This assignment must be done in Python. The objective of this assignment is to i

Question

This assignment must be done in Python. The objective of this assignment is to implement a streaming video server and client using a .mpg video. The client will use the real-time streaming protocol (RTSP) to control the actions of the server. The server will use the real-time protocol (RTP) to packetize the video for transport over UDP. You may find the following libraries useful: Python Pillow library and/or CV2 library , and/or Tkinter library. Pillow provides tools for the python image library.  

Explanation / Answer

#!/usr/bin/env python

import sys
import io
import os
import shutil
from subprocess import Popen, PIPE
from string import Template
from struct import Struct
from threading import Thread
from time import sleep, time
from http.server import HTTPServer, BaseHTTPRequestHandler
from wsgiref.simple_server import make_server

import picamera
from ws4py.websocket import WebSocket
from ws4py.server.wsgirefserver import WSGIServer, WebSocketWSGIRequestHandler
from ws4py.server.wsgiutils import WebSocketWSGIApplication

###########################################
# CONFIGURATION
WIDTH = 640
HEIGHT = 480
FRAMERATE = 24
HTTP_PORT = 8082
WS_PORT = 8084
COLOR = u'#444'
BGCOLOR = u'#333'
JSMPEG_MAGIC = b'jsmp'
JSMPEG_HEADER = Struct('>4sHH')
###########################################
class StreamingHttpHandler(BaseHTTPRequestHandler):
def do_HEAD(self):
self.do_GET()

def do_GET(self):
if self.path == '/':
self.send_response(301)
self.send_header('Location', '/index.html')
self.end_headers()
return
elif self.path == '/jsmpg.js':
content_type = 'application/javascript'
content = self.server.jsmpg_content
elif self.path == '/index.html':
content_type = 'text/html; charset=utf-8'
tpl = Template(self.server.index_template)
content = tpl.safe_substitute(dict(
ADDRESS='%s:%d' % (self.request.getsockname()[0], WS_PORT),
WIDTH=WIDTH, HEIGHT=HEIGHT, COLOR=COLOR, BGCOLOR=BGCOLOR))
else:
self.send_error(404, 'File not found')
return
content = content.encode('utf-8')
self.send_response(200)
self.send_header('Content-Type', content_type)
self.send_header('Content-Length', len(content))
self.send_header('Last-Modified', self.date_time_string(time()))
self.end_headers()
if self.command == 'GET':
self.wfile.write(content)
class StreamingHttpServer(HTTPServer):
def __init__(self):
super(StreamingHttpServer, self).__init__(
('', HTTP_PORT), StreamingHttpHandler)
with io.open('index.html', 'r') as f:
self.index_template = f.read()
with io.open('jsmpg.js', 'r') as f:
self.jsmpg_content = f.read()
class StreamingWebSocket(WebSocket):
def opened(self):
self.send(JSMPEG_HEADER.pack(JSMPEG_MAGIC, WIDTH, HEIGHT), binary=True)

class BroadcastOutput(object):
def __init__(self, camera):
print('Spawning background conversion process')
self.converter = Popen([
'avconv',
'-f', 'rawvideo',
'-pix_fmt', 'yuv420p',
'-s', '%dx%d' % camera.resolution,
'-r', str(float(camera.framerate)),
'-i', '-',
'-f', 'mpeg1video',
'-b', '800k',
'-r', str(float(camera.framerate)),
'-'],
stdin=PIPE, stdout=PIPE, stderr=io.open(os.devnull, 'wb'),
shell=False, close_fds=True)

def write(self, b):
self.converter.stdin.write(b)

def flush(self):
print('Waiting for background conversion process to exit')
self.converter.stdin.close()
self.converter.wait()

class BroadcastThread(Thread):
def __init__(self, converter, websocket_server):
super(BroadcastThread, self).__init__()
self.converter = converter
self.websocket_server = websocket_server

def run(self):
try:
while True:
buf = self.converter.stdout.read(512)
if buf:
self.websocket_server.manager.broadcast(buf, binary=True)
elif self.converter.poll() is not None:
break
finally:
self.converter.stdout.close()
def main():
print('Initializing camera')
with picamera.PiCamera() as camera:
camera.resolution = (WIDTH, HEIGHT)
camera.framerate = FRAMERATE
sleep(1) # camera warm-up time
print('Initializing websockets server on port %d' % WS_PORT)
websocket_server = make_server(
'', WS_PORT,
server_class=WSGIServer,
handler_class=WebSocketWSGIRequestHandler,
app=WebSocketWSGIApplication(handler_cls=StreamingWebSocket))
websocket_server.initialize_websockets_manager()
websocket_thread = Thread(target=websocket_server.serve_forever)
print('Initializing HTTP server on port %d' % HTTP_PORT)
http_server = StreamingHttpServer()
http_thread = Thread(target=http_server.serve_forever)
print('Initializing broadcast thread')
output = BroadcastOutput(camera)
broadcast_thread = BroadcastThread(output.converter, websocket_server)
print('Starting recording')
camera.start_recording(output, 'yuv')
try:
print('Starting websockets thread')
websocket_thread.start()
print('Starting HTTP server thread')
http_thread.start()
print('Starting broadcast thread')
broadcast_thread.start()
while True:
camera.wait_recording(1)
except KeyboardInterrupt:
pass
finally:
print('Stopping recording')
camera.stop_recording()
print('Waiting for broadcast thread to finish')
broadcast_thread.join()
print('Shutting down HTTP server')
http_server.shutdown()
print('Shutting down websockets server')
websocket_server.shutdown()
print('Waiting for HTTP server thread to finish')
http_thread.join()
print('Waiting for websockets thread to finish')
websocket_thread.join()

if __name__ == '__main__':
main()

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