update changelog for release v0.1.1-alpha [no ci]

* add music video album to search index

* update search docs

CHANGELOG.md

@@ -5,6 +5,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 
+## [0.1.1-alpha] - 2021-10-10
+### Added
+- Add music video album to search index
+  - This requires rebuilding the search index and search results may be empty or incomplete until the rebuild is complete
+
+### Changed
+- Remove forced initial delay from `HLS Segmenter` streaming mode
+- Upgrade nvidia docker image from 18.04 to 20.04
+
 ## [0.1.0-alpha] - 2021-10-08
 ### Added
 - Add *experimental* streaming mode `HLS Segmenter` (most similar to `HLS Hybrid`) 
@@ -660,7 +669,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Initial release to facilitate testing outside of Docker.
 
 
-[Unreleased]: https://github.com/jasongdove/ErsatzTV/compare/v0.1.0-alpha...HEAD
+[Unreleased]: https://github.com/jasongdove/ErsatzTV/compare/v0.1.1-alpha...HEAD
+[0.1.1-alpha]: https://github.com/jasongdove/ErsatzTV/compare/v0.1.0-alpha...v0.1.1-alpha
 [0.1.0-alpha]: https://github.com/jasongdove/ErsatzTV/compare/v0.0.62-alpha...v0.1.0-alpha
 [0.0.62-alpha]: https://github.com/jasongdove/ErsatzTV/compare/v0.0.61-alpha...v0.0.62-alpha
 [0.0.61-alpha]: https://github.com/jasongdove/ErsatzTV/compare/v0.0.60-alpha...v0.0.61-alpha

ErsatzTV.Application/ErsatzTV.Application.csproj

@@ -7,10 +7,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="AsyncFixer" Version="1.5.1">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
       <PackageReference Include="MediatR" Version="9.0.0" />
       <PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="5.0.0" />
       <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="17.0.63">

ErsatzTV.Application/MediaCards/Mapper.cs

@@ -1,5 +1,4 @@
-using System;
-using System.Linq;
+using System.Linq;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Emby;
@@ -101,6 +100,7 @@ namespace ErsatzTV.Application.MediaCards
                 musicVideoMetadata.MusicVideo.Artist.ArtistMetadata.Head().Title,
                 musicVideoMetadata.SortTitle,
                 musicVideoMetadata.Plot,
+                musicVideoMetadata.Album,
                 GetThumbnail(musicVideoMetadata, None, None));
 
         internal static ArtistCardViewModel ProjectToViewModel(ArtistMetadata artistMetadata) =>

ErsatzTV.Application/MediaCards/MusicVideoCardViewModel.cs

@@ -7,6 +7,7 @@
         string Subtitle,
         string SortTitle,
         string Plot,
+        string Album,
         string Poster) : MediaCardViewModel(
         MusicVideoId,
         Title,

ErsatzTV.Application/Streaming/Commands/CleanUpFFmpegSessions.cs

@@ -1,9 +0,0 @@
-using ErsatzTV.Core;
-using LanguageExt;
-using MediatR;
-using Unit = LanguageExt.Unit;
-
-namespace ErsatzTV.Application.Streaming.Commands
-{
-    public record CleanUpFFmpegSessions : IRequest<Either<BaseError, Unit>>, IFFmpegWorkerRequest;
-}

ErsatzTV.Application/Streaming/Commands/CleanUpFFmpegSessionsHandler.cs

@@ -1,27 +0,0 @@
-using System.Threading;
-using System.Threading.Channels;
-using System.Threading.Tasks;
-using ErsatzTV.Core;
-using LanguageExt;
-using MediatR;
-using Unit = LanguageExt.Unit;
-
-namespace ErsatzTV.Application.Streaming.Commands
-{
-    public class CleanUpFFmpegSessionsHandler : IRequestHandler<CleanUpFFmpegSessions, Either<BaseError, Unit>>
-    {
-        private readonly ChannelWriter<IFFmpegWorkerRequest> _channel;
-
-        public CleanUpFFmpegSessionsHandler(ChannelWriter<IFFmpegWorkerRequest> channel)
-        {
-            _channel = channel;
-        }
-
-        public async Task<Either<BaseError, Unit>>
-            Handle(CleanUpFFmpegSessions request, CancellationToken cancellationToken)
-        {
-            await _channel.WriteAsync(request, cancellationToken);
-            return Unit.Default;
-        }
-    }
-}

ErsatzTV.Application/Streaming/Commands/StartFFmpegSessionHandler.cs

@@ -1,13 +1,13 @@
 using System;
 using System.IO;
 using System.Threading;
-using System.Threading.Channels;
 using System.Threading.Tasks;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Errors;
 using ErsatzTV.Core.Interfaces.FFmpeg;
 using ErsatzTV.Core.Interfaces.Metadata;
 using LanguageExt;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using static LanguageExt.Prelude;
 
@@ -15,21 +15,21 @@ namespace ErsatzTV.Application.Streaming.Commands
 {
     public class StartFFmpegSessionHandler : MediatR.IRequestHandler<StartFFmpegSession, Either<BaseError, Unit>>
     {
-        private readonly ChannelWriter<IFFmpegWorkerRequest> _channel;
         private readonly ILogger<StartFFmpegSessionHandler> _logger;
+        private readonly IServiceScopeFactory _serviceScopeFactory;
         private readonly IFFmpegSegmenterService _ffmpegSegmenterService;
         private readonly ILocalFileSystem _localFileSystem;
 
         public StartFFmpegSessionHandler(
-            IFFmpegSegmenterService ffmpegSegmenterService,
             ILocalFileSystem localFileSystem,
-            ChannelWriter<IFFmpegWorkerRequest> channel,
-            ILogger<StartFFmpegSessionHandler> logger)
+            ILogger<StartFFmpegSessionHandler> logger,
+            IServiceScopeFactory serviceScopeFactory,
+            IFFmpegSegmenterService ffmpegSegmenterService)
         {
-            _ffmpegSegmenterService = ffmpegSegmenterService;
             _localFileSystem = localFileSystem;
-            _channel = channel;
             _logger = logger;
+            _serviceScopeFactory = serviceScopeFactory;
+            _ffmpegSegmenterService = ffmpegSegmenterService;
         }
 
         public Task<Either<BaseError, Unit>> Handle(StartFFmpegSession request, CancellationToken cancellationToken) =>
@@ -42,24 +42,51 @@ namespace ErsatzTV.Application.Streaming.Commands
 
         private async Task<Unit> StartProcess(StartFFmpegSession request)
         {
-            await _channel.WriteAsync(request);
+            using IServiceScope scope = _serviceScopeFactory.CreateScope();
+            HlsSessionWorker worker = scope.ServiceProvider.GetRequiredService<HlsSessionWorker>();
+            _ffmpegSegmenterService.SessionWorkers.AddOrUpdate(request.ChannelNumber, _ => worker, (_, _) => worker);
 
-            // TODO: find some other way to let ffmpeg get ahead
-            await Task.Delay(TimeSpan.FromSeconds(5));
+            // fire and forget worker
+            _ = worker.Run(request.ChannelNumber)
+                .ContinueWith(
+                    _ => _ffmpegSegmenterService.SessionWorkers.TryRemove(
+                        request.ChannelNumber,
+                        out IHlsSessionWorker _),
+                    TaskScheduler.Default);
+
+            string playlistFileName = Path.Combine(
+                FileSystemLayout.TranscodeFolder,
+                request.ChannelNumber,
+                "live.m3u8");
+
+            while (!File.Exists(playlistFileName))
+            {
+                await Task.Delay(TimeSpan.FromMilliseconds(100));
+            }
 
             return Unit.Default;
         }
 
         private Task<Validation<BaseError, Unit>> Validate(StartFFmpegSession request) =>
-            ProcessMustNotExist(request)
+            SessionMustBeInactive(request)
                 .BindT(_ => FolderMustBeEmpty(request));
 
-        private Task<Validation<BaseError, Unit>> ProcessMustNotExist(StartFFmpegSession request) =>
-            Optional(_ffmpegSegmenterService.ProcessExistsForChannel(request.ChannelNumber))
-                .Filter(exists => exists == false)
+        private Task<Validation<BaseError, Unit>> SessionMustBeInactive(StartFFmpegSession request)
+        {
+            var result = Optional(_ffmpegSegmenterService.SessionWorkers.TryAdd(request.ChannelNumber, null))
+                .Filter(success => success)
                 .Map(_ => Unit.Default)
-                .ToValidation<BaseError>(new ChannelHasProcess())
-                .AsTask();
+                .ToValidation<BaseError>(new ChannelSessionAlreadyActive());
+
+            if (result.IsFail && _ffmpegSegmenterService.SessionWorkers.TryGetValue(
+                request.ChannelNumber,
+                out IHlsSessionWorker worker))
+            {
+                worker?.Touch();
+            }
+
+            return result.AsTask();
+        }
 
         private Task<Validation<BaseError, Unit>> FolderMustBeEmpty(StartFFmpegSession request)
         {

ErsatzTV.Application/Streaming/HlsSessionWorker.cs

@@ -0,0 +1,207 @@
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Timers;
+using ErsatzTV.Application.Streaming.Queries;
+using ErsatzTV.Core;
+using ErsatzTV.Core.FFmpeg;
+using ErsatzTV.Core.Interfaces.FFmpeg;
+using LanguageExt;
+using MediatR;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Timer = System.Timers.Timer;
+
+namespace ErsatzTV.Application.Streaming
+{
+    public class HlsSessionWorker : IHlsSessionWorker
+    {
+        private readonly IServiceScopeFactory _serviceScopeFactory;
+        private readonly ILogger<HlsSessionWorker> _logger;
+        private DateTimeOffset _lastAccess;
+        private DateTimeOffset _transcodedUntil;
+        private readonly Timer _timer = new(TimeSpan.FromMinutes(2).TotalMilliseconds) { AutoReset = false };
+        private readonly object _sync = new();
+        private DateTimeOffset _playlistStart;
+
+        public HlsSessionWorker(IServiceScopeFactory serviceScopeFactory, ILogger<HlsSessionWorker> logger)
+        {
+            _serviceScopeFactory = serviceScopeFactory;
+            _logger = logger;
+        }
+
+        public DateTimeOffset PlaylistStart => _playlistStart;
+
+        public void Touch()
+        {
+            lock (_sync)
+            {
+                _lastAccess = DateTimeOffset.Now;
+
+                _timer.Stop();
+                _timer.Start();
+            }
+        }
+
+        public async Task Run(string channelNumber)
+        {
+            var cts = new CancellationTokenSource();
+            void Cancel(object o, ElapsedEventArgs e) => cts.Cancel();
+
+            try
+            {
+                _timer.Elapsed += Cancel;
+
+                CancellationToken cancellationToken = cts.Token;
+
+                _logger.LogInformation("Starting HLS session for channel {Channel}", channelNumber);
+
+                Touch();
+                _transcodedUntil = DateTimeOffset.Now;
+                _playlistStart = _transcodedUntil;
+
+                // start initial transcode WITHOUT realtime throttle
+                if (!await Transcode(channelNumber, true, false, cancellationToken))
+                {
+                    return;
+                }
+
+                while (!cancellationToken.IsCancellationRequested)
+                {
+                    // TODO: configurable? 5 minutes?
+                    if (DateTimeOffset.Now - _lastAccess > TimeSpan.FromMinutes(2))
+                    {
+                        _logger.LogInformation("Stopping idle HLS session for channel {Channel}", channelNumber);
+                        return;
+                    }
+
+                    var transcodedBuffer = TimeSpan.FromSeconds(
+                        Math.Max(0, _transcodedUntil.Subtract(DateTimeOffset.Now).TotalSeconds));
+                    if (transcodedBuffer <= TimeSpan.FromMinutes(1))
+                    {
+                        // only use realtime encoding when we're at least 30 seconds ahead
+                        bool realtime = transcodedBuffer >= TimeSpan.FromSeconds(30);
+                        if (!await Transcode(channelNumber, false, realtime, cancellationToken))
+                        {
+                            return;
+                        }
+                    }
+                    else
+                    {
+                        await TrimAndDelete(channelNumber, cancellationToken);
+                        await Task.Delay(TimeSpan.FromSeconds(5), cancellationToken);
+                    }
+                }
+            }
+            finally
+            {
+                _timer.Elapsed -= Cancel;
+            }
+        }
+
+        private async Task<bool> Transcode(string channelNumber, bool firstProcess, bool realtime, CancellationToken cancellationToken)
+        {
+            try
+            {
+                using IServiceScope scope = _serviceScopeFactory.CreateScope();
+                IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();
+
+                var request = new GetPlayoutItemProcessByChannelNumber(
+                    channelNumber,
+                    "segmenter",
+                    firstProcess ? DateTimeOffset.Now : _transcodedUntil.AddSeconds(1),
+                    !firstProcess,
+                    realtime);
+
+                // _logger.LogInformation("Request {@Request}", request);
+
+                Either<BaseError, PlayoutItemProcessModel> result = await mediator.Send(request, cancellationToken);
+
+                // _logger.LogInformation("Result {Result}", result.ToString());
+
+                foreach (BaseError error in result.LeftAsEnumerable())
+                {
+                    _logger.LogWarning(
+                        "Failed to create process for HLS session on channel {Channel}: {Error}",
+                        channelNumber,
+                        error.ToString());
+
+                    return false;
+                }
+
+                foreach (PlayoutItemProcessModel processModel in result.RightAsEnumerable())
+                {
+                    await TrimAndDelete(channelNumber, cancellationToken);
+                    
+                    Process process = processModel.Process;
+
+                    _logger.LogDebug(
+                        "ffmpeg hls arguments {FFmpegArguments}",
+                        string.Join(" ", process.StartInfo.ArgumentList));
+
+                    process.Start();
+                    try
+                    {
+                        await process.WaitForExitAsync(cancellationToken);
+                        process.WaitForExit();
+                    }
+                    catch (TaskCanceledException)
+                    {
+                        _logger.LogInformation("Terminating HLS process for channel {Channel}", channelNumber);
+                        process.Kill();
+                        process.WaitForExit();
+
+                        return false;
+                    }
+
+                    _logger.LogInformation("HLS process has completed for channel {Channel}", channelNumber);
+
+                    _transcodedUntil = processModel.Until;
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error transcoding channel {Channel}", channelNumber);
+                return false;
+            }
+
+            return true;
+        }
+        
+        private async Task TrimAndDelete(string channelNumber, CancellationToken cancellationToken)
+        {
+            string playlistFileName = Path.Combine(
+                FileSystemLayout.TranscodeFolder,
+                channelNumber,
+                "live.m3u8");
+
+            if (File.Exists(playlistFileName))
+            {
+                // trim playlist and insert discontinuity before appending with new ffmpeg process
+                string[] lines = await File.ReadAllLinesAsync(playlistFileName, cancellationToken);
+                TrimPlaylistResult trimResult = HlsPlaylistFilter.TrimPlaylistWithDiscontinuity(
+                    _playlistStart,
+                    DateTimeOffset.Now.AddMinutes(-1),
+                    lines);
+                await File.WriteAllTextAsync(playlistFileName, trimResult.Playlist, cancellationToken);
+
+                // delete old segments
+                foreach (string file in Directory.GetFiles(
+                    Path.Combine(FileSystemLayout.TranscodeFolder, channelNumber),
+                    "*.ts"))
+                {
+                    string fileName = Path.GetFileName(file);
+                    if (fileName.StartsWith("live") && int.Parse(fileName.Replace("live", string.Empty).Split('.')[0]) <
+                        trimResult.Sequence)
+                    {
+                        File.Delete(file);
+                    }
+                }
+
+                _playlistStart = trimResult.PlaylistStart;
+            }
+        }
+    }
+}

ErsatzTV.Application/Streaming/PlayoutItemProcessModel.cs

@@ -0,0 +1,7 @@
+using System;
+using System.Diagnostics;
+
+namespace ErsatzTV.Application.Streaming
+{
+    public record PlayoutItemProcessModel(Process Process, DateTimeOffset Until);
+}

ErsatzTV.Application/Streaming/Queries/FFmpegProcessHandler.cs

@@ -1,5 +1,4 @@
 using System;
-using System.Diagnostics;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -14,7 +13,7 @@ using static LanguageExt.Prelude;
 
 namespace ErsatzTV.Application.Streaming.Queries
 {
-    public abstract class FFmpegProcessHandler<T> : IRequestHandler<T, Either<BaseError, Process>>
+    public abstract class FFmpegProcessHandler<T> : IRequestHandler<T, Either<BaseError, PlayoutItemProcessModel>>
         where T : FFmpegProcessRequest
     {
         private readonly IDbContextFactory<TvContext> _dbContextFactory;
@@ -22,16 +21,16 @@ namespace ErsatzTV.Application.Streaming.Queries
         protected FFmpegProcessHandler(IDbContextFactory<TvContext> dbContextFactory) =>
             _dbContextFactory = dbContextFactory;
 
-        public async Task<Either<BaseError, Process>> Handle(T request, CancellationToken cancellationToken)
+        public async Task<Either<BaseError, PlayoutItemProcessModel>> Handle(T request, CancellationToken cancellationToken)
         {
             await using TvContext dbContext = _dbContextFactory.CreateDbContext();
             Validation<BaseError, Tuple<Channel, string>> validation = await Validate(dbContext, request);
             return await validation.Match(
                 tuple => GetProcess(dbContext, request, tuple.Item1, tuple.Item2),
-                error => Task.FromResult<Either<BaseError, Process>>(error.Join()));
+                error => Task.FromResult<Either<BaseError, PlayoutItemProcessModel>>(error.Join()));
         }
 
-        protected abstract Task<Either<BaseError, Process>> GetProcess(
+        protected abstract Task<Either<BaseError, PlayoutItemProcessModel>> GetProcess(
             TvContext dbContext,
             T request,
             Channel channel,

ErsatzTV.Application/Streaming/Queries/FFmpegProcessRequest.cs

@@ -1,4 +1,4 @@
-using System.Diagnostics;
+using System;
 using ErsatzTV.Core;
 using LanguageExt;
 using MediatR;
@@ -6,5 +6,10 @@ using MediatR;
 namespace ErsatzTV.Application.Streaming.Queries
 {
     public record FFmpegProcessRequest
-        (string ChannelNumber, string Mode, bool StartAtZero) : IRequest<Either<BaseError, Process>>;
+    (
+        string ChannelNumber,
+        string Mode,
+        DateTimeOffset Now,
+        bool StartAtZero,
+        bool HlsRealtime) : IRequest<Either<BaseError, PlayoutItemProcessModel>>;
 }

ErsatzTV.Application/Streaming/Queries/GetConcatProcessByChannelNumber.cs

@@ -1,11 +1,15 @@
-namespace ErsatzTV.Application.Streaming.Queries
+using System;
+
+namespace ErsatzTV.Application.Streaming.Queries
 {
     public record GetConcatProcessByChannelNumber : FFmpegProcessRequest
     {
         public GetConcatProcessByChannelNumber(string scheme, string host, string channelNumber) : base(
             channelNumber,
             "ts",
-            false)
+            DateTimeOffset.Now,
+            false,
+            true)
         {
             Scheme = scheme;
             Host = host;

ErsatzTV.Application/Streaming/Queries/GetConcatProcessByChannelNumberHandler.cs

@@ -1,4 +1,5 @@
-using System.Diagnostics;
+using System;
+using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using ErsatzTV.Core;
@@ -27,7 +28,7 @@ namespace ErsatzTV.Application.Streaming.Queries
             _runtimeInfo = runtimeInfo;
         }
 
-        protected override async Task<Either<BaseError, Process>> GetProcess(
+        protected override async Task<Either<BaseError, PlayoutItemProcessModel>> GetProcess(
             TvContext dbContext,
             GetConcatProcessByChannelNumber request,
             Channel channel,
@@ -37,12 +38,14 @@ namespace ErsatzTV.Application.Streaming.Queries
                 .GetValue<bool>(ConfigElementKey.FFmpegSaveReports)
                 .Map(result => result.IfNone(false));
 
-            return _ffmpegProcessService.ConcatChannel(
+            Process process = _ffmpegProcessService.ConcatChannel(
                 ffmpegPath,
                 saveReports,
                 channel,
                 request.Scheme,
                 request.Host);
+
+            return new PlayoutItemProcessModel(process, DateTimeOffset.MaxValue);
         }
     }
 }

ErsatzTV.Application/Streaming/Queries/GetPlayoutItemProcessByChannelNumber.cs

@@ -1,11 +1,20 @@
-namespace ErsatzTV.Application.Streaming.Queries
+using System;
+
+namespace ErsatzTV.Application.Streaming.Queries
 {
     public record GetPlayoutItemProcessByChannelNumber : FFmpegProcessRequest
     {
-        public GetPlayoutItemProcessByChannelNumber(string channelNumber, string mode, bool startAtZero) : base(
+        public GetPlayoutItemProcessByChannelNumber(
+            string channelNumber,
+            string mode,
+            DateTimeOffset now,
+            bool startAtZero,
+            bool hlsRealtime) : base(
             channelNumber,
             mode,
-            startAtZero)
+            now,
+            startAtZero,
+            hlsRealtime)
         {
         }
     }

ErsatzTV.Application/Streaming/Queries/GetPlayoutItemProcessByChannelNumberHandler.cs

@@ -48,13 +48,14 @@ namespace ErsatzTV.Application.Streaming.Queries
             _runtimeInfo = runtimeInfo;
         }
 
-        protected override async Task<Either<BaseError, Process>> GetProcess(
+        protected override async Task<Either<BaseError, PlayoutItemProcessModel>> GetProcess(
             TvContext dbContext,
             GetPlayoutItemProcessByChannelNumber request,
             Channel channel,
             string ffmpegPath)
         {
-            DateTimeOffset now = DateTimeOffset.Now;
+            DateTimeOffset now = request.Now;
+            
             Either<BaseError, PlayoutItemWithPath> maybePlayoutItem = await dbContext.PlayoutItems
                 .Include(i => i.MediaItem)
                 .ThenInclude(mi => (mi as Episode).MediaVersions)
@@ -103,17 +104,22 @@ namespace ErsatzTV.Application.Streaming.Queries
                         .GetValue<int>(ConfigElementKey.FFmpegVaapiDriver)
                         .MapT(i => (VaapiDriver)i);
 
-                    return Right<BaseError, Process>(
-                        await _ffmpegProcessService.ForPlayoutItem(
-                            ffmpegPath,
-                            saveReports,
-                            channel,
-                            version,
-                            playoutItemWithPath.Path,
-                            playoutItemWithPath.PlayoutItem.StartOffset,
-                            request.StartAtZero ? playoutItemWithPath.PlayoutItem.StartOffset : now,
-                            maybeGlobalWatermark,
-                            maybeVaapiDriver));
+                    Process process = await _ffmpegProcessService.ForPlayoutItem(
+                        ffmpegPath,
+                        saveReports,
+                        channel,
+                        version,
+                        playoutItemWithPath.Path,
+                        playoutItemWithPath.PlayoutItem.StartOffset,
+                        request.StartAtZero ? playoutItemWithPath.PlayoutItem.StartOffset : now,
+                        maybeGlobalWatermark,
+                        maybeVaapiDriver,
+                        request.StartAtZero,
+                        request.HlsRealtime);
+
+                    var result = new PlayoutItemProcessModel(process, playoutItemWithPath.PlayoutItem.FinishOffset);
+
+                    return Right<BaseError, PlayoutItemProcessModel>(result);
                 },
                 async error =>
                 {
@@ -132,16 +138,21 @@ namespace ErsatzTV.Application.Streaming.Queries
                                 .MapT(pi => pi.StartOffset - now),
                             () => Option<TimeSpan>.None.AsTask());
 
+                    DateTimeOffset finish = maybeDuration.Match(d => now.Add(d), () => now);
+
                     switch (error)
                     {
                         case UnableToLocatePlayoutItem:
                             if (channel.FFmpegProfile.Transcode)
                             {
-                                return _ffmpegProcessService.ForError(
+                                Process errorProcess = _ffmpegProcessService.ForError(
                                     ffmpegPath,
                                     channel,
                                     maybeDuration,
                                     "Channel is Offline");
+
+
+                                return new PlayoutItemProcessModel(errorProcess, finish);
                             }
                             else
                             {
@@ -153,7 +164,13 @@ namespace ErsatzTV.Application.Streaming.Queries
                         case PlayoutItemDoesNotExistOnDisk:
                             if (channel.FFmpegProfile.Transcode)
                             {
-                                return _ffmpegProcessService.ForError(ffmpegPath, channel, maybeDuration, error.Value);
+                                Process errorProcess = _ffmpegProcessService.ForError(
+                                    ffmpegPath,
+                                    channel,
+                                    maybeDuration,
+                                    error.Value);
+
+                                return new PlayoutItemProcessModel(errorProcess, finish);
                             }
                             else
                             {
@@ -165,11 +182,13 @@ namespace ErsatzTV.Application.Streaming.Queries
                         default:
                             if (channel.FFmpegProfile.Transcode)
                             {
-                                return _ffmpegProcessService.ForError(
+                                Process errorProcess = _ffmpegProcessService.ForError(
                                     ffmpegPath,
                                     channel,
                                     maybeDuration,
                                     "Channel is Offline");
+
+                                return new PlayoutItemProcessModel(errorProcess, finish);
                             }
                             else
                             {

ErsatzTV.Core.Tests/ErsatzTV.Core.Tests.csproj

@@ -6,10 +6,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="AsyncFixer" Version="1.5.1">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
       <PackageReference Include="FluentAssertions" Version="6.1.0" />
       <PackageReference Include="LanguageExt.Core" Version="3.4.15" />
       <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="5.0.2" />

ErsatzTV.Core.Tests/FFmpeg/HlsPlaylistFilterTests.cs

@@ -0,0 +1,223 @@
+using System;
+using ErsatzTV.Core.FFmpeg;
+using FluentAssertions;
+using NUnit.Framework;
+
+namespace ErsatzTV.Core.Tests.FFmpeg
+{
+    [TestFixture]
+    public class HlsPlaylistFilterTests
+    {
+        [Test]
+        public void HlsPlaylistFilter_ShouldRewriteProgramDateTime()
+        {
+            var start = new DateTimeOffset(2021, 10, 9, 8, 0, 0, TimeSpan.FromHours(-5));
+            string[] input = @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:49.320-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:53.320-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:57.320-0500
+live001139.ts".Split(Environment.NewLine);
+
+            TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(start, start.AddSeconds(-30), input);
+
+            result.PlaylistStart.Should().Be(start);
+            result.Sequence.Should().Be(1137);
+            result.Playlist.Should().Be(
+                @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-DISCONTINUITY-SEQUENCE:0
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:00.000-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:04.000-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:08.000-0500
+live001139.ts
+");
+        }
+        
+        [Test]
+        public void HlsPlaylistFilter_ShouldLimitSegments()
+        {
+            var start = new DateTimeOffset(2021, 10, 9, 8, 0, 0, TimeSpan.FromHours(-5));
+            string[] input = @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:49.320-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:53.320-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:57.320-0500
+live001139.ts".Split(Environment.NewLine);
+
+            TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(start, start.AddSeconds(-30), input, 2);
+
+            result.PlaylistStart.Should().Be(start);
+            result.Sequence.Should().Be(1137);
+            result.Playlist.Should().Be(
+                @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-DISCONTINUITY-SEQUENCE:0
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:00.000-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:04.000-0500
+live001138.ts
+");
+        }
+        
+        [Test]
+        public void HlsPlaylistFilter_ShouldAddDiscontinuity()
+        {
+            var start = new DateTimeOffset(2021, 10, 9, 8, 0, 0, TimeSpan.FromHours(-5));
+            string[] input = @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:49.320-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:53.320-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:57.320-0500
+live001139.ts".Split(Environment.NewLine);
+
+            TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(
+                start,
+                start.AddSeconds(-30),
+                input,
+                int.MaxValue,
+                true);
+
+            result.PlaylistStart.Should().Be(start);
+            result.Sequence.Should().Be(1137);
+            result.Playlist.Should().Be(
+                @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-DISCONTINUITY-SEQUENCE:0
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:00.000-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:04.000-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:08.000-0500
+live001139.ts
+#EXT-X-DISCONTINUITY
+");
+        }
+
+        [Test]
+        public void HlsPlaylistFilter_ShouldFilterOldSegments()
+        {
+            var start = new DateTimeOffset(2021, 10, 9, 8, 0, 0, TimeSpan.FromHours(-5));
+            string[] input = @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:49.320-0500
+live001137.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:53.320-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:57.320-0500
+live001139.ts".Split(Environment.NewLine);
+
+            TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(start, start.AddSeconds(6), input);
+
+            result.PlaylistStart.Should().Be(start.AddSeconds(8));
+            result.Sequence.Should().Be(1139);
+            result.Playlist.Should().Be(
+                @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1139
+#EXT-X-DISCONTINUITY-SEQUENCE:0
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:08.000-0500
+live001139.ts
+");
+        }
+        
+        [Test]
+        public void HlsPlaylistFilter_ShouldFilterOldDiscontinuity()
+        {
+            var start = new DateTimeOffset(2021, 10, 9, 8, 0, 0, TimeSpan.FromHours(-5));
+            string[] input = @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1137
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:49.320-0500
+live001137.ts
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:53.320-0500
+live001138.ts
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-08T08:34:57.320-0500
+live001139.ts".Split(Environment.NewLine);
+
+            TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(start, start.AddSeconds(6), input);
+
+            result.PlaylistStart.Should().Be(start.AddSeconds(8));
+            result.Sequence.Should().Be(1139);
+            result.Playlist.Should().Be(
+                @"#EXTM3U
+#EXT-X-VERSION:6
+#EXT-X-TARGETDURATION:4
+#EXT-X-MEDIA-SEQUENCE:1139
+#EXT-X-DISCONTINUITY-SEQUENCE:1
+#EXT-X-INDEPENDENT-SEGMENTS
+#EXT-X-DISCONTINUITY
+#EXTINF:4.000000,
+#EXT-X-PROGRAM-DATE-TIME:2021-10-09T08:00:08.000-0500
+live001139.ts
+");
+        }
+    }
+}

ErsatzTV.Core.Tests/FFmpeg/TranscodingTests.cs

@@ -184,7 +184,9 @@ namespace ErsatzTV.Core.Tests.FFmpeg
                 now,
                 now,
                 None,
-                None);
+                None,
+                false,
+                false);
 
             process.StartInfo.RedirectStandardError = true;
 

ErsatzTV.Core/Errors/ChannelHasProcess.cs

@@ -1,9 +0,0 @@
-namespace ErsatzTV.Core.Errors
-{
-    public class ChannelHasProcess : BaseError
-    {
-        public ChannelHasProcess() : base("Channel already has ffmpeg process")
-        {
-        }
-    }
-}

ErsatzTV.Core/Errors/ChannelSessionAlreadyActive.cs

@@ -0,0 +1,9 @@
+namespace ErsatzTV.Core.Errors
+{
+    public class ChannelSessionAlreadyActive : BaseError
+    {
+        public ChannelSessionAlreadyActive() : base("Channel already has HLS session")
+        {
+        }
+    }
+}

ErsatzTV.Core/ErsatzTV.Core.csproj

@@ -7,10 +7,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="AsyncFixer" Version="1.5.1">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
       <PackageReference Include="Flurl" Version="3.0.2" />
       <PackageReference Include="LanguageExt.Core" Version="3.4.15" />
       <PackageReference Include="MediatR" Version="9.0.0" />

ErsatzTV.Core/FFmpeg/FFmpegProcessBuilder.cs

@@ -109,7 +109,14 @@ namespace ErsatzTV.Core.FFmpeg
         {
             if (realtimeOutput)
             {
-                _arguments.Add("-re");
+                if (!_arguments.Contains("-re"))
+                {
+                    _arguments.Add("-re");
+                }
+            }
+            else
+            {
+                _arguments.RemoveAll(s => s == "-re");
             }
 
             return this;
@@ -310,8 +317,10 @@ namespace ErsatzTV.Core.FFmpeg
             return this;
         }
 
-        public FFmpegProcessBuilder WithHls(string channelNumber, MediaVersion mediaVersion)
+        public FFmpegProcessBuilder WithHls(string channelNumber, MediaVersion mediaVersion, bool startAtZero)
         {
+            const int SEGMENT_SECONDS = 4;
+            
             if (!int.TryParse(mediaVersion.RFrameRate, out int frameRate))
             {
                 string[] split = (mediaVersion.RFrameRate ?? string.Empty).Split("/");
@@ -329,15 +338,17 @@ namespace ErsatzTV.Core.FFmpeg
             _arguments.AddRange(
                 new[]
                 {
-                    "-g", $"{frameRate * 2}",
-                    "-keyint_min", $"{frameRate * 2}",
-                    // "-force_key_frames",
-                    // "expr:gte(t,n_forced*2)",
+                    "-use_wallclock_as_timestamps", "1",
+                    "-g", $"{frameRate * SEGMENT_SECONDS}",
+                    "-keyint_min", $"{frameRate * SEGMENT_SECONDS}",
+                    "-force_key_frames", $"expr:gte(t,n_forced*{SEGMENT_SECONDS})",
                     "-f", "hls",
-                    "-hls_time", "2",
-                    "-hls_list_size", "10",
+                    "-hls_time", $"{SEGMENT_SECONDS}",
+                    "-hls_list_size", "0",
                     "-segment_list_flags", "+live",
-                    "-hls_flags", "delete_segments+program_date_time+append_list+discont_start+omit_endlist",
+                    "-hls_segment_filename",
+                    Path.Combine(FileSystemLayout.TranscodeFolder, channelNumber, "live%06d.ts"),
+                    "-hls_flags", "program_date_time+append_list+omit_endlist+independent_segments",
                     Path.Combine(FileSystemLayout.TranscodeFolder, channelNumber, "live.m3u8")
                 });
 

ErsatzTV.Core/FFmpeg/FFmpegProcessService.cs

@@ -39,7 +39,9 @@ namespace ErsatzTV.Core.FFmpeg
             DateTimeOffset start,
             DateTimeOffset now,
             Option<ChannelWatermark> globalWatermark,
-            Option<VaapiDriver> maybeVaapiDriver)
+            Option<VaapiDriver> maybeVaapiDriver,
+            bool startAtZero,
+            bool hlsRealtime)
         {
             MediaStream videoStream = await _ffmpegStreamSelector.SelectVideoStream(channel, version);
             Option<MediaStream> maybeAudioStream = await _ffmpegStreamSelector.SelectAudioStream(channel, version);
@@ -118,7 +120,8 @@ namespace ErsatzTV.Core.FFmpeg
             {
                 // HLS needs to segment and generate playlist
                 case StreamingMode.HttpLiveStreamingSegmenter:
-                    return builder.WithHls(channel.Number, version)
+                    return builder.WithHls(channel.Number, version, startAtZero)
+                        .WithRealtimeOutput(hlsRealtime)
                         .Build();
                 default:
                     return builder.WithFormat("mpegts")

ErsatzTV.Core/FFmpeg/FFmpegSegmenterService.cs

@@ -1,96 +1,23 @@
-using System;
-using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
-using System.Threading;
+using System.Collections.Concurrent;
 using ErsatzTV.Core.Interfaces.FFmpeg;
-using LanguageExt;
-using Microsoft.Extensions.Logging;
 
 namespace ErsatzTV.Core.FFmpeg
 {
     public class FFmpegSegmenterService : IFFmpegSegmenterService
     {
-        private static readonly ConcurrentDictionary<string, ProcessAndToken> Processes = new();
-
-        private readonly ILogger<FFmpegSegmenterService> _logger;
-
-        public FFmpegSegmenterService(ILogger<FFmpegSegmenterService> logger) => _logger = logger;
-
-        public bool ProcessExistsForChannel(string channelNumber)
+        public FFmpegSegmenterService()
         {
-            if (Processes.TryGetValue(channelNumber, out ProcessAndToken processAndToken))
-            {
-                if (!processAndToken.Process.HasExited || !Processes.TryRemove(
-                    new KeyValuePair<string, ProcessAndToken>(channelNumber, processAndToken)))
-                {
-                    return true;
-                }
-            }
-
-            return false;
+            SessionWorkers = new ConcurrentDictionary<string, IHlsSessionWorker>();
         }
 
-        public bool TryAdd(string channelNumber, Process process)
-        {
-            var cts = new CancellationTokenSource();
-            var processAndToken = new ProcessAndToken(process, cts, DateTimeOffset.Now);
-            if (Processes.TryAdd(channelNumber, processAndToken))
-            {
-                CancellationToken token = cts.Token;
-                token.Register(process.Kill);
-                return true;
-            }
-
-            return false;
-        }
+        public ConcurrentDictionary<string, IHlsSessionWorker> SessionWorkers { get; }
 
         public void TouchChannel(string channelNumber)
         {
-            if (Processes.TryGetValue(channelNumber, out ProcessAndToken processAndToken))
+            if (SessionWorkers.TryGetValue(channelNumber, out IHlsSessionWorker worker))
             {
-                ProcessAndToken newValue = processAndToken with { LastAccess = DateTimeOffset.Now };
-                if (!Processes.TryUpdate(channelNumber, newValue, processAndToken))
-                {
-                    _logger.LogWarning("Failed to update last access for channel {Channel}", channelNumber);
-                }
+                worker?.Touch();
             }
         }
-
-        public void CleanUpSessions()
-        {
-            foreach ((string key, (_, CancellationTokenSource cts, DateTimeOffset lastAccess)) in Processes.ToList())
-            {
-                // TODO: configure this time span? 5 min?
-                if (DateTimeOffset.Now.Subtract(lastAccess) > TimeSpan.FromMinutes(2))
-                {
-                    _logger.LogDebug("Cleaning up ffmpeg session for channel {Channel}", key);
-
-                    cts.Cancel();
-                    Processes.TryRemove(key, out _);
-                }
-            }
-        }
-
-        public Unit KillAll()
-        {
-            foreach ((string key, ProcessAndToken processAndToken) in Processes.ToList())
-            {
-                try
-                {
-                    processAndToken.TokenSource.Cancel();
-                    Processes.TryRemove(key, out _);
-                }
-                catch (Exception ex)
-                {
-                    _logger.LogInformation(ex, "Error killing process");
-                }
-            }
-
-            return Unit.Default;
-        }
-
-        private record ProcessAndToken(Process Process, CancellationTokenSource TokenSource, DateTimeOffset LastAccess);
     }
 }

ErsatzTV.Core/FFmpeg/HlsPlaylistFilter.cs

@@ -0,0 +1,111 @@
+using System;
+using System.Text;
+
+namespace ErsatzTV.Core.FFmpeg
+{
+    public class HlsPlaylistFilter
+    {
+        public static TrimPlaylistResult TrimPlaylist(
+            DateTimeOffset playlistStart,
+            DateTimeOffset filterBefore,
+            string[] lines,
+            int maxSegments = 10,
+            bool endWithDiscontinuity = false)
+        {
+            DateTimeOffset currentTime = playlistStart;
+            DateTimeOffset nextPlaylistStart = DateTimeOffset.MaxValue;
+            
+            var discontinuitySequence = 0;
+            var startSequence = 0;
+            var output = new StringBuilder();
+            var started = false;
+            var i = 0;
+            var segments = 0;
+            while (!lines[i].StartsWith("#EXTINF:"))
+            {
+                if (lines[i].StartsWith("#EXT-X-DISCONTINUITY-SEQUENCE"))
+                {
+                    discontinuitySequence = int.Parse(lines[i].Split(':')[1]);
+                }
+
+                i++;
+            }
+
+            while (i < lines.Length)
+            {
+                if (segments >= maxSegments)
+                {
+                    break;
+                }
+
+                string line = lines[i];
+                // _logger.LogInformation("Line: {Line}", line);
+                if (line.StartsWith("#EXT-X-DISCONTINUITY"))
+                {
+                    if (started)
+                    {
+                        output.AppendLine("#EXT-X-DISCONTINUITY");
+                    }
+                    else
+                    {
+                        discontinuitySequence++;
+                    }
+
+                    i++;
+                    continue;
+                }
+
+                var duration = TimeSpan.FromSeconds(double.Parse(lines[i].TrimEnd(',').Split(':')[1]));
+                if (currentTime < filterBefore)
+                {
+                    currentTime += duration;
+                    i += 3;
+                    continue;
+                }
+    
+                nextPlaylistStart = currentTime < nextPlaylistStart ? currentTime : nextPlaylistStart;
+
+                if (!started)
+                {
+                    startSequence = int.Parse(lines[i + 2].Replace("live", string.Empty).Split('.')[0]);
+
+                    output.AppendLine("#EXTM3U");
+                    output.AppendLine("#EXT-X-VERSION:6");
+                    output.AppendLine("#EXT-X-TARGETDURATION:4");
+                    output.AppendLine($"#EXT-X-MEDIA-SEQUENCE:{startSequence}");
+                    output.AppendLine($"#EXT-X-DISCONTINUITY-SEQUENCE:{discontinuitySequence}");
+                    output.AppendLine("#EXT-X-INDEPENDENT-SEGMENTS");
+                    output.AppendLine("#EXT-X-DISCONTINUITY");
+
+                    started = true;
+                }
+
+                output.AppendLine(lines[i]);
+                string offset = currentTime.ToString("zzz").Replace(":", string.Empty);
+                output.AppendLine($"#EXT-X-PROGRAM-DATE-TIME:{currentTime:yyyy-MM-ddTHH:mm:ss.fff}{offset}");
+                output.AppendLine(lines[i + 2]);
+
+                currentTime += duration;
+                segments++;
+                i += 3;
+            }
+
+            if (endWithDiscontinuity)
+            {
+                output.AppendLine("#EXT-X-DISCONTINUITY");
+            }
+
+            return new TrimPlaylistResult(nextPlaylistStart, startSequence, output.ToString());
+        }
+
+        public static TrimPlaylistResult TrimPlaylistWithDiscontinuity(
+            DateTimeOffset playlistStart,
+            DateTimeOffset filterBefore,
+            string[] lines)
+        {
+            return TrimPlaylist(playlistStart, filterBefore, lines, int.MaxValue, true);
+        }
+    }
+
+    public record TrimPlaylistResult(DateTimeOffset PlaylistStart, int Sequence, string Playlist);
+}

ErsatzTV.Core/Interfaces/FFmpeg/IFFmpegSegmenterService.cs

@@ -1,14 +1,11 @@
-using System.Diagnostics;
-using LanguageExt;
+using System.Collections.Concurrent;
 
 namespace ErsatzTV.Core.Interfaces.FFmpeg
 {
     public interface IFFmpegSegmenterService
     {
-        bool ProcessExistsForChannel(string channelNumber);
-        bool TryAdd(string channelNumber, Process process);
+        ConcurrentDictionary<string, IHlsSessionWorker> SessionWorkers { get; }
+
         void TouchChannel(string channelNumber);
-        void CleanUpSessions();
-        Unit KillAll();
     }
 }

ErsatzTV.Core/Interfaces/FFmpeg/IHlsSessionWorker.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace ErsatzTV.Core.Interfaces.FFmpeg
+{
+    public interface IHlsSessionWorker
+    {
+        DateTimeOffset PlaylistStart { get; }
+        void Touch();
+    }
+}

ErsatzTV.Infrastructure/ErsatzTV.Infrastructure.csproj

@@ -8,10 +8,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="AsyncFixer" Version="1.5.1">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
       <PackageReference Include="Dapper" Version="2.0.90" />
       <PackageReference Include="Lucene.Net" Version="4.8.0-beta00014" />
       <PackageReference Include="Lucene.Net.Analysis.Common" Version="4.8.0-beta00014" />

ErsatzTV.Infrastructure/Search/SearchIndex.cs

@@ -52,6 +52,7 @@ namespace ErsatzTV.Infrastructure.Search
         private const string DirectorField = "director";
         private const string WriterField = "writer";
         private const string TraktListField = "trakt_list";
+        private const string AlbumField = "album";
 
         public const string MovieType = "movie";
         public const string ShowType = "show";
@@ -74,7 +75,7 @@ namespace ErsatzTV.Infrastructure.Search
             _initialized = false;
         }
 
-        public int Version => 16;
+        public int Version => 17;
 
         public Task<bool> Initialize(ILocalFileSystem localFileSystem)
         {
@@ -624,6 +625,11 @@ namespace ErsatzTV.Infrastructure.Search
                                 Field.Store.NO));
                     }
 
+                    if (!string.IsNullOrWhiteSpace(metadata.Album))
+                    {
+                        doc.Add(new TextField(AlbumField, metadata.Album, Field.Store.NO));
+                    }
+
                     if (!string.IsNullOrWhiteSpace(metadata.Plot))
                     {
                         doc.Add(new TextField(PlotField, metadata.Plot ?? string.Empty, Field.Store.NO));

ErsatzTV/Controllers/InternalController.cs

@@ -1,4 +1,6 @@
-using System.Threading.Tasks;
+using System;
+using System.Diagnostics;
+using System.Threading.Tasks;
 using ErsatzTV.Application.Streaming.Queries;
 using ErsatzTV.Extensions;
 using LanguageExt;
@@ -31,25 +33,29 @@ namespace ErsatzTV.Controllers
             string channelNumber,
             [FromQuery]
             string mode = "mixed") =>
-            _mediator.Send(new GetPlayoutItemProcessByChannelNumber(channelNumber, mode, false)).Map(
-                result =>
-                    result.Match<IActionResult>(
-                        process =>
-                        {
-                            _logger.LogDebug(
-                                "ffmpeg arguments {FFmpegArguments}",
-                                string.Join(" ", process.StartInfo.ArgumentList));
-                            process.Start();
-                            return new FileStreamResult(process.StandardOutput.BaseStream, "video/mp2t");
-                        },
-                        error =>
-                        {
-                            _logger.LogError(
-                                "Failed to create stream for channel {ChannelNumber}: {Error}",
-                                channelNumber,
-                                error.Value);
-                            return BadRequest(error.Value);
-                        }
-                    ));
+            _mediator.Send(
+                    new GetPlayoutItemProcessByChannelNumber(channelNumber, mode, DateTimeOffset.Now, false, true))
+                .Map(
+                    result =>
+                        result.Match<IActionResult>(
+                            processModel =>
+                            {
+                                Process process = processModel.Process;
+
+                                _logger.LogDebug(
+                                    "ffmpeg arguments {FFmpegArguments}",
+                                    string.Join(" ", process.StartInfo.ArgumentList));
+                                process.Start();
+                                return new FileStreamResult(process.StandardOutput.BaseStream, "video/mp2t");
+                            },
+                            error =>
+                            {
+                                _logger.LogError(
+                                    "Failed to create stream for channel {ChannelNumber}: {Error}",
+                                    channelNumber,
+                                    error.Value);
+                                return BadRequest(error.Value);
+                            }
+                        ));
     }
 }

ErsatzTV/Controllers/IptvController.cs

@@ -1,6 +1,7 @@
-using System.Threading.Channels;
+using System;
+using System.Diagnostics;
+using System.IO;
 using System.Threading.Tasks;
-using ErsatzTV.Application;
 using ErsatzTV.Application.Channels.Queries;
 using ErsatzTV.Application.Images;
 using ErsatzTV.Application.Images.Queries;
@@ -9,6 +10,8 @@ using ErsatzTV.Application.Streaming.Queries;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Domain;
 using ErsatzTV.Core.Errors;
+using ErsatzTV.Core.FFmpeg;
+using ErsatzTV.Core.Interfaces.FFmpeg;
 using ErsatzTV.Core.Iptv;
 using LanguageExt;
 using MediatR;
@@ -22,18 +25,18 @@ namespace ErsatzTV.Controllers
     [ApiExplorerSettings(IgnoreApi = true)]
     public class IptvController : ControllerBase
     {
-        private readonly ChannelWriter<IFFmpegWorkerRequest> _channel;
+        private readonly IFFmpegSegmenterService _ffmpegSegmenterService;
         private readonly ILogger<IptvController> _logger;
         private readonly IMediator _mediator;
 
         public IptvController(
             IMediator mediator,
             ILogger<IptvController> logger,
-            ChannelWriter<IFFmpegWorkerRequest> channel)
+            IFFmpegSegmenterService ffmpegSegmenterService)
         {
             _mediator = mediator;
             _logger = logger;
-            _channel = channel;
+            _ffmpegSegmenterService = ffmpegSegmenterService;
         }
 
         [HttpGet("iptv/channels.m3u")]
@@ -53,8 +56,10 @@ namespace ErsatzTV.Controllers
             _mediator.Send(new GetConcatProcessByChannelNumber(Request.Scheme, Request.Host.ToString(), channelNumber))
                 .Map(
                     result => result.Match<IActionResult>(
-                        process =>
+                        processModel =>
                         {
+                            Process process = processModel.Process;
+                            
                             _logger.LogInformation("Starting ts stream for channel {ChannelNumber}", channelNumber);
                             // _logger.LogDebug(
                             //     "ffmpeg concat arguments {FFmpegArguments}",
@@ -64,6 +69,26 @@ namespace ErsatzTV.Controllers
                         },
                         error => BadRequest(error.Value)));
 
+        [HttpGet("iptv/session/{channelNumber}/hls.m3u8")]
+        public async Task<IActionResult> GetLivePlaylist(string channelNumber)
+        {
+            if (_ffmpegSegmenterService.SessionWorkers.TryGetValue(channelNumber, out IHlsSessionWorker worker))
+            {
+                DateTimeOffset now = DateTimeOffset.Now.AddSeconds(-30);
+            
+                string fileName = Path.Combine(FileSystemLayout.TranscodeFolder, channelNumber, "live.m3u8");
+                if (System.IO.File.Exists(fileName))
+                {
+                    string[] input = await System.IO.File.ReadAllLinesAsync(fileName);
+
+                    TrimPlaylistResult result = HlsPlaylistFilter.TrimPlaylist(worker.PlaylistStart, now, input);
+                    return Content(result.Playlist, "application/vnd.apple.mpegurl");
+                }
+            }
+
+            return NotFound();
+        }
+
         [HttpGet("iptv/channel/{channelNumber}.m3u8")]
         public async Task<IActionResult> GetHttpLiveStreamingVideo(
             string channelNumber,
@@ -75,13 +100,13 @@ namespace ErsatzTV.Controllers
                 case "segmenter":
                     Either<BaseError, Unit> result = await _mediator.Send(new StartFFmpegSession(channelNumber, false));
                     return result.Match<IActionResult>(
-                        _ => Redirect($"/iptv/session/{channelNumber}/live.m3u8"),
+                        _ => Redirect($"/iptv/session/{channelNumber}/hls.m3u8"),
                         error =>
                         {
                             switch (error)
                             {
-                                case ChannelHasProcess:
-                                    return RedirectPreserveMethod($"/iptv/session/{channelNumber}/live.m3u8");
+                                case ChannelSessionAlreadyActive:
+                                    return RedirectPreserveMethod($"/iptv/session/{channelNumber}/hls.m3u8");
                                 default:
                                     _logger.LogWarning(
                                         "Failed to start segmenter for channel {ChannelNumber}: {Error}",

ErsatzTV/ErsatzTV.csproj

@@ -13,10 +13,6 @@
     </ItemGroup>
 
     <ItemGroup>
-      <PackageReference Include="AsyncFixer" Version="1.5.1">
-        <PrivateAssets>all</PrivateAssets>
-        <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      </PackageReference>
       <PackageReference Include="Blazored.LocalStorage" Version="4.1.5" />
       <PackageReference Include="FluentValidation" Version="10.3.3" />
       <PackageReference Include="FluentValidation.AspNetCore" Version="10.3.3" />

ErsatzTV/Pages/Artist.razor

@@ -139,6 +139,13 @@
                 <MudCardContent Class="ml-3">
                     <div style="display: flex; flex-direction: column; height: 100%">
                         <MudText Typo="Typo.h4">@musicVideo.Title</MudText>
+                        @if (!string.IsNullOrWhiteSpace(musicVideo.Album))
+                        {
+                            <div style="display: flex; flex-direction: row">
+                                <MudText GutterBottom="true">Album:&nbsp;</MudText>
+                                <MudLink Href="@(@$"album:""{musicVideo.Album}""".GetRelativeSearchQuery())">@musicVideo.Album</MudLink>
+                            </div>
+                        }
                         <MudText Style="flex-grow: 1">@musicVideo.Plot</MudText>
                         <div class="mt-6">
                             <MudButton Variant="Variant.Filled"

ErsatzTV/Services/FFmpegSchedulerService.cs

@@ -1,34 +0,0 @@
-using System;
-using System.Threading;
-using System.Threading.Channels;
-using System.Threading.Tasks;
-using ErsatzTV.Application;
-using ErsatzTV.Application.Streaming.Commands;
-using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
-
-namespace ErsatzTV.Services
-{
-    public class FFmpegSchedulerService : BackgroundService
-    {
-        private readonly ILogger<FFmpegSchedulerService> _logger;
-        private readonly ChannelWriter<IFFmpegWorkerRequest> _workerChannel;
-
-        public FFmpegSchedulerService(
-            ChannelWriter<IFFmpegWorkerRequest> workerChannel,
-            ILogger<FFmpegSchedulerService> logger)
-        {
-            _workerChannel = workerChannel;
-            _logger = logger;
-        }
-
-        protected override async Task ExecuteAsync(CancellationToken cancellationToken)
-        {
-            while (!cancellationToken.IsCancellationRequested)
-            {
-                await _workerChannel.WriteAsync(new CleanUpFFmpegSessions(), cancellationToken);
-                await Task.Delay(TimeSpan.FromMinutes(1), cancellationToken);
-            }
-        }
-    }
-}

ErsatzTV/Services/FFmpegWorkerService.cs

@@ -1,16 +1,11 @@
 using System;
-using System.Diagnostics;
 using System.IO;
 using System.Threading;
 using System.Threading.Channels;
 using System.Threading.Tasks;
 using ErsatzTV.Application;
 using ErsatzTV.Application.Streaming.Commands;
-using ErsatzTV.Application.Streaming.Queries;
-using ErsatzTV.Core;
 using ErsatzTV.Core.Interfaces.FFmpeg;
-using LanguageExt;
-using MediatR;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -21,20 +16,17 @@ namespace ErsatzTV.Services
     public class FFmpegWorkerService : BackgroundService
     {
         private readonly ChannelReader<IFFmpegWorkerRequest> _channel;
-        private readonly ChannelWriter<IFFmpegWorkerRequest> _channelWriter;
         private readonly ILogger<FFmpegWorkerService> _logger;
         private readonly IFFmpegSegmenterService _ffmpegSegmenterService;
         private readonly IServiceScopeFactory _serviceScopeFactory;
 
         public FFmpegWorkerService(
             ChannelReader<IFFmpegWorkerRequest> channel,
-            ChannelWriter<IFFmpegWorkerRequest> channelWriter,
             IServiceScopeFactory serviceScopeFactory,
             ILogger<FFmpegWorkerService> logger,
             IFFmpegSegmenterService ffmpegSegmenterService)
         {
             _channel = channel;
-            _channelWriter = channelWriter;
             _serviceScopeFactory = serviceScopeFactory;
             _logger = logger;
             _ffmpegSegmenterService = ffmpegSegmenterService;
@@ -49,7 +41,7 @@ namespace ErsatzTV.Services
                 try
                 {
                     using IServiceScope scope = _serviceScopeFactory.CreateScope();
-                    IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();
+                    // IMediator mediator = scope.ServiceProvider.GetRequiredService<IMediator>();
 
                     switch (request)
                     {
@@ -58,52 +50,6 @@ namespace ErsatzTV.Services
                             {
                                 _ffmpegSegmenterService.TouchChannel(parent.Name);
                             }
-                            break;
-                        case CleanUpFFmpegSessions:
-                            _ffmpegSegmenterService.CleanUpSessions();
-                            break;
-                        case StartFFmpegSession startFFmpegSession:
-                            _logger.LogInformation(
-                                "Starting ffmpeg session for channel {Channel}",
-                                startFFmpegSession.ChannelNumber);
-
-                            if (!_ffmpegSegmenterService.ProcessExistsForChannel(startFFmpegSession.ChannelNumber))
-                            {
-                                var req = new GetPlayoutItemProcessByChannelNumber(
-                                    startFFmpegSession.ChannelNumber,
-                                    "segmenter",
-                                    startFFmpegSession.StartAtZero);
-                                Either<BaseError, Process> maybeProcess = await mediator.Send(req, cancellationToken);
-                                maybeProcess.Match(
-                                    process =>
-                                    {
-                                        if (_ffmpegSegmenterService.TryAdd(startFFmpegSession.ChannelNumber, process))
-                                        {
-                                            _logger.LogDebug(
-                                                "ffmpeg hls arguments {FFmpegArguments}",
-                                                string.Join(" ", process.StartInfo.ArgumentList));
-
-                                            process.Start();
-                                            process.EnableRaisingEvents = true;
-                                            process.Exited += (_, _) =>
-                                            {
-                                                if (process.ExitCode == 0)
-                                                {
-                                                    _channelWriter.TryWrite(
-                                                        new StartFFmpegSession(startFFmpegSession.ChannelNumber, true));
-                                                }
-                                                else
-                                                {
-                                                    _logger.LogDebug(
-                                                        "hls segmenter for channel {Channel} exited with code {ExitCode}",
-                                                        startFFmpegSession.ChannelNumber,
-                                                        process.ExitCode);
-                                                }
-                                            };
-                                        }
-                                    },
-                                    _ => { });
-                            }
 
                             break;
                     }
@@ -113,9 +59,6 @@ namespace ErsatzTV.Services
                      _logger.LogWarning(ex, "Failed to handle ffmpeg worker request");
                 }
             }
-            
-            // kill any running processes after cancellation
-            _ffmpegSegmenterService.KillAll();
         }
     }
 }

ErsatzTV/Startup.cs

@@ -7,6 +7,7 @@ using Blazored.LocalStorage;
 using Dapper;
 using ErsatzTV.Application;
 using ErsatzTV.Application.Channels.Queries;
+using ErsatzTV.Application.Streaming;
 using ErsatzTV.Application.Streaming.Commands;
 using ErsatzTV.Core;
 using ErsatzTV.Core.Emby;
@@ -300,6 +301,7 @@ namespace ErsatzTV
             services.AddScoped<IPlexPathReplacementService, PlexPathReplacementService>();
             services.AddScoped<IFFmpegStreamSelector, FFmpegStreamSelector>();
             services.AddScoped<FFmpegProcessService>();
+            services.AddScoped<HlsSessionWorker>();
             services.AddScoped<IGitHubApiClient, GitHubApiClient>();
             services.AddScoped<IHtmlSanitizer, HtmlSanitizer>(
                 _ =>
@@ -326,7 +328,6 @@ namespace ErsatzTV
             services.AddHostedService<WorkerService>();
             services.AddHostedService<SchedulerService>();
             services.AddHostedService<FFmpegWorkerService>();
-            services.AddHostedService<FFmpegSchedulerService>();
         }
 
         private void AddChannel<TMessageType>(IServiceCollection services)

docker/nvidia/Dockerfile

@@ -23,7 +23,7 @@ ARG INFO_VERSION="unknown"
 RUN dotnet publish -c release -o /app -r linux-x64 --self-contained false --no-restore /p:InformationalVersion=${INFO_VERSION}
 
 # final stage/image
-FROM jasongdove/ffmpeg:4.3-nvidia1804 AS runtime-base
+FROM jasongdove/ffmpeg:4.3-nvidia2004 AS runtime-base
 WORKDIR /app
 EXPOSE 8409
 COPY --from=build /app ./

docker/nvidia/ffmpeg.Dockerfile

@@ -1,6 +1,6 @@
 FROM mcr.microsoft.com/dotnet/aspnet:5.0-focal-amd64 AS dotnet-runtime
 
-FROM jrottenberg/ffmpeg:4.3-nvidia1804 AS runtime-base
+FROM jrottenberg/ffmpeg:4.3-nvidia2004 AS runtime-base
 COPY --from=dotnet-runtime /usr/share/dotnet /usr/share/dotnet
 RUN apt-get update \
     && DEBIAN_FRONTEND="noninteractive" apt-get install -y libicu-dev tzdata \

docs/index.md

@@ -10,5 +10,6 @@ Want to say thanks? Consider [sponsorship on GitHub](https://github.com/sponsors
 
 1. [Install ErsatzTV](user-guide/install.md)
 2. [Add Media Items](user-guide/add-media-items.md)
-3. [Create Channels](user-guide/create-channels.md)
-4. [Configure Clients](user-guide/configure-clients.md)
+3. [Create Collections](user-guide/create-collections.md)
+4. [Create Channels](user-guide/create-channels.md)
+5. [Configure Clients](user-guide/configure-clients.md)

docs/user-guide/add-media-items.md

@@ -194,26 +194,3 @@ Click `Add Path Replacement` to add a new path replacement, and enter the `Emby
 Click `Save Changes` after you have created all needed path replacements.
 
 ![Emby Path Replacements](../images/emby-media-source-path-replacements.png)
-
-## Collections
-
-ErsatzTV does not schedule individual media items; only collections of items can be scheduled.
-To create a collection, find the media items you would like to include and select them by clicking the selection button in the top left of the poster:
-
-![Poster Selection Button](../images/poster-selection-button.png)
-
-Then, add to a collection by clicking the `Add To Collection` button at the top of the page.
-
-![Add Selection To Collection](../images/add-selection-to-collection.png)
-
-In the `Add To Collection` dialog, either select an existing collection for the items, or enter a new collection name to create a collection and add all of the selected items in a single step.
-
-![Add To Collection Dialog](../images/add-to-collection-dialog.png)
-
----
-
-Big Buck Bunny: (c) copyright 2008, Blender Foundation / [www.bigbuckbunny.org](https://www.bigbuckbunny.org)
-
-Sintel: © copyright Blender Foundation | [www.sintel.org](https://www.sintel.org)
-
-Tears of Steel: (CC) Blender Foundation | [mango.blender.org](https://mango.blender.org)

docs/user-guide/create-collections.md

@@ -0,0 +1,65 @@
+## Collection Types
+
+ErsatzTV does not schedule individual media items; only collections of items can be scheduled. There are three (3) collection types:
+
+- `Collection`: contains manually-added items
+- `Smart Collection`: contains items from search results or imported Trakt Lists, and updates dynamically
+- `Multi Collection`: contains other Collections and Smart Collections.
+
+### Collections
+
+Collections are created manually by adding individual media items to it. There is no restriction on media type. A collection can contain a single media type, eg. movies or any combination of media types.
+The items to be added can be found by browsing your libraries or by using ErsatzTV's powerful Search feature. An empty collection can be created under `Lists` > `Collections` > `Add Collection`.
+
+To create a collection, find the media items you would like to include and select them by clicking the selection button in the top left of the poster:
+
+![Poster Selection Button](../images/poster-selection-button.png)
+
+Then, add to a collection by clicking the `Add To Collection` button at the top of the page.
+
+![Add Selection To Collection](../images/add-selection-to-collection.png)
+
+In the `Add To Collection` dialog, either select an existing collection for the items, or enter a new collection name to create a collection and add all of the selected items in a single step.
+
+![Add To Collection Dialog](../images/add-to-collection-dialog.png)
+
+### Smart Collections
+
+Smart Collections are created by saving searches or saving imported Trakt Lists.
+
+#### From Searches
+
+To create a smart collection, type a search query in the search box and press enter.
+If the result shown meets your expectations, save as a Smart Collection by clicking the `Save As` button.
+If it doesn't meet your expectations, refine the search query until it does and then save.
+
+#### From Imported Trakt Lists
+
+To import a Trakt List, navigate to the `Lists` > `Trakt Lists` page and click the `Add Trakt List` button.  Trakt lists can be imported by url or by `user/list`.
+
+- To re-download a Trakt List, simply add it again. There is no need to delete.
+- Unmatched item details are written to the log.
+- Trakt Lists can only be scheduled after being saved as a Smart Collection.
+
+To see matching items from an imported Trakt list, click the search button on the row of the Trakt List.
+
+![Trakt List Search](../images/trakt-list-search.png)
+
+### Multi Collections
+
+Multi Collections contain other Collections and/or Smart Collections. The primary purpose of these are to enable the scheduling of sets of Media Items in a controlled manner.
+Here we are referring to Movie Boxsets, e.g. X-Men Collection, Star Trek Collection and Before... Collection as well as related movies and tv show groups such as Arrowverse, MARVEL Cinematic Universe, Worlds of DC and Battlestar Galactica (Reboot).
+
+To Add a Multi Collection
+
+- Navigate to `Lists` > `Collections` and click the `Add Multi Collection` button
+- Give the Multi Collection a name
+- Add collections and/or smart collections as required and click `Add Multi Collection` to save
+
+---
+
+Big Buck Bunny: (c) copyright 2008, Blender Foundation / [www.bigbuckbunny.org](https://www.bigbuckbunny.org)
+
+Sintel: © copyright Blender Foundation | [www.sintel.org](https://www.sintel.org)
+
+Tears of Steel: (CC) Blender Foundation | [mango.blender.org](https://mango.blender.org)

docs/user-guide/search.md

@@ -71,6 +71,7 @@ The following fields are available for searching artists:
 The following fields are available for searching music videos:
 
 - `title`: The music video title
+- `album`: The music video album
 - `genre`: The music video genre
 - `library_name`: The name of the library that contains the music video
 - `language`: The music video audio stream language

mkdocs.yml

@@ -3,6 +3,7 @@ nav:
   - 'Quick Start':
     - 'Install ErsatzTV': 'user-guide/install.md'
     - 'Add Media Items': 'user-guide/add-media-items.md'
+    - 'Create Collections': 'user-guide/create-collections.md'
     - 'Create Channels': 'user-guide/create-channels.md'
     - 'Configure Clients': 'user-guide/configure-clients.md'
   - 'Advanced':