Create A Mjpeg Stream From Jpeg Images In Python

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). Is it possible

Solution 1:

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

For memory:

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

boundary = '--boundarydonotcross'defrequest_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',
    }

defimage_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 streamdefimage(filename):
    withopen(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 serverclassMyHandler(BaseHTTPRequestHandler):
    defdo_GET(self):
        self.send_response(200)
        # Response headers (multipart)for k, v in pymjpeg.request_headers().items():
            self.send_header(k, v) 
        # Multipart contentfor filename in glob('img/*'):
            # Part boundary string
            self.end_headers()
            self.wfile.write(pymjpeg.boundary)
            self.end_headers()
            # Part headersfor k, v in pymjpeg.image_headers(filename).items():
                self.send_header(k, v) 
            self.end_headers()
            # Part binaryfor chunk in pymjpeg.image(filename):
                self.wfile.write(chunk)
    deflog_message(self, format, *args):
        return

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

Solution 2:

You may use Flask framework to do this. It is not only for mjpeg. I adapted some code from here: https://blog.miguelgrinberg.com/post/video-streaming-with-flask

APP.py

#!/usr/bin/env pythonfrom importlib import import_module
import os
from flask import Flask, render_template, Response

# import camera driverif os.environ.get('CAMERA'):
    Camera = import_module('camera_' + os.environ['CAMERA']).Camera
else:
    from camera import Camera

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

app = Flask(__name__)


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


defgen(camera):
    """Video streaming generator function."""whileTrue:
        frame = camera.get_frame()
        yield (b'--frame\r\n'b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')


@app.route('/video_feed')defvideo_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', threaded=True)

base_camera.py

import time
import threading
try:
    from greenlet import getcurrent as get_ident
except ImportError:
    try:
        from thread import get_ident
    except ImportError:
        from _thread import get_ident


classCameraEvent(object):
    """An Event-like class that signals all active clients when a new frame is
    available.
    """def__init__(self):
        self.events = {}

    defwait(self):
        """Invoked from each client's thread to wait for the next frame."""
        ident = get_ident()
        if ident notin self.events:
            # this is a new client# add an entry for it in the self.events dict# each entry has two elements, a threading.Event() and a timestamp
            self.events[ident] = [threading.Event(), time.time()]
        return self.events[ident][0].wait()

    defset(self):
        """Invoked by the camera thread when a new frame is available."""
        now = time.time()
        remove = Nonefor ident, event in self.events.items():
            ifnot event[0].isSet():
                # if this client's event is not set, then set it# also update the last set timestamp to now
                event[0].set()
                event[1] = now
            else:
                # if the client's event is already set, it means the client# did not process a previous frame# if the event stays set for more than 5 seconds, then assume# the client is gone and remove itif now - event[1] > 5:
                    remove = ident
        if remove:
            del self.events[remove]

    defclear(self):
        """Invoked from each client's thread after a frame was processed."""
        self.events[get_ident()][0].clear()


classBaseCamera(object):
    thread = None# background thread that reads frames from camera
    frame = None# current frame is stored here by background thread
    last_access = 0# time of last client access to the camera
    event = CameraEvent()

    def__init__(self):
        """Start the background camera thread if it isn't running yet."""if BaseCamera.thread isNone:
            BaseCamera.last_access = time.time()

            # start background frame thread
            BaseCamera.thread = threading.Thread(target=self._thread)
            BaseCamera.thread.start()

            # wait until frames are availablewhile self.get_frame() isNone:
                time.sleep(0)

    defget_frame(self):
        """Return the current camera frame."""
        BaseCamera.last_access = time.time()

        # wait for a signal from the camera thread
        BaseCamera.event.wait()
        BaseCamera.event.clear()

        return BaseCamera.frame

    @staticmethoddefframes():
        """"Generator that returns frames from the camera."""raise RuntimeError('Must be implemented by subclasses.')

    @classmethoddef_thread(cls):
        """Camera background thread."""print('Starting camera thread.')
        frames_iterator = cls.frames()
        for frame in frames_iterator:
            BaseCamera.frame = frame
            BaseCamera.event.set()  # send signal to clients
            time.sleep(0)

            # if there hasn't been any clients asking for frames in# the last 10 seconds then stop the threadif time.time() - BaseCamera.last_access > 10:
                frames_iterator.close()
                print('Stopping camera thread due to inactivity.')
                break
        BaseCamera.thread = None

camera.py

#D:\gstreamer\1.0\x86\bin>gst-launch-1.0.exe  multifilesrc loop=true start-index=0 stop-index=0 location=d:/python/temp.png ! decodebin ! identity sleep-time=1000000 ! videoconvert ! autovideosinkimport shutil
import time
import os,sys
from PIL import Image, ImageFont, ImageDraw, ImageFile
from io import BytesIO
from base_camera import BaseCamera



im = Image.new("RGB", (300, 30), (220, 180, 180))
#im.format'JPEG'
dr = ImageDraw.Draw(im)
font = ImageFont.truetype(os.path.join("fonts", "msyh.ttf"), 16)
text =time.strftime("%m/%d  %H:%M:%S") +u"这是一段测试文本。"
dr.text((10, 5), text, font=font, fill="#000000")


im.save("d://python/temp.jpg")

dr.rectangle((0,0,300,500),fill="#FFFFFF")
text =time.strftime("%m/%d  %H:%M:%S") +u"这是一段测试文本。"
dr.text((10, 5),text, font=font, fill="#000000")
f = BytesIO()
f.name="sdf.jpg"
im.save(f,"JPEG")
f.seek(0)

f.close()

classCamera(BaseCamera):
    """An emulated camera implementation that streams a repeated sequence of
    files 1.jpg, 2.jpg and 3.jpg at a rate of one frame penr second."""
    imgs = [open(f + '.jpg', 'rb').read() for f in ['1', '2', '3']]

    @staticmethoddefframes():

        whileTrue:
            text =time.strftime("%m/%d  %H:%M:%S") +u"这是一段测试文本。"
            dr.rectangle((0,0,300,500),fill="#FFFFFF")
            dr.text((10, 5), text, font=font, fill="#000000")
            f = BytesIO()
            im.save(f,'JPEG')
            try :
              im.save("d:/python/temp.jpg")

            except :

                print("Unexpected error:", sys.exc_info()[0])
                pass#  shutil.copy("d:/python/temp2.png","d:/python/temp.png")
            f.seek(0)

            time.sleep(1)

            yield  f.read()  #Camera.imgs[int(time.time()) % 3]