Create mjpeg stream from jpeg images in python

Question

I need to serve graphics in real time, and I would like to stream the mjpeg over http (so it's easy to include graphics on a web page with a simple tag).

Is it possible to create a mjpeg stream from multiple jpeg images in real time?

My strategy:

• Print 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 

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

• Just enter the serial jpeg binaries under the following conditions:

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

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

  • add a boundary line at the end of each jpeg stream.

     --boudary-- 

---

Questions:

You did it,

You know the python module that does this,

Do you think this will work

Do you have any advice?

Answer 1

I got this as 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' 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() 

Answer 2

You can use the flash framework for this.
This is not just for mjpeg.
I adapted the code from here: https://blog.miguelgrinberg.com/post/video-streaming-with-flask

APP.py

 #!/usr/bin/env python from importlib import import_module import os from flask import Flask, render_template, Response # import camera driver if 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('/') def index(): """Video streaming home page.""" return render_template('index.html') def gen(camera): """Video streaming generator function.""" while True: 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') 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', 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 class CameraEvent(object): """An Event-like class that signals all active clients when a new frame is available. """ def __init__(self): self.events = {} def wait(self): """Invoked from each client thread to wait for the next frame.""" ident = get_ident() if ident not in 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() def set(self): """Invoked by the camera thread when a new frame is available.""" now = time.time() remove = None for ident, event in self.events.items(): if not event[0].isSet(): # if this client 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 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 it if now - event[1] > 5: remove = ident if remove: del self.events[remove] def clear(self): """Invoked from each client thread after a frame was processed.""" self.events[get_ident()][0].clear() class BaseCamera(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 is None: BaseCamera.last_access = time.time() # start background frame thread BaseCamera.thread = threading.Thread(target=self._thread) BaseCamera.thread.start() # wait until frames are available while self.get_frame() is None: time.sleep(0) def get_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 @staticmethod def frames(): """"Generator that returns frames from the camera.""" raise RuntimeError('Must be implemented by subclasses.') @classmethod def _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 thread if 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 ! autovideosink import 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() class Camera(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']] @staticmethod def frames(): while True: 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]