }
+                }
+            }
+        }
     }
 }