Generate thumbnails

.gitignore

@@ -1,3 +1,4 @@
 bin/
 obj/
 .idea/
+thumbs/

NostrStreamer/Controllers/PlaylistController.cs

@@ -15,9 +15,10 @@ public class PlaylistController : Controller
     private readonly SrsApi _srsApi;
     private readonly ViewCounter _viewCounter;
     private readonly StreamManagerFactory _streamManagerFactory;
+    private readonly ThumbnailService _thumbnailService;
 
     public PlaylistController(Config config, ILogger<PlaylistController> logger,
-        HttpClient client, SrsApi srsApi, ViewCounter viewCounter, StreamManagerFactory streamManagerFactory)
+        HttpClient client, SrsApi srsApi, ViewCounter viewCounter, StreamManagerFactory streamManagerFactory, ThumbnailService thumbnailService)
     {
         _config = config;
         _logger = logger;
@@ -25,6 +26,7 @@ public class PlaylistController : Controller
         _srsApi = srsApi;
         _viewCounter = viewCounter;
         _streamManagerFactory = streamManagerFactory;
+        _thumbnailService = thumbnailService;
     }
 
     [HttpGet("{variant}/{id}.m3u8")]
@@ -80,20 +82,29 @@ public class PlaylistController : Controller
         }
     }
 
-    [HttpGet("{pubkey}.png")]
-    public async Task GetPreview([FromRoute] string pubkey)
+    [HttpGet("{id}.jpg")]
+    public async Task GetPreview([FromRoute] Guid id)
     {
         try
         {
-            var streamManager = await _streamManagerFactory.ForCurrentStream(pubkey);
-            var userStream = streamManager.GetStream();
-
-            var path = $"/{userStream.Endpoint.App}/{userStream.User.StreamKey}.png";
-            await ProxyRequest(path);
+            var stream = _thumbnailService.GetThumbnail(id);
+            if (stream != default)
+            {
+                Response.ContentLength = stream.Length;
+                Response.ContentType = "image/jpg";
+                Response.Headers.CacheControl = "public, max-age=60";
+                await Response.StartAsync();
+                await stream.CopyToAsync(Response.Body);
+                await Response.CompleteAsync();
+            }
+            else
+            {
+                Response.StatusCode = 404;
+            }
         }
         catch (Exception ex)
         {
-            _logger.LogWarning("Failed to get preview image for {pubkey} {message}", pubkey, ex.Message);
+            _logger.LogWarning("Failed to get preview image for {id} {message}", id, ex.Message);
             Response.StatusCode = 404;
         }
     }

NostrStreamer/NostrStreamer.csproj

@@ -29,6 +29,7 @@
     </ItemGroup>
 
     <ItemGroup>
+      <PackageReference Include="FFMpegCore" Version="5.1.0" />
       <PackageReference Include="Google.Protobuf" Version="3.23.3" />
       <PackageReference Include="Grpc.Net.Client" Version="2.54.0" />
       <PackageReference Include="Grpc.Tools" Version="2.56.0">

NostrStreamer/Program.cs

@@ -56,6 +56,8 @@ internal static class Program
         services.AddTransient<StreamEventBuilder>();
         services.AddTransient<StreamManagerFactory>();
         services.AddTransient<UserService>();
+        services.AddTransient<ThumbnailService>();
+        services.AddHostedService<ThumbnailGenerator>();
         
         // lnd services
         services.AddSingleton<LndNode>();

NostrStreamer/Services/StreamEventBuilder.cs

@@ -38,7 +38,7 @@ public class StreamEventBuilder
             new("title", user.Title ?? ""),
             new("summary", user.Summary ?? ""),
             new("streaming", new Uri(_config.DataHost, $"{user.PubKey}.m3u8").ToString()),
-            new("image", user.Image ?? new Uri(_config.DataHost, $"{user.PubKey}.png").ToString()),
+            new("image", string.IsNullOrEmpty(user.Image) ? new Uri(_config.DataHost, $"{stream.Id}.jpg").ToString() : user.Image),
             new("status", status),
             new("p", user.PubKey, "", "host"),
             new("relays", _config.Relays),

NostrStreamer/Services/ThumbnailGenerator.cs

@@ -0,0 +1,47 @@
+using Microsoft.EntityFrameworkCore;
+using NostrStreamer.Database;
+
+namespace NostrStreamer.Services;
+
+public class ThumbnailGenerator : BackgroundService
+{
+    private readonly IServiceScopeFactory _scopeFactory;
+    private readonly ILogger<ThumbnailGenerator> _logger;
+    
+    public ThumbnailGenerator(IServiceScopeFactory scopeFactory, ILogger<ThumbnailGenerator> logger)
+    {
+        _scopeFactory = scopeFactory;
+        _logger = logger;
+    }
+    
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                using var scope = _scopeFactory.CreateScope();
+                var db = scope.ServiceProvider.GetRequiredService<StreamerContext>();
+                var gen = scope.ServiceProvider.GetRequiredService<ThumbnailService>();
+
+                var streams = await db.Streams
+                    .AsNoTracking()
+                    .Include(a => a.Endpoint)
+                    .Include(a => a.User)
+                    .Where(a => a.State == UserStreamState.Live)
+                    .ToListAsync(cancellationToken: stoppingToken);
+
+                foreach (var stream in streams)
+                {
+                    await gen.GenerateThumb(stream);
+                }
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning("Failed to generate thumbnail {msg}", ex.Message);
+            }
+
+            await Task.Delay(TimeSpan.FromMinutes(1), stoppingToken);
+        }
+    }
+}

NostrStreamer/Services/ThumbnailService.cs

@@ -0,0 +1,50 @@
+using FFMpegCore;
+using NostrStreamer.Database;
+
+namespace NostrStreamer.Services;
+
+public class ThumbnailService
+{
+    private const string Dir = "thumbs";
+    private readonly Config _config;
+    private readonly ILogger<ThumbnailService> _logger;
+
+    public ThumbnailService(Config config, ILogger<ThumbnailService> logger)
+    {
+        _config = config;
+        _logger = logger;
+        if (!Directory.Exists(Dir))
+        {
+            Directory.CreateDirectory(Dir);
+        }
+    }
+
+    public async Task GenerateThumb(UserStream stream)
+    {
+        var path = MapPath(stream.Id);
+        try
+        {
+            var cmd = FFMpegArguments
+                .FromUrlInput(new Uri(_config.RtmpHost, $"{stream.Endpoint.App}/{stream.User.StreamKey}"))
+                .OutputToFile(path, true, o => { o.ForceFormat("image2").WithCustomArgument("-vframes 1"); });
+
+            _logger.LogInformation("Running command {cmd}", cmd.Arguments);
+            await cmd.ProcessAsynchronously();
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning("Failed to generate thumbnail {msg}", ex.Message);
+        }
+    }
+
+    public System.IO.Stream? GetThumbnail(Guid id)
+    {
+        var path = MapPath(id);
+        return File.Exists(path) ? new FileStream(path, FileMode.Open, FileAccess.Read) : null;
+    }
+
+    private string MapPath(Guid id)
+    {
+        return Path.Combine(Dir, $"{id}.jpg");
+    }
+}

docker/srs-origin.conf

@@ -36,20 +36,4 @@ vhost hls.zap.stream {
         on_unpublish http://10.100.2.226:5295/api/srs;
         on_hls http://10.100.2.226:5295/api/srs;
     }
-    
-    transcode {
-        enabled     on;
-        ffmpeg      ./objs/ffmpeg/bin/ffmpeg;
-        
-        engine {
-            enabled         on;
-            vcodec          png;
-            acodec          an;
-            vparams {
-                vframes 1;
-            }
-            oformat         image2;
-            output          ./objs/nginx/html/[app]/[stream].png;
-        }
-    }
 }