Implement initial structure and core functionality for Duck Preview application

duck_preview/telemetry/collector.py

@@ -0,0 +1,39 @@
+from __future__ import annotations
+
+import time
+from collections import deque
+
+from PySide6.QtCore import QObject
+from PySide6.QtMultimedia import QVideoFrame
+
+
+class TelemetryCollector(QObject):
+    def __init__(self, parent: QObject | None = None) -> None:
+        super().__init__(parent)
+        self._timestamps: deque[float] = deque(maxlen=500)
+
+    def on_frame(self, frame: QVideoFrame) -> None:
+        self._timestamps.append(time.perf_counter())
+
+    def metrics(self) -> dict[str, float | int]:
+        if not self._timestamps:
+            return {"fps": 0, "frame_time_ms": 0.0, "frame_count": 0}
+
+        now = time.perf_counter()
+        cutoff = now - 1.0
+        recent = [t for t in self._timestamps if t >= cutoff]
+        fps = len(recent)
+
+        frame_time_ms = 0.0
+        if len(self._timestamps) >= 2:
+            diffs = [
+                self._timestamps[i] - self._timestamps[i - 1]
+                for i in range(1, len(self._timestamps))
+            ]
+            frame_time_ms = (sum(diffs) / len(diffs)) * 1000 if diffs else 0.0
+
+        return {
+            "fps": fps,
+            "frame_time_ms": round(frame_time_ms, 2),
+            "frame_count": len(self._timestamps),
+        }