在python中从jpeg图像创建一个mjpeg流 [英] Create a mjpeg stream from jpeg images in python

问题描述

我需要提供实时图表，我想通过http传递一个mjpeg流（因此很容易通过使用普通标记将图表包含在网页中）。

I need to serve real-time graphs and I would like to deliver a mjpeg stream over http (so that it is easy to include the graphs in a web-page by using a plain tag).

是否可以实时从多个jpeg图像创建mjpeg流？

Is it possible to create an mjpeg stream from multiple jpeg images, in realtime ?

我的策略是：

1. 输出正确的http标头：

1. Output the correct http headers:

Cache-Control:no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0
Connection:close
Content-Type:multipart/x-mixed-replace;boundary=boundarydonotcross
Expires:Mon, 3 Jan 2000 12:34:56 GMT
Pragma:no-cache
Server:MJPG-Streamer/0.2

（从 curl -I {在mjpeg-streamer实例上获得} ，但这看起来很奇怪）

(got it from a curl -I {on a mjpeg-streamer instance}, but this seems strange)

简单地生成连续的jp​​eg图像二进制文件，注意：

Simply yield the successive jpeg images binaries, taking care to:

• 在流的开头添加正确的标题（如mjpeg-streamer那样）：

• prepend the correct headers at the beginning of the stream (as mjpeg-streamer does):

Content-Type: image/jpeg
Content-Length: 5427
X-Timestamp: 3927662.086099

在每个jpeg流的末尾附加边界字符串。

append the boundary string at the end of each jpeg streams.

--boudary--

---

问题：

你做过吗，

你知道一个python模块吗？

do you know a python module that does that,

你觉得它会起作用，

你有什么建议吗？

推荐答案

我认为它是一个概念验证： https://github.com/ damiencorpataux / pymjpeg

I got it working as a proof-of-concept: https://github.com/damiencorpataux/pymjpeg

对于记忆：

import os, time
from glob import glob
import sys
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler

boundary = '--boundarydonotcross'

def request_headers():
    return {
        'Cache-Control': 'no-store, no-cache, must-revalidate, pre-check=0, post-check=0, max-age=0',
        'Connection': 'close',
        'Content-Type': 'multipart/x-mixed-replace;boundary=%s' % boundary,
        'Expires': 'Mon, 3 Jan 2000 12:34:56 GMT',
        'Pragma': 'no-cache',
    }

def image_headers(filename):
    return {
        'X-Timestamp': time.time(),
        'Content-Length': os.path.getsize(filename),
        #FIXME: mime-type must be set according file content
        'Content-Type': 'image/jpeg',
    }

# FIXME: should take a binary stream
def image(filename):
    with open(filename, "rb") as f:
        # for byte in f.read(1) while/if byte ?
        byte = f.read(1)
        while byte:
            yield byte
            # Next byte
            byte = f.read(1)

# Basic HTTP server
class MyHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        self.send_response(200)
        # Response headers (multipart)
        for k, v in pymjpeg.request_headers().items():
            self.send_header(k, v) 
        # Multipart content
        for filename in glob('img/*'):
            # Part boundary string
            self.end_headers()
            self.wfile.write(pymjpeg.boundary)
            self.end_headers()
            # Part headers
            for k, v in pymjpeg.image_headers(filename).items():
                self.send_header(k, v) 
            self.end_headers()
            # Part binary
            for chunk in pymjpeg.image(filename):
                self.wfile.write(chunk)
    def log_message(self, format, *args):
        return

httpd = HTTPServer(('', 8001), MyHandler)
httpd.serve_forever()

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