picam_client.py

# Much of the code from: https://picamera.readthedocs.io/en/release-1.13/recipes2.html
# Run this on your RaspberryPi.

import time
import io
import struct
import picamera
import socket
import os

class SplitFrames(object):
    def __init__(self, connection):
        self.connection = connection
        self.stream = io.BytesIO()
        self.count = 0

    def write(self, buf):
        if buf.startswith(b'\xff\xd8'):
            # Start of new frame; send the old one's length
            # then the data
            size = self.stream.tell()
            if size > 0:
                self.connection.write(struct.pack('<L', size))
                self.connection.flush()
                self.stream.seek(0)
                self.connection.write(self.stream.read(size))
                self.count += 1
                self.stream.seek(0)
        self.stream.write(buf)

PORT = os.getenv('PICAM_PORT', 5190)
HOST = os.getenv('PICAM_HOST', None)
assert HOST is not None
client_socket = socket.socket()
client_socket.connect((HOST, PORT))
connection = client_socket.makefile('wb')

try:
    output = SplitFrames(connection)
    with picamera.PiCamera(resolution='VGA', framerate=30) as camera:
        time.sleep(2)
        start = time.time()
        camera.start_recording(output, format='mjpeg')
        camera.wait_recording(30)
        camera.stop_recording()
        # Write the terminating 0-length to the connection to let the
        # server know we're done
        connection.write(struct.pack('<L', 0))
finally:
    connection.close()
    client_socket.close()
    finish = time.time()
print('Sent %d images in %d seconds at %.2ffps' % (
    output.count, finish-start, output.count / (finish-start)))