From e6371f2b564112bec09d9052aff97f1154c4a016 Mon Sep 17 00:00:00 2001
From: nilaoda <nilaoda@live.com>
Date: Mon, 18 Jul 2022 17:42:56 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96VTT=E6=97=B6=E9=97=B4?=
 =?UTF-8?q?=E8=BD=B4=E5=81=8F=E7=A7=BB=E7=9A=84=E8=87=AA=E5=8A=A8=E5=A4=84?=
 =?UTF-8?q?=E7=90=86=E9=80=BB=E8=BE=91?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/N_m3u8DL-RE.Common/Entity/WebVttSub.cs    | 32 ++++++++++++++-----
 .../DownloadManager/SimpleDownloadManager.cs  |  5 +++
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/N_m3u8DL-RE.Common/Entity/WebVttSub.cs b/src/N_m3u8DL-RE.Common/Entity/WebVttSub.cs
index 26a9d31..f2f3100 100644
--- a/src/N_m3u8DL-RE.Common/Entity/WebVttSub.cs
+++ b/src/N_m3u8DL-RE.Common/Entity/WebVttSub.cs
@@ -111,24 +111,40 @@ namespace N_m3u8DL_RE.Common.Entity
             FixTimestamp(webSub, this.MpegtsTimestamp);
             foreach (var item in webSub.Cues)
             {
-                if (!this.Cues.Contains(item)) this.Cues.Add(item);
+                if (!this.Cues.Contains(item))
+                {
+                    //如果相差只有1ms，且payload相同，则拼接
+                    var last = this.Cues.LastOrDefault();
+                    if (last != null && this.Cues.Count > 0 && (item.StartTime - last.EndTime).TotalMilliseconds <= 1 && item.Payload == last.Payload) 
+                    {
+                        last.EndTime = item.EndTime;
+                    }
+                    else
+                    {
+                        this.Cues.Add(item);
+                    }
+                }
             }
             return this;
         }
 
-        public static void FixTimestamp(WebVttSub sub, long baseTimestamp)
+        private void FixTimestamp(WebVttSub sub, long baseTimestamp)
         {
-            if (baseTimestamp == 0 || sub.MpegtsTimestamp == 0)
+            if (sub.MpegtsTimestamp == 0)
             {
                 return;
             }
 
-            //The MPEG2 transport stream clocks (PCR, PTS, DTS) all have units of 1/90000 second
-            var seconds = (sub.MpegtsTimestamp - baseTimestamp) / 90000;
-            for (int i = 0; i < sub.Cues.Count; i++)
+            //确实存在时间轴错误的情况，才修复
+            if ((this.Cues.Count > 0 && sub.Cues.Count > 0 && sub.Cues.First().StartTime < this.Cues.Last().EndTime) || this.Cues.Count == 0)
             {
-                sub.Cues[i].StartTime += TimeSpan.FromSeconds(seconds);
-                sub.Cues[i].EndTime += TimeSpan.FromSeconds(seconds);
+                //The MPEG2 transport stream clocks (PCR, PTS, DTS) all have units of 1/90000 second
+                var seconds = (sub.MpegtsTimestamp - baseTimestamp) / 90000;
+                for (int i = 0; i < sub.Cues.Count; i++)
+                {
+                    sub.Cues[i].StartTime += TimeSpan.FromSeconds(seconds);
+                    sub.Cues[i].EndTime += TimeSpan.FromSeconds(seconds);
+                }
             }
         }
 
diff --git a/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs b/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs
index 85356c5..2d85386 100644
--- a/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs
+++ b/src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs
@@ -132,6 +132,11 @@ namespace N_m3u8DL_RE.DownloadManager
                 {
                     var vttContent = File.ReadAllText(FileDic[seg]!.ActualFilePath);
                     var vtt = WebVttSub.Parse(vttContent);
+                    //手动计算MPEGTS
+                    if (finalVtt.MpegtsTimestamp == 0 && vtt.MpegtsTimestamp == 0)
+                    {
+                        vtt.MpegtsTimestamp = 90 * (long)(seg.Duration * 1000) * seg.Index;
+                    }
                     if (first)
                     {
                         finalVtt = vtt;