jpeg_streaming.py

#!/usr/bin/env python3
"""
JPEG Video Streaming Example

Demonstrates real-time JPEG frame streaming and video recording
with proper resource management using context managers.
"""

import serial
import time
from pydiplink import JpegVideoWriter, receive_and_show_jpeg


def main():
    # Configuration
    PORT = "/dev/ttyUSB0"
    BAUD = 500000
    OUTPUT_VIDEO = "output.avi"
    FPS = 30
    RESOLUTION = (640, 480)
    NUM_FRAMES = 300  # Record 10 seconds at 30 FPS

    print(f"Connecting to {PORT}...")

    try:
        ser = serial.Serial(PORT, BAUD, timeout=5)
        print("Connected!")
        print(f"\nRecording {NUM_FRAMES} frames ({NUM_FRAMES/FPS:.1f} seconds)")
        print(f"Resolution: {RESOLUTION[0]}x{RESOLUTION[1]} at {FPS} FPS")
        print(f"Output: {OUTPUT_VIDEO}\n")

        # Use context manager for automatic cleanup
        with JpegVideoWriter(OUTPUT_VIDEO, fps=FPS, resolution=RESOLUTION) as writer:
            frames_received = 0
            start_time = time.time()

            for i in range(NUM_FRAMES):
                try:
                    # Receive JPEG frame
                    frame = receive_and_show_jpeg(ser, resolution=RESOLUTION)

                    if frame is None:
                        print(f"Frame {i+1}: failed to receive, skipping...")
                        continue

                    writer.write_frame(frame)
                    frames_received += 1

                    # Progress indicator
                    if (i + 1) % 30 == 0:
                        elapsed = time.time() - start_time
                        fps_actual = frames_received / elapsed
                        print(
                            f"Frame {i+1}/{NUM_FRAMES} "
                            f"({fps_actual:.1f} FPS, {elapsed:.1f}s elapsed)"
                        )

                except TimeoutError:
                    print(f"Frame {i+1}: timeout, skipping...")
                    continue

                except KeyboardInterrupt:
                    print("\nInterrupted by user")
                    break

                except Exception as e:
                    print(f"Frame {i+1}: error - {e}")
                    continue

        # Video writer automatically closed by context manager

        elapsed_total = time.time() - start_time
        avg_fps = frames_received / elapsed_total

        print(f"\n=== Recording Complete ===")
        print(f"Frames received: {frames_received}/{NUM_FRAMES}")
        print(f"Total time: {elapsed_total:.1f}s")
        print(f"Average FPS: {avg_fps:.1f}")
        print(f"Video saved to: {OUTPUT_VIDEO}")

    except serial.SerialException as e:
        print(f"Serial error: {e}")

    except KeyboardInterrupt:
        print("\nRecording interrupted by user")

    finally:
        if 'ser' in locals():
            ser.close()
            print("Serial port closed")


if __name__ == "__main__":
    main()