I am trying to write my own motion detection camera Python program for my Raspberry Pi for recording video when motion is detected. I have the following code using Python Picamera2:
#!/usr/bin/python3
import time, os
from datetime import datetime
import numpy as np
from picamera2 import Picamera2
from picamera2.encoders import H264Encoder
from picamera2.outputs import CircularOutput
time_format = "%Y-%m-%d-%H-%M-%S"
frame_rate = 30
lsize = (320, 240)
picam2 = Picamera2()
video_config = picam2.create_video_configuration(main={"size": (1920, 1080), "format": "RGB888"}, lores={
"size": lsize, "format": "YUV420"})
picam2.configure(video_config)
picam2.start_preview()
encoder = H264Encoder(2000000, repeat=True)
encoder.output = CircularOutput()
picam2.encoder = encoder
picam2.start()
picam2.start_encoder()
w, h = lsize
prev = None
encoding = False
ltime = 0
while True:
cur = picam2.capture_buffer("lores")
cur = cur[:w * h].reshape(h, w)
if prev is not None:
# Measure pixels differences between current and
# previous frame
mse = np.square(np.subtract(cur, prev)).mean()
if mse > 7:
if not encoding:
filename = datetime.now().strftime(time_format)
encoder.output.fileoutput = f"{filename}.h264"
encoder.output.start()
encoding = True
print("New Motion", mse)
ltime = time.time()
else:
if encoding and time.time() - ltime > 5.0:
encoder.output.stop()
encoding = False
time.sleep(1)
os.system(f"ffmpeg -r {frame_rate} -i {filename}.h264 -vcodec copy {filename}.mp4")
os.system(f"rm {filename}.h264")
prev = cur
picam2.stop_encoder()
This does appear to work okay. I had to add the os.system ffmpeg command to convert the video to mp4 so I could actually view the video on my Windows 10 PC.
There are a couple of issues with this:
- I would like to reduce the frame rate to around 15 FPS as the default 30 FPS is not required.
- The focus in the image is not on the centre of the image, but on a shelf that is closer and makes the image very blurry. How can I make it focus on the centre of the image?
- Can I have the encoder output as mp4 or mkv without having to use ffmpeg to convert?
My Raspberry Pi 4 4GB has 22-09-2022 Bullseye OS and is fully up to date. My camera is the new Pi Camera 3 Module.
