scrub optimization

cht/ui/monitor.py

@@ -51,6 +51,8 @@ class MonitorWidget(Gtk.Box):
         self._live_loaded = False
 
         self._review_player = None
+        self._scrub_offset = 0.0  # global offset of the loaded scrub source
+        self._scrub_active = False  # True when scrub source is loaded
 
         self._stack = Gtk.Stack()
         self._stack.set_hexpand(True)
@@ -87,6 +89,21 @@ class MonitorWidget(Gtk.Box):
         self._recording_path = path
         log.info("Recording path: %s", path)
 
+    def set_scrub_source(self, proxy_path, global_offset=0.0):
+        """Load a proxy file for frame-accurate scrubbing."""
+        self._recording_path = proxy_path
+        self._scrub_offset = global_offset
+        self._scrub_active = True
+        if self._review_player:
+            self._review_player.load_at(proxy_path, 0, pause=True, hr_seek=True)
+        self._stack.set_visible_child_name("review")
+        log.info("Scrub source: %s (offset %.1fs)", proxy_path, global_offset)
+
+    def scrub_to(self, seconds):
+        """Seek the review player to an exact frame (for scrub bar dragging)."""
+        if self._review_player:
+            self._review_player.show_frame_at(seconds)
+
     def get_live_position(self):
         """Return the live player's current time_pos, or None."""
         if self._live_player:
@@ -105,6 +122,8 @@ class MonitorWidget(Gtk.Box):
         self._live_source_url = None
         self._recording_path = None
         self._live_loaded = False
+        self._scrub_active = False
+        self._scrub_offset = 0.0
         if self._live_player:
             self._live_player.command("stop")
         if self._review_player:
@@ -180,6 +199,7 @@ class MonitorWidget(Gtk.Box):
         current = self._stack.get_visible_child_name()
 
         if s.live:
+            self._scrub_active = False
             # Ensure live player is loaded and playing
             if self._live_player and not self._live_loaded and self._live_source_url:
                 self._live_player.load_live(self._live_source_url)
@@ -190,17 +210,22 @@ class MonitorWidget(Gtk.Box):
             if current != "live":
                 self._stack.set_visible_child_name("live")
         else:
-            # Scrub mode
-            if current == "live":
+            # Scrub / review mode
+            if self._scrub_active:
+                # Scrub mode: driven directly by scrub_to(), not by timeline
+                if current != "review":
+                    self._stack.set_visible_child_name("review")
+                return
+            elif current == "live":
                 # Transitioning from live: load MKV at cursor position atomically
-                pos = s.cursor  # already set by toggle_live()
+                pos = s.cursor
                 if self._review_player and self._recording_path:
                     self._review_player.load_at(self._recording_path, pos, pause=s.paused)
                     if not s.paused:
                         self._review_player.play()
                 self._stack.set_visible_child_name("review")
             else:
-                # Already in review: seek if cursor moved, then apply pause/play
+                # Already in review (non-scrub): seek if cursor moved
                 if self._review_player:
                     player_pos = self._review_player.time_pos or 0
                     if abs(s.cursor - player_pos) > 1.0:
@@ -212,9 +237,12 @@ class MonitorWidget(Gtk.Box):
 
     def _sync_cursor_from_player(self):
         s = self._timeline.state
+        if self._scrub_active:
+            # Scrub mode: don't sync cursor from player — scrub bar drives cursor
+            return True
         if not s.live and not s.paused and self._review_player:
             pos = self._review_player.time_pos
             if pos is not None and pos > 0:
                 self._timeline.set_cursor(pos)
-        # Live mode: cursor driven by tick_live() in window.py
+        # Live mode: cursor driven by tick_live()
         return True