From 5b100483899869f776a0aa9edae5ca0d2735bd8c Mon Sep 17 00:00:00 2001
From: Jason Dove <1695733+jasongdove@users.noreply.github.com>
Date: Thu, 30 Oct 2025 14:11:13 -0500
Subject: [PATCH] fix seeking content with dts audio

---
 CHANGELOG.md                                  |  1 +
 ErsatzTV.FFmpeg/Decoder/DecoderDtsCoreOnly.cs | 24 +++++++++++++++++++
 ErsatzTV.FFmpeg/Format/AudioFormat.cs         |  1 +
 .../Pipeline/PipelineBuilderBase.cs           |  9 +++++++
 4 files changed, 35 insertions(+)
 create mode 100644 ErsatzTV.FFmpeg/Decoder/DecoderDtsCoreOnly.cs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d73b8c608..b1e325cc4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   - This caused playout build errors like "Unable to locate history for playout item"
 - Fix crashes due to invalid smart collection searches, e.g. `smart_collection:"this collection does not exist"`
 - Fix UI crash when editing block playout that has default deco
+- Fix playback failure when seeking content with certain DTS audio (e.g. DTS-HD MA)
 
 ## [25.8.0] - 2025-10-26
 ### Added
diff --git a/ErsatzTV.FFmpeg/Decoder/DecoderDtsCoreOnly.cs b/ErsatzTV.FFmpeg/Decoder/DecoderDtsCoreOnly.cs
new file mode 100644
index 000000000..1bc18d7f1
--- /dev/null
+++ b/ErsatzTV.FFmpeg/Decoder/DecoderDtsCoreOnly.cs
@@ -0,0 +1,24 @@
+using ErsatzTV.FFmpeg.Environment;
+using ErsatzTV.FFmpeg.InputOption;
+
+namespace ErsatzTV.FFmpeg.Decoder;
+
+public class DecoderDtsCoreOnly : IInputOption
+{
+    public EnvironmentVariable[] EnvironmentVariables => [];
+    public string[] GlobalOptions => [];
+    public string[] FilterOptions => [];
+    public string[] OutputOptions => [];
+
+    public string[] InputOptions(InputFile inputFile) => ["-c:a", "dts", "-core_only", "true"];
+
+    public FrameState NextState(FrameState currentState) => currentState;
+
+    public bool AppliesTo(AudioInputFile audioInputFile) => true;
+
+    public bool AppliesTo(VideoInputFile videoInputFile) => false;
+
+    public bool AppliesTo(ConcatInputFile concatInputFile) => false;
+
+    public bool AppliesTo(GraphicsEngineInput graphicsEngineInput) => false;
+}
diff --git a/ErsatzTV.FFmpeg/Format/AudioFormat.cs b/ErsatzTV.FFmpeg/Format/AudioFormat.cs
index 79331b9f3..9320ddbd8 100644
--- a/ErsatzTV.FFmpeg/Format/AudioFormat.cs
+++ b/ErsatzTV.FFmpeg/Format/AudioFormat.cs
@@ -5,6 +5,7 @@ public static class AudioFormat
     public const string Aac = "aac";
     public const string Ac3 = "ac3";
     public const string AacLatm = "aac-latm";
+    public const string Dts = "dts";
 
     public const string Copy = "copy";
 }
diff --git a/ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs b/ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs
index 79091148b..9f2beeff3 100644
--- a/ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs
+++ b/ErsatzTV.FFmpeg/Pipeline/PipelineBuilderBase.cs
@@ -454,6 +454,15 @@ public abstract class PipelineBuilderBase : IPipelineBuilder
         AudioInputFile audioInputFile,
         List<IPipelineStep> pipelineSteps)
     {
+        // workaround for seeking with dts; certain seeks will change format when decoding (e.g. s16p to s32p)
+        foreach (TimeSpan _ in ffmpegState.Start.Filter(s => s > TimeSpan.Zero))
+        {
+            if (audioInputFile.Streams.OfType<AudioStream>() .Any(s => s.Codec == AudioFormat.Dts))
+            {
+                audioInputFile.AddOption(new DecoderDtsCoreOnly());
+            }
+        }
+
         // always need to specify audio codec so ffmpeg doesn't default to a codec we don't want
         foreach (IEncoder step in AvailableEncoders.ForAudioFormat(ffmpegState, audioInputFile.DesiredState, _logger))
         {