From 4de9251f95780eeafee64ceca473fa792586a040 Mon Sep 17 00:00:00 2001
From: Andy <scene@scene.com>
Date: Wed, 30 Jul 2025 21:39:34 +0000
Subject: [PATCH] =?UTF-8?q?feat(tracks):=20=E2=9C=A8=20Add=20duration=20fi?=
 =?UTF-8?q?x=20handling=20for=20video=20and=20hybrid=20tracks?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
 unshackle/commands/dl.py        |  4 ++++
 unshackle/core/tracks/tracks.py | 40 ++++++++++++++++++++-------------
 unshackle/core/tracks/video.py  |  2 ++
 3 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/unshackle/commands/dl.py b/unshackle/commands/dl.py
index 54661ca..ac18949 100644
--- a/unshackle/commands/dl.py
+++ b/unshackle/commands/dl.py
@@ -959,6 +959,9 @@ class dl:
                                 # Create track pair for this resolution
                                 resolution_tracks = [hdr10_track, matching_dv]
 
+                                for track in resolution_tracks:
+                                    track.needs_duration_fix = True
+
                                 # Run the hybrid processing for this resolution
                                 Hybrid(resolution_tracks, self.service)
 
@@ -982,6 +985,7 @@ class dl:
                                 hybrid_track = deepcopy(hdr10_track)
                                 hybrid_track.path = hybrid_output_path
                                 hybrid_track.range = Video.Range.DV  # It's now a DV track
+                                hybrid_track.needs_duration_fix = True
                                 task_tracks.videos = [hybrid_track]
 
                                 multiplex_tasks.append((task_id, task_tracks))
diff --git a/unshackle/core/tracks/tracks.py b/unshackle/core/tracks/tracks.py
index 40cf8fc..a680021 100644
--- a/unshackle/core/tracks/tracks.py
+++ b/unshackle/core/tracks/tracks.py
@@ -331,21 +331,31 @@ class Tracks:
             if not vt.path or not vt.path.exists():
                 raise ValueError("Video Track must be downloaded before muxing...")
             events.emit(events.Types.TRACK_MULTIPLEX, track=vt)
-            cl.extend(
-                [
-                    "--language",
-                    f"0:{vt.language}",
-                    "--default-track",
-                    f"0:{i == 0}",
-                    "--original-flag",
-                    f"0:{vt.is_original_lang}",
-                    "--compression",
-                    "0:none",  # disable extra compression
-                    "(",
-                    str(vt.path),
-                    ")",
-                ]
-            )
+
+            # Prepare base arguments
+            video_args = [
+                "--language",
+                f"0:{vt.language}",
+                "--default-track",
+                f"0:{i == 0}",
+                "--original-flag",
+                f"0:{vt.is_original_lang}",
+                "--compression",
+                "0:none",  # disable extra compression
+            ]
+
+            # Add FPS fix if needed (typically for hybrid mode to prevent sync issues)
+            if hasattr(vt, "needs_duration_fix") and vt.needs_duration_fix and vt.fps:
+                video_args.extend(
+                    [
+                        "--default-duration",
+                        f"0:{vt.fps}fps" if isinstance(vt.fps, str) else f"0:{vt.fps:.3f}fps",
+                        "--fix-bitstream-timing-information",
+                        "0:1",
+                    ]
+                )
+
+            cl.extend(video_args + ["(", str(vt.path), ")"])
 
         for i, at in enumerate(self.audio):
             if not at.path or not at.path.exists():
diff --git a/unshackle/core/tracks/video.py b/unshackle/core/tracks/video.py
index de1d77a..9069692 100644
--- a/unshackle/core/tracks/video.py
+++ b/unshackle/core/tracks/video.py
@@ -237,6 +237,8 @@ class Video(Track):
         except Exception as e:
             raise ValueError("Expected fps to be a number, float, or a string as numerator/denominator form, " + str(e))
 
+        self.needs_duration_fix = False
+
     def __str__(self) -> str:
         return " | ".join(
             filter(