maintain stream continuity after playout reset (#868)

* maintain stream continuity after playout reset

* maintain continuity after error streams

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+### Fixed
+- Maintain stream continuity when playout is rebuilt for a channel that is actively being streamed
 
 ## [0.6.2-beta] - 2022-06-18
 ### Fixed

ErsatzTV.Application/Streaming/HlsSessionWorker.cs

@@ -27,8 +27,10 @@ public class HlsSessionWorker : IHlsSessionWorker
     private readonly object _sync = new();
     private string _channelNumber;
     private bool _firstProcess;
+    private bool _hasWrittenSegments;
     private DateTimeOffset _lastAccess;
     private DateTimeOffset _lastDelete = DateTimeOffset.MinValue;
+    private bool _seekNextItem;
     private Option<int> _targetFramerate;
     private Timer _timer;
     private DateTimeOffset _transcodedUntil;
@@ -86,7 +88,11 @@ public class HlsSessionWorker : IHlsSessionWorker
         }
     }
 
-    public void PlayoutUpdated() => _firstProcess = true;
+    public void PlayoutUpdated()
+    {
+        _firstProcess = true;
+        _seekNextItem = true;
+    }
 
     public async Task Run(string channelNumber, TimeSpan idleTimeout, CancellationToken incomingCancellationToken)
     {
@@ -203,7 +209,7 @@ public class HlsSessionWorker : IHlsSessionWorker
 
             IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();
 
-            long ptsOffset = await GetPtsOffset(mediator, _channelNumber, _firstProcess, cancellationToken);
+            long ptsOffset = await GetPtsOffset(mediator, _channelNumber, cancellationToken);
             // _logger.LogInformation("PTS offset: {PtsOffset}", ptsOffset);
 
             var request = new GetPlayoutItemProcessByChannelNumber(
@@ -250,6 +256,13 @@ public class HlsSessionWorker : IHlsSessionWorker
                         _logger.LogInformation("HLS process has completed for channel {Channel}", _channelNumber);
                         _transcodedUntil = processModel.Until;
                         _firstProcess = false;
+                        if (_seekNextItem)
+                        {
+                            _firstProcess = true;
+                            _seekNextItem = false;
+                        }
+
+                        _hasWrittenSegments = true;
                         return true;
                     }
                     else
@@ -294,6 +307,14 @@ public class HlsSessionWorker : IHlsSessionWorker
                             if (commandResult.ExitCode == 0)
                             {
                                 _firstProcess = false;
+                                if (_seekNextItem)
+                                {
+                                    _firstProcess = true;
+                                    _seekNextItem = false;
+                                }
+
+                                _hasWrittenSegments = true;
+
                                 return true;
                             }
                         }
@@ -392,7 +413,6 @@ public class HlsSessionWorker : IHlsSessionWorker
     private async Task<long> GetPtsOffset(
         IMediator mediator,
         string channelNumber,
-        bool firstProcess,
         CancellationToken cancellationToken)
     {
         await Slim.WaitAsync(cancellationToken);
@@ -400,8 +420,8 @@ public class HlsSessionWorker : IHlsSessionWorker
         {
             long result = 0;
 
-            // the first process always starts at zero
-            if (firstProcess)
+            // if we haven't yet written any segments, start at zero
+            if (!_hasWrittenSegments)
             {
                 return result;
             }

ErsatzTV.sln.DotSettings

@@ -61,6 +61,7 @@
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=showtitle/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=strm/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Trakt/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=transcoded/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=tvdb/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=tvshow/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=uniqueid/@EntryIndexedValue">True</s:Boolean>