split example visualizaiton pipeline

examples/viz/recording.py

@@ -0,0 +1,71 @@
+"""Simple frame recording helper for example scripts."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+import cv2
+
+from .opencv_maps import frame_to_bgr
+
+
+class FrameRecorder:
+    """Write camera frames to disk on demand (start/stop via keyboard hooks)."""
+
+    def __init__(self, save_path: str | Path = "./data/pulse_test.mp4", fps: int = 30) -> None:
+        self.save_path = Path(save_path)
+        self.fps = fps
+        self._writer: cv2.VideoWriter | None = None
+        self._is_recording = False
+        self._frame_count = 0
+
+    @property
+    def is_recording(self) -> bool:
+        return self._is_recording
+
+    def write_if_recording(self, frame) -> None:
+        if not self._is_recording or self._writer is None or frame is None:
+            return
+        self._writer.write(frame_to_bgr(frame))
+        self._frame_count += 1
+
+    def start(self, frame) -> bool:
+        if frame is None:
+            print("当前没有可用帧，无法确定录像尺寸。")
+            return False
+
+        self.save_path.parent.mkdir(parents=True, exist_ok=True)
+        bgr = frame_to_bgr(frame)
+        height, width = bgr.shape[:2]
+        writer = cv2.VideoWriter(
+            str(self.save_path),
+            cv2.VideoWriter_fourcc(*"mp4v"),
+            self.fps,
+            (width, height),
+        )
+        if not writer.isOpened():
+            print(f"无法创建录像文件：{self.save_path}")
+            return False
+
+        self._writer = writer
+        self._is_recording = True
+        self._frame_count = 0
+        print(f"开始录像：{self.save_path}")
+        return True
+
+    def stop(self) -> tuple[Path | None, int]:
+        self._is_recording = False
+        if self._writer is not None:
+            self._writer.release()
+            self._writer = None
+
+        path = self.save_path if self._frame_count else None
+        if path is not None:
+            print(f"录像结束：{path}，总帧数：{self._frame_count}")
+        else:
+            print(f"录像结束，总帧数：{self._frame_count}")
+
+        count = self._frame_count
+        self._frame_count = 0
+        return path, count