如何将视频流从 python 传输到电子？答案

【问题标题】：How to transfer video stream from python to electron?如何将视频流从 python 传输到电子？
【发布时间】：2020-04-11 02:01:58
【问题描述】：

假设我有一个用 python 编写的代码，在循环中我从流视频中获取帧！如何将这些帧实时传输到编写在 electron.js 上的图形界面？

【问题讨论】：

标签： python node.js electron

【解决方案1】：

See available implementations.

【讨论】：

【解决方案2】：

您可以创建一个 Flask 服务器并将所有帧直接传递到 html 页面。然后从您的电子代码调用服务器以显示流程。

webstreaming.py（你的 Flask 服务器）：

# initialize video capture object to read video from external webcam
video_capture = cv2.VideoCapture(1)
# if there is no external camera then take the built-in camera
if not video_capture.read()[0]:
    video_capture = cv2.VideoCapture(0)


# initialize a flask object
app = Flask(__name__)


@app.route("/")
def index():
    # return the rendered template
    return render_template("index.html")


def analyze():
    # grab global references to the video stream, output frame, and
    # lock variables
    global video_capture, outputFrame, lock, status

    while(video_capture.isOpened()):
        # read video frame by frame
        ret, frame = video_capture.read()

        frame = cv2.flip(frame, 1)

        
        # acquire the lock, set the output frame, and release the
        # lock
        with lock:
            outputFrame = frame.copy()

def generate():
    # grab global references to the output frame and lock variables
    global outputFrame, lock
    # loop over frames from the output stream
    while True:
        # wait until the lock is acquired
        with lock:
            # check if the output frame is available, otherwise skip
            # the iteration of the loop
            if outputFrame is None:
                continue
            # encode the frame in JPEG format
            (flag, encodedImage) = cv2.imencode(".jpg", outputFrame)
            # ensure the frame was successfully encoded
            if not flag:
                continue
        # yield the output frame in the byte format
        yield(b'--frame\r\n' b'Content-Type: image/jpeg\r\n\r\n' + 
            bytearray(encodedImage) + b'\r\n')

#This route accepts request against the url http://domain_name/change_label
#You could add the argument, method=["POST"],<br>So the route only accepts post request against that url.
@app.route("/get_label")
def change_label():
    global status, lock
    
    with lock:
        return status

@app.route("/video_feed")
def video_feed():
    # return the response generated along with the specific media
    # type (mime type)
    return Response(generate(),
        mimetype="multipart/x-mixed-replace; boundary=frame")


if __name__ == "__main__":
    # start a thread that will perform motion detection
    t = threading.Thread(target=analyze)
    t.daemon = True
    t.start()
    # start the flask app
    app.run(host="0.0.0.0", port=8000, debug=True, threaded=True, use_reloader=False)

# release the video stream pointer
video_capture.release()

然后在你的 index.html 中（在 templates.html 中）

<html>

<head>
    <title>Video Streaming Demonstration</title>
</head>

<body>
    <h1>Video Streaming Demonstration</h1>
    <img src="{{ url_for('video_feed') }}">
    
</body>

</html>

在你的 main.js 中

const {app, BrowserWindow} = require('electron')

function createWindow () {
    window = new BrowserWindow({width: 800, height: 600})
    window.loadFile('index.html')
}

app.on('ready', createWindow)

app.on('window-all-closed', () => {
    if (process.platform !== 'darwin') {
      app.quit()
    }
})

重要提示：您应该添加将您重定向到模板/index.html 的 index.html（不要混淆这是 2 个不同的文件）。

你还需要预先启动服务器，例如使用并发包和electron-forge。

【讨论】：