fix external ssa subtitles from media servers (#2450)

CHANGELOG.md

@@ -65,6 +65,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Fix fallback filler duration on mirror channels
 - Fix slow startup caused by check for overlapping playout items
 - Fix green line in *most* cases when overlaying content using NVIDIA acceleration and H264 output
+- Fix non-SRT (e.g. SSA/ASS) external subtitle playback from media servers
 
 ### Changed
 - Filler presets: use separate text fields for `hours`, `minutes` and `seconds` duration

ErsatzTV.Application/Streaming/Queries/GetSeekTextSubtitleProcess.cs

@@ -1,6 +1,7 @@
+using ErsatzTV.Application.Subtitles;
 using ErsatzTV.Core;
 
 namespace ErsatzTV.Application.Streaming;
 
-public record GetSeekTextSubtitleProcess(string SubtitlePath, TimeSpan Seek)
+public record GetSeekTextSubtitleProcess(SubtitlePathAndCodec PathAndCodec, TimeSpan Seek)
     : IRequest<Either<BaseError, SeekTextSubtitleProcess>>;

ErsatzTV.Application/Streaming/Queries/GetSeekTextSubtitleProcessHandler.cs

@@ -31,7 +31,8 @@ public class GetSeekTextSubtitleProcessHandler(
     {
         Command process = await ffmpegProcessService.SeekTextSubtitle(
             ffmpegPath,
-            request.SubtitlePath,
+            request.PathAndCodec.Path,
+            request.PathAndCodec.Codec,
             request.Seek);
 
         return new SeekTextSubtitleProcess(process);

ErsatzTV.Application/Subtitles/Queries/GetSubtitlePathById.cs

@@ -2,4 +2,4 @@ using ErsatzTV.Core;
 
 namespace ErsatzTV.Application.Subtitles.Queries;
 
-public record GetSubtitlePathById(int Id) : IRequest<Either<BaseError, string>>;
+public record GetSubtitlePathById(int Id) : IRequest<Either<BaseError, SubtitlePathAndCodec>>;

ErsatzTV.Application/Subtitles/Queries/GetSubtitlePathByIdHandler.cs

@@ -9,9 +9,9 @@ using Microsoft.EntityFrameworkCore;
 namespace ErsatzTV.Application.Subtitles.Queries;
 
 public class GetSubtitlePathByIdHandler(IDbContextFactory<TvContext> dbContextFactory)
-    : IRequestHandler<GetSubtitlePathById, Either<BaseError, string>>
+    : IRequestHandler<GetSubtitlePathById, Either<BaseError, SubtitlePathAndCodec>>
 {
-    public async Task<Either<BaseError, string>> Handle(
+    public async Task<Either<BaseError, SubtitlePathAndCodec>> Handle(
         GetSubtitlePathById request,
         CancellationToken cancellationToken)
     {
@@ -22,33 +22,35 @@ public class GetSubtitlePathByIdHandler(IDbContextFactory<TvContext> dbContextFa
 
         foreach (var subtitle in maybeSubtitle)
         {
+            string path = subtitle.Path;
+
             if (subtitle is { SubtitleKind: SubtitleKind.Embedded, IsExtracted: true })
             {
-                return Path.Combine(FileSystemLayout.SubtitleCacheFolder, subtitle.Path);
+                path = Path.Combine(FileSystemLayout.SubtitleCacheFolder, subtitle.Path);
             }
 
             foreach (string plexUrl in await GetPlexUrl(request.Id, dbContext, maybeSubtitle))
             {
-                return plexUrl;
+                path = plexUrl;
             }
 
             foreach (string jellyfinUrl in await GetJellyfinUrl(request.Id, dbContext, maybeSubtitle))
             {
-                return jellyfinUrl;
+                path = jellyfinUrl;
             }
 
             foreach (string embyUrl in await GetEmbyUrl(request.Id, dbContext, maybeSubtitle))
             {
-                return embyUrl;
+                path = embyUrl;
             }
 
-            return subtitle.Path;
+            return new SubtitlePathAndCodec(path, subtitle.Codec);
         }
 
         return BaseError.New($"Unable to locate subtitle with id {request.Id}");
     }
 
-        protected static async Task<Option<string>> GetPlexUrl(
+    protected static async Task<Option<string>> GetPlexUrl(
         int subtitleId,
         TvContext dbContext,
         Option<Subtitle> maybeSubtitle)

ErsatzTV.Application/Subtitles/SubtitlePathAndCodec.cs

@@ -0,0 +1,3 @@
+namespace ErsatzTV.Application.Subtitles;
+
+public record SubtitlePathAndCodec(string Path, string Codec);

ErsatzTV.Core/FFmpeg/FFmpegLibraryProcessService.cs

@@ -967,7 +967,7 @@ public class FFmpegLibraryProcessService : IFFmpegProcessService
             watermarkWidthPercent,
             cancellationToken);
 
-    public async Task<Command> SeekTextSubtitle(string ffmpegPath, string inputFile, TimeSpan seek)
+    public async Task<Command> SeekTextSubtitle(string ffmpegPath, string inputFile, string codec, TimeSpan seek)
     {
         var videoInputFile = new VideoInputFile(
             inputFile,
@@ -975,7 +975,7 @@ public class FFmpegLibraryProcessService : IFFmpegProcessService
             {
                 new(
                     0,
-                    string.Empty,
+                    codec,
                     string.Empty,
                     None,
                     ColorParams.Default,
@@ -1002,7 +1002,7 @@ public class FFmpegLibraryProcessService : IFFmpegProcessService
             FileSystemLayout.FontsCacheFolder,
             ffmpegPath);
 
-        FFmpegPipeline pipeline = pipelineBuilder.Seek(inputFile, seek);
+        FFmpegPipeline pipeline = pipelineBuilder.Seek(inputFile, codec, seek);
 
         return GetCommand(ffmpegPath, videoInputFile, None, None, None, None, pipeline, false);
     }

ErsatzTV.Core/Interfaces/FFmpeg/IFFmpegProcessService.cs

@@ -90,5 +90,5 @@ public interface IFFmpegProcessService
         int watermarkWidthPercent,
         CancellationToken cancellationToken);
 
-    Task<Command> SeekTextSubtitle(string ffmpegPath, string inputFile, TimeSpan seek);
+    Task<Command> SeekTextSubtitle(string ffmpegPath, string inputFile, string codec, TimeSpan seek);
 }

ErsatzTV.FFmpeg/Pipeline/IPipelineBuilder.cs

@@ -3,7 +3,7 @@ namespace ErsatzTV.FFmpeg.Pipeline;
 public interface IPipelineBuilder
 {
     FFmpegPipeline Resize(string outputFile, FrameSize scaledSize);
-    FFmpegPipeline Seek(string inputFile, TimeSpan seek);
+    FFmpegPipeline Seek(string inputFile, string codec, TimeSpan seek);
     FFmpegPipeline Concat(ConcatInputFile concatInputFile, FFmpegState ffmpegState);
     FFmpegPipeline WrapSegmenter(ConcatInputFile concatInputFile, FFmpegState ffmpegState);
     FFmpegPipeline Build(FFmpegState ffmpegState, FrameState desiredState);

ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs

@@ -75,12 +75,14 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
         return new FFmpegPipeline(pipelineSteps, false);
     }
 
-    public FFmpegPipeline Seek(string inputFile, TimeSpan seek)
+    public FFmpegPipeline Seek(string inputFile, string codec, TimeSpan seek)
     {
         IPipelineStep outputFormat = Path.GetExtension(inputFile).ToLowerInvariant() switch
         {
             ".ass" or ".ssa" => new OutputFormatAss(),
             ".vtt" => new OutputFormatWebVtt(),
+            _ when codec.ToLowerInvariant() is "ass" or "ssa" => new OutputFormatAss(),
+            _ when codec.ToLowerInvariant() is "vtt" => new OutputFormatWebVtt(),
             _ => new OutputFormatSrt()
         };
 

ErsatzTV/Controllers/InternalController.cs

@@ -7,6 +7,7 @@ using ErsatzTV.Application.Jellyfin;
 using ErsatzTV.Application.MediaItems;
 using ErsatzTV.Application.Plex;
 using ErsatzTV.Application.Streaming;
+using ErsatzTV.Application.Subtitles;
 using ErsatzTV.Application.Subtitles.Queries;
 using ErsatzTV.Core;
 using ErsatzTV.Core.FFmpeg;
@@ -202,21 +203,23 @@ public class InternalController : ControllerBase
     [HttpGet("/media/subtitle/{id:int}")]
     public async Task<IActionResult> GetSubtitle(int id, [FromQuery] long? seekToMs)
     {
-        Either<BaseError, string> maybePath = await _mediator.Send(new GetSubtitlePathById(id));
+        Either<BaseError, SubtitlePathAndCodec> maybePath = await _mediator.Send(new GetSubtitlePathById(id));
 
-        foreach (string path in maybePath.RightToSeq())
+        foreach (SubtitlePathAndCodec pathAndCodec in maybePath.RightToSeq())
         {
-            string mimeType = Path.GetExtension(path).ToLowerInvariant() switch
+            string mimeType = Path.GetExtension(pathAndCodec.Path ?? string.Empty).ToLowerInvariant() switch
             {
                 ".ass" or ".ssa" => "text/x-ssa",
                 ".vtt" => "text/vtt",
+                _ when pathAndCodec.Codec.ToLowerInvariant() is "ass" or "ssa" => "text/x-ssa",
+                _ when pathAndCodec.Codec.ToLowerInvariant() is "vtt" => "text/vtt",
                 _ => "application/x-subrip"
             };
 
             if (seekToMs is > 0)
             {
                 Either<BaseError, SeekTextSubtitleProcess> maybeProcess = await _mediator.Send(
-                    new GetSeekTextSubtitleProcess(path, TimeSpan.FromMilliseconds(seekToMs.Value)));
+                    new GetSeekTextSubtitleProcess(pathAndCodec, TimeSpan.FromMilliseconds(seekToMs.Value)));
                 foreach (SeekTextSubtitleProcess processModel in maybeProcess.RightToSeq())
                 {
                     Command command = processModel.Process;
@@ -250,12 +253,12 @@ public class InternalController : ControllerBase
                 return new NotFoundResult();
             }
 
-            if (path.StartsWith("http", StringComparison.OrdinalIgnoreCase))
+            if (pathAndCodec.Path.StartsWith("http", StringComparison.OrdinalIgnoreCase))
             {
-                return new RedirectResult(path);
+                return new RedirectResult(pathAndCodec.Path);
             }
 
-            return new PhysicalFileResult(path, mimeType);
+            return new PhysicalFileResult(pathAndCodec.Path, mimeType);
         }
 
         return new NotFoundResult();