What is the Generator Pattern?

A generator is a Python function that pauses execution and yields values incrementally using the yield keyword. It maintains its state between calls, making it ideal for:

• Processing large datasets
• Real-time streams
• Memory-efficient pipelines

Key Components in Your Video Analyzer

How It Works in Your Code

def run_analysis(self):
    """Generator that processes frames on demand"""
    try:
        while self.cap.isOpened():
            # 1. Get frame from video
            ret, frame = self.cap.read()
            if not ret: break

            # 2. Process frame
            processed_frame = self._process_frame(frame)

            # 3. Yield results IMMEDIATELY
            yield {
                'frame': processed_frame,
                'warnings_posture': current_warnings,
                'metrics': current_metrics
            }

    finally:
        # 4. Final cleanup when done
        self._release_resources()
        self._generate_final_plot()

Execution Flow

sequenceDiagram
    participant Caller
    participant Generator
    participant VideoFile

    Caller->>Generator: Start processing
    loop Frame-by-Frame
        Generator->>VideoFile: Get next frame
        VideoFile->>Generator: Return frame
        Generator->>Generator: Process frame
        Generator->>Caller: Yield frame results
        Caller->>Caller: Handle results immediately
    end
    Generator->>Generator: Cleanup resources
    Generator->>Caller: Return final outputs

Example Usage

# Initialize analyzer
analyzer = CPRAnalyzer("cpr_video.mp4")

# Process in real-time
for frame_data in analyzer.run_analysis():
    # Immediate access to frame results
    print(f"Frame {frame_data['frame_number']}")
    print(f"Posture warnings: {frame_data['warnings_posture']}")

    # Optional: Preview processed frame
    cv2.imshow('CPR Analysis', frame_data['frame'])
    cv2.waitKey(1)

# After full processing
print(f"Saved video: {analyzer.output_video_path}")
print(f"Analysis plot: {analyzer.plot_path}")

Key Advantages Over Batch Processing