NodeJS 对Python编码的视频帧进行解码，以在基于节点的Web应用程序中显示

6tqwzwtp 于 2022-11-04 发布在 Node.js

关注(0)|答案(1)|浏览(111)

我使用Python 3和OpenCV来读取视频，并通过套接字将帧发送到基于Node.js的网页。
让我们想象一下这样的情况：

cap = cv2.VideoCapture(video_path)
while cap.isOpened():
    ret, frame = cap.read()
    send(frame)

在send()函数中，在实际发送之前，我将帧传递给normalize()函数，将其转换为套接字IO可交付的格式。normalize()如下所示：

def normalize(frame):
    d = frame.flatten()
    s = d.tostring()
    b = b64encode(s)
    return b.decode('ascii')

在Node.js应用程序中，我收到了如下信息：

如何将此编码字符串转换为普通视频，甚至图像？

谢谢-谢谢

node.js

来源：https://stackoverflow.com/questions/51130490/decode-video-frame-encoded-by-python-to-display-in-node-based-webapp

1条答案

按热度按时间

xmq68pz91#

要对图像进行编码，请使用cv2.imencode()。然后，您可以将该缓冲区写入一个base 64字符串，然后直接用HTML显示该缓冲区，或者对它执行任何您希望的操作。
下面是一个基本的例子。首先，Python：

import cv2
import base64

def encode_img(img):
    """Encodes an image as a png and encodes to base 64 for display."""
    success, encoded_img = cv2.imencode('.png', img)
    if success:
        return base64.b64encode(encoded_img).decode()
    raise ValueError("unable to encode image")

这将给予base 64格式的编码图像。如果将data:image/png;base64,添加到该字符串前面，则可以将该字符串用作图像的src，从而直接使用HTML显示该字符串返回的图像。
比如说...

import numpy as np
img = np.uint8(255 * np.random.rand(50, 50))
encoded_img = encode_img(img)
b64_src = 'data:image/png;base64,'
img_src = b64_src + encoded_img

有了这个随机的图像，我的img_src变成：

'data:image/png;base64,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'

然后在一个简单的HTML文件中，使用以下代码作为图像标记的源代码：

<html>
<body>
    <img src="data:image/png;base64,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">
</body>
</html>

你应该能看到图像。
您也可以使用此格式将它们直接保存为节点服务器上的影像。例如，您可以使用{encoding: 'base64'}指定选项对象，将此b64字串直接写入影像档。例如，从this tutorial：

import fs from 'fs';
fs.writeFile('image.png', base64Image, {encoding: 'base64'}, function(err) {
    console.log('File created');
});

当然，如果你使用节点中的其他库来处理图像，你需要使用该库中的一些函数来解码图像。从b64转换为bytes可能并不太难，但是你需要将这些bytes解码为你在服务器端使用的任何库中的图像。

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NodeJS 对Python编码的视频帧进行解码，以在基于节点的Web应用程序中显示

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