diff --git a/frontend/src/api.ts b/frontend/src/api.ts
index a07e3b8..848d1e6 100644
--- a/frontend/src/api.ts
+++ b/frontend/src/api.ts
@@ -44,19 +44,19 @@ export function getVideoPreviewUrl(url: string): string {
 
 export function getVideoSourceAttributes(path: string | null | undefined): VideoSourceAttributes {
   if (!path) {
-    return { type: 'video/mp4; codecs="hvc1"', codecs: 'hvc1' };
+    return { type: 'video/mp4', codecs: 'hvc1' };
   }
 
   if (/\.webm$/i.test(path)) {
-    return { type: 'video/webm; codecs="av01"', codecs: 'av01' };
+    return { type: 'video/webm', codecs: 'av1' };
   }
 
   if (/\.mp4$/i.test(path) || /\.m4v$/i.test(path)) {
-    return { type: 'video/mp4; codecs="hvc1"', codecs: 'hvc1' };
+    return { type: 'video/mp4', codecs: 'hvc1' };
   }
 
   if (/\.mov$/i.test(path)) {
-    return { type: 'video/quicktime; codecs="hvc1"', codecs: 'hvc1' };
+    return { type: 'video/quicktime', codecs: 'hvc1' };
   }
 
   if (/\.avi$/i.test(path)) {
@@ -67,7 +67,7 @@ export function getVideoSourceAttributes(path: string | null | undefined): Video
     return { type: 'video/x-matroska', codecs: '' };
   }
 
-  return { type: 'video/mp4; codecs="hvc1"', codecs: 'hvc1' };
+  return { type: 'video/mp4', codecs: 'hvc1' };
 }
 
 /**
diff --git a/mediahive/hivescan/showreel.py b/mediahive/hivescan/showreel.py
index a6e4e1f..242848f 100644
--- a/mediahive/hivescan/showreel.py
+++ b/mediahive/hivescan/showreel.py
@@ -33,6 +33,8 @@ async def _subprocess_exec(*args, **kwargs):
 # Showreel timestamp positions in seconds (5, 10, 15, 20, 25 minutes)
 SHOWREEL_TIMESTAMPS = [5 * 60, 10 * 60, 15 * 60, 20 * 60, 25 * 60]
 REEL_SOURCE_EXTENSIONS = [".webm", ".mp4"]
+# Temporary rollout switch: keep platform-native MP4/H.265 path available but disabled.
+ENABLE_PLATFORM_NATIVE_REELS = False
 
 
 def get_reel_source_extensions() -> list[str]:
@@ -52,11 +54,15 @@ def _to_media_path(path: Path, media_root: Optional[Path] = None) -> str:
 
 def get_reel_extension() -> str:
     """Return the platform-native reel file extension."""
+    if not ENABLE_PLATFORM_NATIVE_REELS:
+        return ".webm"
     return ".mp4" if sys.platform == "darwin" else ".webm"
 
 
 async def get_reel_video_encoder() -> str:
     """Return the platform-native reel video encoder."""
+    if not ENABLE_PLATFORM_NATIVE_REELS:
+        return await get_av1_encoder()
     if sys.platform == "darwin":
         return "libx265"
     return await get_av1_encoder()
@@ -73,6 +79,8 @@ def get_reel_video_options(encoder: str) -> list[str]:
 
 def get_reel_audio_options() -> list[str]:
     """Return ffmpeg audio and container options for the current platform."""
+    if not ENABLE_PLATFORM_NATIVE_REELS:
+        return ["-c:a", "libopus", "-ac", "2", "-b:a", "128k"]
     if sys.platform == "darwin":
         return ["-c:a", "aac", "-ac", "2", "-b:a", "128k", "-movflags", "+faststart"]
     return ["-c:a", "libopus", "-ac", "2", "-b:a", "128k"]
diff --git a/mediahive/models/__init__.py b/mediahive/models/__init__.py
new file mode 100644
index 0000000..0402b2d
--- /dev/null
+++ b/mediahive/models/__init__.py
@@ -0,0 +1 @@
+"""Shared data/protocol models for MediaHive."""
diff --git a/mediahive/winmain.py b/mediahive/winmain.py
index 5409652..b48c6e5 100644
--- a/mediahive/winmain.py
+++ b/mediahive/winmain.py
@@ -28,6 +28,8 @@ import webview
 from mediahive.__main__ import resolve_media_root
 from mediahive.config import load_config, save_config
 
+logger = logging.getLogger("mediahive.winmain")
+
 BACKEND_HOST = "127.0.0.1"
 BACKEND_PORT = 8420
 HEALTH_TIMEOUT = 2  # seconds
@@ -669,6 +671,19 @@ def _icon_path() -> str | None:
     return str(ico) if ico.exists() else None
 
 
+def _webview_start_kwargs() -> dict[str, str]:
+    """Return platform-specific pywebview startup kwargs."""
+    # On macOS, force Qt backend so pywebview uses Chromium/WebEngine instead of WKWebView.
+    if sys.platform == "darwin":
+        return {"gui": "qt"}
+    return {}
+
+
+def _selected_webview_backend() -> str:
+    """Return the configured pywebview GUI backend name for logging."""
+    return _webview_start_kwargs().get("gui", "default")
+
+
 def _run_initial_setup() -> str | None:
     """Show a setup window, prompt for a folder, then close and return the path.
 
@@ -691,7 +706,7 @@ def _run_initial_setup() -> str | None:
             chosen.append(result[0])
         window.destroy()
 
-    webview.start(func=on_shown, icon=_icon_path())
+    webview.start(func=on_shown, icon=_icon_path(), **_webview_start_kwargs())
     return chosen[0] if chosen else None
 
 
@@ -766,6 +781,7 @@ def winmain() -> None:
         raise RuntimeError(f"Backend did not become ready within {HEALTH_TIMEOUT}s")
 
     api = JsApi()
+    logger.info("Configured pywebview backend: %s", _selected_webview_backend())
     window = webview.create_window(
         title="MediaHive",
         url=backend_url,
@@ -778,11 +794,18 @@ def winmain() -> None:
 
     def on_shown() -> None:
         api._window = window
+        try:
+            user_agent = window.evaluate_js("navigator.userAgent")
+            if isinstance(user_agent, str):
+                logger.info("Embedded webview user agent: %s", user_agent)
+        except Exception as exc:
+            logger.warning("Could not read embedded user agent: %s", exc)
+
         nonlocal poll_thread
         if poll_thread is None and _supports_gamepad_remote():
             poll_thread = _start_gamepad_remote(poll_stop, mediaroot)
 
-    webview.start(func=on_shown, icon=_icon_path())
+    webview.start(func=on_shown, icon=_icon_path(), **_webview_start_kwargs())
 
     poll_stop.set()
     if poll_thread is not None:
diff --git a/pyproject.toml b/pyproject.toml
index 55d3827..5c189bc 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,7 +46,10 @@ parse-torrent-title = { git = "https://github.com/platelminto/parse-torrent-titl
 
 [project.optional-dependencies]
 gui = [
-    "pywebview>=6.2.1",
+    "pywebview>=6.2.1; platform_system != 'Darwin'",
+    "pywebview[qt5]>=6.2.1; platform_system == 'Darwin'",
+    "qtpy>=2.4.1; platform_system == 'Darwin'",
+    "PyQt5>=5.15.11; platform_system == 'Darwin'",
     "pythonnet>=3.1.0rc0; platform_system == 'Windows' and python_version >= '3.14'",
     "pyinstaller>=6.0",
 ]
diff --git a/scripts/MediaHive.spec b/scripts/MediaHive.spec
index 83c5551..c42f60b 100644
--- a/scripts/MediaHive.spec
+++ b/scripts/MediaHive.spec
@@ -36,41 +36,57 @@ if _icon_win.exists():
 if _icon_mac.exists():
     _datas.append((str(_icon_mac), "mediahive/assets"))
 
+_hiddenimports = [
+    # uvicorn dynamic imports
+    "uvicorn.logging",
+    "uvicorn.loops",
+    "uvicorn.loops.auto",
+    "uvicorn.loops.asyncio",
+    "uvicorn.protocols",
+    "uvicorn.protocols.http",
+    "uvicorn.protocols.http.auto",
+    "uvicorn.protocols.http.h11_impl",
+    "uvicorn.protocols.websockets",
+    "uvicorn.protocols.websockets.auto",
+    "uvicorn.protocols.websockets.websockets_impl",
+    "uvicorn.lifespan",
+    "uvicorn.lifespan.on",
+    # mediahive & hivescan modules imported at runtime
+    "mediahive.server",
+    "mediahive.hivescan.scanner",
+    "mediahive.hivescan.indexer",
+    "mediahive.hivescan.scanning",
+    "mediahive.hivescan.images",
+    "mediahive.hivescan.showreel",
+    "mediahive.hivescan.tmdb_client",
+    # async / ASGI internals
+    "anyio",
+    "anyio._backends._asyncio",
+    "starlette.routing",
+    # msgspec TOML write backend
+    "tomli_w",
+]
+
+if sys.platform == "darwin":
+    _hiddenimports.extend(
+        [
+            # pywebview Qt backend selected dynamically via webview.start(gui="qt")
+            "webview.platforms.qt",
+            "qtpy",
+            "PyQt5",
+            "PyQt5.QtCore",
+            "PyQt5.QtGui",
+            "PyQt5.QtWidgets",
+            "PyQt5.QtWebEngineWidgets",
+        ]
+    )
+
 a = Analysis(
     [mediahive.winmain.__file__],
     pathex=[],
     binaries=_binaries,
     datas=_datas,
-    hiddenimports=[
-        # uvicorn dynamic imports
-        "uvicorn.logging",
-        "uvicorn.loops",
-        "uvicorn.loops.auto",
-        "uvicorn.loops.asyncio",
-        "uvicorn.protocols",
-        "uvicorn.protocols.http",
-        "uvicorn.protocols.http.auto",
-        "uvicorn.protocols.http.h11_impl",
-        "uvicorn.protocols.websockets",
-        "uvicorn.protocols.websockets.auto",
-        "uvicorn.protocols.websockets.websockets_impl",
-        "uvicorn.lifespan",
-        "uvicorn.lifespan.on",
-        # mediahive & hivescan modules imported at runtime
-        "mediahive.server",
-        "mediahive.hivescan.scanner",
-        "mediahive.hivescan.indexer",
-        "mediahive.hivescan.scanning",
-        "mediahive.hivescan.images",
-        "mediahive.hivescan.showreel",
-        "mediahive.hivescan.tmdb_client",
-        # async / ASGI internals
-        "anyio",
-        "anyio._backends._asyncio",
-        "starlette.routing",
-        # msgspec TOML write backend
-        "tomli_w",
-    ],
+    hiddenimports=_hiddenimports,
     hookspath=[],
     runtime_hooks=[],
     excludes=[],