Implement initial structure and core functionality for Duck Preview application

duck_preview/dispatcher/frame_dispatcher.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from collections.abc import Callable
+
+from PySide6.QtCore import QObject
+from PySide6.QtMultimedia import QVideoFrame
+
+
+class FrameDispatcher(QObject):
+    def __init__(self, parent: QObject | None = None) -> None:
+        super().__init__(parent)
+        self._subscribers: list[Callable[[QVideoFrame], None]] = []
+
+    def subscribe(self, callback: Callable[[QVideoFrame], None]) -> None:
+        self._subscribers.append(callback)
+
+    def unsubscribe(self, callback: Callable[[QVideoFrame], None]) -> None:
+        self._subscribers.remove(callback)
+
+    def on_frame(self, frame: QVideoFrame) -> None:
+        for cb in self._subscribers:
+            cb(frame)