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rocnet:cam-en

Camera Streaming

Python

Python Script

# Web streaming example
# Source code from the official PiCamera package
# http://picamera.readthedocs.io/en/latest/recipes2.html#web-streaming
 
import io
import picamera
import logging
import socketserver
from threading import Condition
from http import server
 
PAGE="""\
<html>
<head>
<title>V200 Camera</title>
</head>
<body>
<img src="stream.mjpg" width="320" height="240">
</body>
</html>
"""
 
class StreamingOutput(object):
    def __init__(self):
        self.frame = None
        self.buffer = io.BytesIO()
        self.condition = Condition()
 
    def write(self, buf):
        if buf.startswith(b'\xff\xd8'):
            # New frame, copy the existing buffer's content and notify all
            # clients it's available
            self.buffer.truncate()
            with self.condition:
                self.frame = self.buffer.getvalue()
                self.condition.notify_all()
            self.buffer.seek(0)
        return self.buffer.write(buf)
 
class StreamingHandler(server.BaseHTTPRequestHandler):
    def do_GET(self):
        if self.path == '/':
            self.send_response(301)
            self.send_header('Location', '/index.html')
            self.end_headers()
        elif self.path == '/index.html':
            content = PAGE.encode('utf-8')
            self.send_response(200)
            self.send_header('Content-Type', 'text/html')
            self.send_header('Content-Length', len(content))
            self.end_headers()
            self.wfile.write(content)
        elif self.path == '/stream.mjpg':
            self.send_response(200)
            self.send_header('Age', 0)
            self.send_header('Cache-Control', 'no-cache, private')
            self.send_header('Pragma', 'no-cache')
            self.send_header('Content-Type', 'multipart/x-mixed-replace; boundary=FRAME')
            self.end_headers()
            try:
                while True:
                    with output.condition:
                        output.condition.wait()
                        frame = output.frame
                    self.wfile.write(b'--FRAME\r\n')
                    self.send_header('Content-Type', 'image/jpeg')
                    self.send_header('Content-Length', len(frame))
                    self.end_headers()
                    self.wfile.write(frame)
                    self.wfile.write(b'\r\n')
            except Exception as e:
                logging.warning(
                    'Removed streaming client %s: %s',
                    self.client_address, str(e))
        else:
            self.send_error(404)
            self.end_headers()
 
class StreamingServer(socketserver.ThreadingMixIn, server.HTTPServer):
    allow_reuse_address = True
    daemon_threads = True
 
with picamera.PiCamera(resolution='320x240', framerate=12) as camera:
    output = StreamingOutput()
    #Uncomment the next line to change your Pi's Camera rotation (in degrees)
    #camera.rotation = 90
    camera.start_recording(output, format='mjpeg')
    try:
        address = ('', 8081)
        server = StreamingServer(address, StreamingHandler)
        server.serve_forever()
    finally:
        camera.stop_recording()

Start the script with:

python3 cam.py

This uses about 5% CPU on a RPi 4+.

Open the URL in the browser with:

http://raspberry:8081

Where <raspberry> should be the hostname or IP address of the Raspberry Pi on which the Pythons script runs.

Python WEB Server Output

<html>
<head>
<title>V200 Camera</title>
</head>
<body>
<img src="stream.mjpg" width="320" height="240">
</body>
</html>


Viewers

Text

To enable MJPEG streaming in a text object, the text content must be set to:

mjpg:<host>:<port>

For example:

mjpg:192.168.100.167:8081

Loco Throttle

Set the camera host and port on the Interface Tab of the loco properties.

IE Solutions

MS IE does not support mjpg video streaming.


Splitting

    00000130: 55 E6 9D 09 E3 78 60 4E 31 81 BB 05 94 12 A3 38 |U....x`N1......8|
    00000140: 27 6B 74 23 D3 03 35 B5 2E 6E 58 B6 BF AD 46 D3 |'kt#..5..nX...F.|
    00000150: B6 FB 7E 07 FF D9 0D 0A 2D 2D 46 52 41 4D 45 0D |..~.....--FRAME.|
    00000160: 0A 43 6F 6E 74 65 6E 74 2D 54 79 70 65 3A 20 69 |.Content-Type: i|
    00000170: 6D 61 67 65 2F 6A 70 65 67 0D 0A 43 6F 6E 74 65 |mage/jpeg..Conte|
    00000180: 6E 74 2D 4C 65 6E 67 74 68 3A 20 31 32 35 32 34 |nt-Length: 12524|
    00000190: 33 0D 0A 0D 0A FF D8 FF DB 00 84 00 01 01 01 01 |3...............|
    000001A0: 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 |................|
    000001B0: 01 01 01 01 01 01 01 01 01 01 01 01 01 01 02 02 |................|
    
    
    00000120: 8D B9 66 EE EF AD 96 DD 74 E4 76 DF FA 63 FA AD |..f.....t.v..c..|
    00000130: 29 2D 62 AD A6 AA FA FC B9 B4 F9 9F FF D9 0D 0A |)-b.............|
    00000140: 2D 2D 46 52 41 4D 45 0D 0A 43 6F 6E 74 65 6E 74 |--FRAME..Content|
    00000150: 2D 54 79 70 65 3A 20 69 6D 61 67 65 2F 6A 70 65 |-Type: image/jpe|
    00000160: 67 0D 0A 43 6F 6E 74 65 6E 74 2D 4C 65 6E 67 74 |g..Content-Lengt|
    00000170: 68 3A 20 34 37 30 37 37 0D 0A 0D 0A FF D8 FF DB |h: 47077........|
    00000180: 00 84 00 01 01 01 01 01 01 01 01 01 01 01 01 01 |................|
    00000190: 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 |................|
    000001A0: 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 |................|

Source: https://stackoverflow.com/questions/21702477/how-to-parse-mjpeg-http-stream-from-ip-camera

import cv2
import urllib 
import numpy as np
 
stream = urllib.urlopen('http://localhost:8080/frame.mjpg')
bytes = ''
while True:
    bytes += stream.read(1024)
    a = bytes.find('\xff\xd8')
    b = bytes.find('\xff\xd9')
    if a != -1 and b != -1:
        jpg = bytes[a:b+2]
        bytes = bytes[b+2:]
        i = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8), cv2.CV_LOAD_IMAGE_COLOR)
        cv2.imshow('i', i)
        if cv2.waitKey(1) == 27:
            exit(0)   
rocnet/cam-en.txt · Last modified: 2019/08/16 23:42 by rainerk