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Python屏幕捕获错误(Python screen capture error)

 我正在尝试修改这里给出的用于屏幕流的代码。 在上面的教程中，它用于从磁盘读取图像，而我试图截取屏幕截图。 我收到此错误。  
 
  断言isinstance（数据，字节）'应用程序必须写入字节'AssertionError：应用程序必须写入字节  
 
 我应该做些什么改变才能发挥作用？  
 这就是我迄今为止所做的 -  
<br>index.html<br>
<html>
  <head>
    <title>Video Streaming Demonstration</title>
  </head>
  <body>
    <h1>Video Streaming Demonstration</h1>
    <img src="{{ url_for('video_feed') }}">
  </body>
</html>
 

 app.py 
 
#!/usr/bin/env python
from flask import Flask, render_template, Response
import time
# emulated camera
from camera import Camera

# Raspberry Pi camera module (requires picamera package)
# from camera_pi import Camera

app = Flask(__name__)


@app.route('/')
def index():
    """Video streaming home page."""
    return render_template('index.html')


def gen(camera):
    """Video streaming generator function."""
    while True:
        time.sleep(0.1)
        frame = camera.get_frame()
        yield (frame)


@app.route('/video_feed')
def video_feed():
    """Video streaming route. Put this in the src attribute of an img tag."""
    return Response(gen(Camera()),
                    mimetype='multipart/x-mixed-replace; boundary=frame')


if __name__ == '__main__':
    app.run(host='0.0.0.0', debug=True, threaded=True)
 

 camera.py 
 
from time import time

from PIL import Image
from PIL import ImageGrab
import sys

if sys.platform == "win32":
    grabber = Image.core.grabscreen

class Camera(object):

    def __init__(self):
        #self.frames = [open('shot0' + str(f) + '.png', 'rb').read() for f in range(1,61)]
        self.frames = [ImageGrab.grab() for f in range(1,61)]

    def get_frame(self):
        return self.frames[int(time()) % 3]
 
 完整的错误： 链接 

I am trying to modify the code given here for screen streaming. In the above tutorial it was for reading images from disk whereas I am trying to take screenshots. I receive this error. 
 
 assert isinstance(data, bytes), 'applications must write bytes' AssertionError: applications must write bytes 
 
What changes should I make for it to work? 
This is what I've done so far -  
<br>index.html<br>
<html>
  <head>
    <title>Video Streaming Demonstration</title>
  </head>
  <body>
    <h1>Video Streaming Demonstration</h1>
    <img src="{{ url_for('video_feed') }}">
  </body>
</html>
 

app.py
 
#!/usr/bin/env python
from flask import Flask, render_template, Response
import time
# emulated camera
from camera import Camera

# Raspberry Pi camera module (requires picamera package)
# from camera_pi import Camera

app = Flask(__name__)


@app.route('/')
def index():
    """Video streaming home page."""
    return render_template('index.html')


def gen(camera):
    """Video streaming generator function."""
    while True:
        time.sleep(0.1)
        frame = camera.get_frame()
        yield (frame)


@app.route('/video_feed')
def video_feed():
    """Video streaming route. Put this in the src attribute of an img tag."""
    return Response(gen(Camera()),
                    mimetype='multipart/x-mixed-replace; boundary=frame')


if __name__ == '__main__':
    app.run(host='0.0.0.0', debug=True, threaded=True)
 

camera.py
 
from time import time

from PIL import Image
from PIL import ImageGrab
import sys

if sys.platform == "win32":
    grabber = Image.core.grabscreen

class Camera(object):

    def __init__(self):
        #self.frames = [open('shot0' + str(f) + '.png', 'rb').read() for f in range(1,61)]
        self.frames = [ImageGrab.grab() for f in range(1,61)]

    def get_frame(self):
        return self.frames[int(time()) % 3]
 
Full error : Link

原文：https://stackoverflow.com/questions/40060653

更新时间：2024-04-25 09:04

最满意答案

 尝试使用UnmanagedMemoryStream ：  
 
  此类支持使用现有的基于流的模型访问非托管内存，并且不要求将非托管内存中的内容复制到堆中。  
 
 这意味着您将寻找/读取/重置流，但这避免了编组。 它仍然不是你希望在.NET属性中包含这些访问的意义上的。  
 另一种选择：也许你可以在获得非托管指针后使用System.Buffer 。 你可能需要做一些聪明的演员。 

Try using the UnmanagedMemoryStream: 
 
 This class supports access to unmanaged memory using the existing stream-based model and does not require that the contents in the unmanaged memory be copied to the heap. 
 
This means you will be seeking/reading/resetting the stream, but this avoids the marshalling. It's still not live in the sense you'd want to probably want to wrap these accesses in .NET properties. 
Another alternative: maybe you could use System.Buffer, after getting the unmanaged pointer. You may need to do some clever casting.

Python屏幕捕获错误(Python screen capture error)

最满意答案

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