用于在python中通过tcp套接字传输视频的代码；需要帮助理解其中的一部分。

# 服务器端代码
import socket
import cv2

# 创建TCP套接字
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 绑定IP和端口
server_address = ('localhost', 8000)
server_socket.bind(server_address)

# 监听连接
server_socket.listen(1)
print('等待客户端连接...')

# 接受客户端连接
client_socket, client_address = server_socket.accept()
print('客户端已连接:', client_address)

# 读取视频文件
video_file = 'video.mp4'
video_capture = cv2.VideoCapture(video_file)

# 循环发送视频帧
while True:
    ret, frame = video_capture.read()
    if not ret:
        break

    # 将视频帧转换为字节流
    _, encoded_frame = cv2.imencode('.jpg', frame)
    frame_data = encoded_frame.tobytes()

    # 发送视频帧大小
    frame_size = len(frame_data)
    frame_size_bytes = frame_size.to_bytes(4, byteorder='big')
    client_socket.send(frame_size_bytes)

    # 发送视频帧数据
    client_socket.sendall(frame_data)

# 关闭连接
video_capture.release()
client_socket.close()
server_socket.close()
print('传输完成，连接已关闭。')


# 客户端代码
import socket
import cv2
import numpy as np

# 创建TCP套接字
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 服务器地址
server_address = ('localhost', 8000)

# 连接服务器
client_socket.connect(server_address)
print('已连接到服务器:', server_address)

# 创建窗口
cv2.namedWindow('Video', cv2.WINDOW_NORMAL)

# 接收并显示视频帧
while True:
    # 接收视频帧大小
    frame_size_bytes = client_socket.recv(4)
    frame_size = int.from_bytes(frame_size_bytes, byteorder='big')

    # 接收视频帧数据
    frame_data = b''
    while len(frame_data) < frame_size:
        data = client_socket.recv(frame_size - len(frame_data))
        frame_data += data

    # 将接收到的视频帧数据解码为图像
    frame = cv2.imdecode(np.frombuffer(frame_data, dtype=np.uint8), cv2.IMREAD_COLOR)

    # 显示视频帧
    cv2.imshow('Video', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# 关闭连接
client_socket.close()
cv2.destroyAllWindows()
print('连接已关闭。')