refactor: enhance FFmpegRTSPReader with file watching and reactive frame reading

.claude/settings.local.json

@@ -1,7 +1,8 @@
 {
   "permissions": {
     "allow": [
-      "Bash(dir:*)"
+      "Bash(dir:*)",
+      "WebSearch"
     ],
     "deny": [],
     "ask": []

core/streaming/readers.py

@@ -11,6 +11,8 @@ import numpy as np
 import os
 import subprocess
 from typing import Optional, Callable
+from watchdog.observers import Observer
+from watchdog.events import FileSystemEventHandler
 
 # Suppress FFMPEG/H.264 error messages if needed
 # Set this environment variable to reduce noise from decoder errors
@@ -20,8 +22,25 @@ os.environ["OPENCV_FFMPEG_LOGLEVEL"] = "-8"  # Suppress FFMPEG warnings
 logger = logging.getLogger(__name__)
 
 
+class FrameFileHandler(FileSystemEventHandler):
+    """File system event handler for frame file changes."""
+
+    def __init__(self, callback):
+        self.callback = callback
+        self.last_modified = 0
+
+    def on_modified(self, event):
+        if event.is_directory:
+            return
+        # Debounce rapid file changes
+        current_time = time.time()
+        if current_time - self.last_modified > 0.01:  # 10ms debounce
+            self.last_modified = current_time
+            self.callback()
+
+
 class FFmpegRTSPReader:
-    """RTSP stream reader using subprocess FFmpeg with CUDA hardware acceleration."""
+    """RTSP stream reader using subprocess FFmpeg with CUDA hardware acceleration and file watching."""
 
     def __init__(self, camera_id: str, rtsp_url: str, max_retries: int = 3):
         self.camera_id = camera_id
@@ -31,6 +50,8 @@ class FFmpegRTSPReader:
         self.stop_event = threading.Event()
         self.thread = None
         self.frame_callback: Optional[Callable] = None
+        self.observer = None
+        self.frame_ready_event = threading.Event()
 
         # Stream specs
         self.width = 1280
@@ -67,7 +88,6 @@ class FFmpegRTSPReader:
     def _start_ffmpeg_process(self):
         """Start FFmpeg subprocess with CUDA hardware acceleration writing to temp file."""
         # Create temp file path for this camera
-        import tempfile
         self.temp_file = f"/tmp/claude/camera_{self.camera_id.replace(' ', '_')}.raw"
         os.makedirs("/tmp/claude", exist_ok=True)
 
@@ -85,114 +105,113 @@ class FFmpegRTSPReader:
         ]
 
         try:
+            # Start FFmpeg detached - we don't need to communicate with it
             self.process = subprocess.Popen(
                 cmd,
-                stdout=subprocess.PIPE,
-                stderr=subprocess.PIPE,
-                bufsize=0
+                stdout=subprocess.DEVNULL,
+                stderr=subprocess.DEVNULL
             )
-            logger.info(f"Started FFmpeg process for camera {self.camera_id} writing to {self.temp_file}")
-
-            # Don't check process immediately - FFmpeg takes time to initialize
-            logger.info(f"Waiting for FFmpeg to initialize for camera {self.camera_id}...")
+            logger.info(f"Started FFmpeg process PID {self.process.pid} for camera {self.camera_id} -> {self.temp_file}")
             return True
         except Exception as e:
             logger.error(f"Failed to start FFmpeg for camera {self.camera_id}: {e}")
             return False
 
+    def _setup_file_watcher(self):
+        """Setup file system watcher for temp file."""
+        if not os.path.exists(self.temp_file):
+            return
+
+        # Setup file watcher
+        handler = FrameFileHandler(self._on_file_changed)
+        self.observer = Observer()
+        self.observer.schedule(handler, os.path.dirname(self.temp_file), recursive=False)
+        self.observer.start()
+        logger.info(f"Started file watcher for {self.temp_file}")
+
+    def _on_file_changed(self):
+        """Called when temp file is modified."""
+        if os.path.basename(self.temp_file) in str(self.temp_file):
+            self.frame_ready_event.set()
+
     def _read_frames(self):
-        """Read frames from FFmpeg temp file."""
-        consecutive_errors = 0
+        """Reactively read frames when file changes."""
         frame_count = 0
         last_log_time = time.time()
-        bytes_per_frame = self.width * self.height * 3  # BGR = 3 bytes per pixel
-        last_file_size = 0
+        bytes_per_frame = self.width * self.height * 3
+        restart_check_interval = 10  # Check FFmpeg status every 10 seconds
 
         while not self.stop_event.is_set():
             try:
-                # Start/restart FFmpeg process if needed
+                # Start FFmpeg if not running
                 if not self.process or self.process.poll() is not None:
+                    if self.process and self.process.poll() is not None:
+                        logger.warning(f"FFmpeg process died for camera {self.camera_id}, restarting...")
+
                     if not self._start_ffmpeg_process():
                         time.sleep(5.0)
                         continue
 
-                # Wait for temp file to exist and have content
-                if not os.path.exists(self.temp_file):
-                    time.sleep(0.1)
-                    continue
+                    # Wait for temp file to be created
+                    wait_count = 0
+                    while not os.path.exists(self.temp_file) and wait_count < 30:
+                        time.sleep(1.0)
+                        wait_count += 1
 
-                # Check if file size changed (new frame available)
-                try:
-                    current_file_size = os.path.getsize(self.temp_file)
-                    if current_file_size <= last_file_size and current_file_size > 0:
-                        # File size didn't increase, wait for next frame
-                        time.sleep(0.05)  # ~20 FPS max
-                        continue
-                    last_file_size = current_file_size
-                except OSError:
-                    time.sleep(0.1)
-                    continue
-
-                # Read the latest frame from the end of file
-                try:
-                    with open(self.temp_file, 'rb') as f:
-                        # Seek to last complete frame
-                        file_size = f.seek(0, 2)  # Seek to end
-                        if file_size < bytes_per_frame:
-                            time.sleep(0.1)
-                            continue
-
-                        # Read last complete frame
-                        last_frame_offset = (file_size // bytes_per_frame - 1) * bytes_per_frame
-                        f.seek(last_frame_offset)
-                        frame_data = f.read(bytes_per_frame)
-
-                    if len(frame_data) != bytes_per_frame:
-                        consecutive_errors += 1
-                        if consecutive_errors >= 30:
-                            logger.error(f"Camera {self.camera_id}: Too many read errors, restarting FFmpeg")
-                            if self.process:
-                                self.process.terminate()
-                            consecutive_errors = 0
-                        time.sleep(0.1)
+                    if not os.path.exists(self.temp_file):
+                        logger.error(f"Temp file not created after 30s for {self.camera_id}")
                         continue
 
-                    # Convert raw bytes to numpy array
-                    frame = np.frombuffer(frame_data, dtype=np.uint8)
-                    frame = frame.reshape((self.height, self.width, 3))
+                    # Setup file watcher
+                    self._setup_file_watcher()
 
-                    # Frame is valid
-                    consecutive_errors = 0
-                    frame_count += 1
+                # Wait for file change event (or timeout for health check)
+                if self.frame_ready_event.wait(timeout=restart_check_interval):
+                    self.frame_ready_event.clear()
 
-                    # Call frame callback
-                    if self.frame_callback:
-                        try:
-                            self.frame_callback(self.camera_id, frame)
-                        except Exception as e:
-                            logger.error(f"Camera {self.camera_id}: Frame callback error: {e}")
+                    # Read latest frame
+                    try:
+                        with open(self.temp_file, 'rb') as f:
+                            # Get file size
+                            f.seek(0, 2)
+                            file_size = f.tell()
 
-                    # Log progress
-                    current_time = time.time()
-                    if current_time - last_log_time >= 30:
-                        logger.info(f"Camera {self.camera_id}: {frame_count} frames processed via temp file")
-                        last_log_time = current_time
+                            if file_size < bytes_per_frame:
+                                continue
 
-                except IOError as e:
-                    logger.debug(f"Camera {self.camera_id}: File read error: {e}")
-                    time.sleep(0.1)
-                    continue
+                            # Read last complete frame
+                            last_frame_offset = (file_size // bytes_per_frame - 1) * bytes_per_frame
+                            f.seek(last_frame_offset)
+                            frame_data = f.read(bytes_per_frame)
+
+                            if len(frame_data) == bytes_per_frame:
+                                # Convert to numpy array
+                                frame = np.frombuffer(frame_data, dtype=np.uint8)
+                                frame = frame.reshape((self.height, self.width, 3))
+
+                                # Call frame callback
+                                if self.frame_callback:
+                                    self.frame_callback(self.camera_id, frame)
+
+                                frame_count += 1
+
+                                # Log progress
+                                current_time = time.time()
+                                if current_time - last_log_time >= 30:
+                                    logger.info(f"Camera {self.camera_id}: {frame_count} frames processed reactively")
+                                    last_log_time = current_time
+
+                    except (IOError, OSError) as e:
+                        logger.debug(f"Camera {self.camera_id}: File read error: {e}")
 
             except Exception as e:
-                logger.error(f"Camera {self.camera_id}: FFmpeg read error: {e}")
-                consecutive_errors += 1
-                if consecutive_errors >= 30:
-                    if self.process:
-                        self.process.terminate()
-                    consecutive_errors = 0
+                logger.error(f"Camera {self.camera_id}: Error in reactive frame reading: {e}")
                 time.sleep(1.0)
 
         # Cleanup
+        if self.observer:
+            self.observer.stop()
+            self.observer.join()
         if self.process:
             self.process.terminate()
         # Clean up temp file
@@ -201,7 +220,7 @@ class FFmpegRTSPReader:
                 os.remove(self.temp_file)
         except:
             pass
-        logger.info(f"FFmpeg reader thread ended for camera {self.camera_id}")
+        logger.info(f"Reactive FFmpeg reader ended for camera {self.camera_id}")
 
 
 logger = logging.getLogger(__name__)