Python视频流新手初始化摄像头错误

Question

我想在我的树莓派USB摄像头和我的笔记本电脑之间建立一个视频流。

客户端：

import io
import socket
import struct
import time
import pygame.camera

# Connect a client socket to my_server:8000 (change my_server to the
# hostname of your server)
client_socket = socket.socket()
client_socket.connect(('192.168.1.12', 8000))

# Make a file-like object out of the connection
connection = client_socket.makefile('wb')
try:
    with pygame.camera.Camera ()as camera:
        camera.resolution = (640, 480)
        # Start a preview and let the camera warm up for 2 seconds
        camera.start_preview()
        time.sleep(2)

        # Note the start time and construct a stream to hold image data
        # temporarily (we could write it directly to connection but in this
        # case we want to find out the size of each capture first to keep
        # our protocol simple)
        start = time.time()
        stream = io.BytesIO()
        for foo in camera.capture_continuous(stream, 'jpeg'):
            # Write the length of the capture to the stream and flush to
            # ensure it actually gets sent
            connection.write(struct.pack('<L', stream.tell()))
            connection.flush()
            # Rewind the stream and send the image data over the wire
            stream.seek(0)
            connection.write(stream.read())
            # If we've been capturing for more than 30 seconds, quit
            if time.time() - start > 30:
                break
            # Reset the stream for the next capture
            stream.seek(0)
            stream.truncate()
    # Write a length of zero to the stream to signal we're done
    connection.write(struct.pack('<L', 0))
finally:
    connection.close()
    client_socket.close()

但是我遇到了这个问题：

错误信息：`追踪（最近的调用最后）：

  File "camera.py", line 15, in <module> with pygame.camera.Camera ()as camera:
  File "/usr/lib/python2.7/dist-packages/pygame/camera.py", line 100, in __init__
    _check_init()
  File "/usr/lib/python2.7/dist-packages/pygame/camera.py", line 86, in _check_init raise     ValueError("Need to call camera.init() before using.")
  ValueError: Need to call camera.init() before using.

我对这个编程语言还很陌生，所以我不知道怎么初始化摄像头来使用它。我在网上找到了一些教程，但还是没搞清楚我代码中的错误部分。

Answer 1

这个问题发生是因为你在调用 Camera() 之前没有初始化 pygame。

首先，确保你导入了所有需要的内容：

import pygame
import pygame.camera
from pygame.locals import *

接下来，你需要初始化 pygame 和 pygame.camera：

pygame.init()
pygame.camera.init()

最后，像之前一样创建 Camera 对象：

with pygame.camera.Camera ()as camera:
   blablabla...