E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\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_opencv').Camera
#     # Camera = import_module('camera_' + os.environ['CAMERA']).Camera
#     # print(os.environ['CAMERA'])
# else:
#     from camera import Camera

from camera_opencv 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."""
    yield b'--frame\r\n'
    while True:
        frame = camera.get_frame()
        yield b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n--frame\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)

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\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's 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'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 it
                if now - event[1] > 5:
                    remove = ident
        if remove:
            del self.events[remove]

    def clear(self):
        """Invoked from each client's 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 first frame is available
            BaseCamera.event.wait()

    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

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\camera.py

import time
from base_camera import BaseCamera


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 per second."""
    imgs = [open(f + '.jpg', 'rb').read() for f in ['1', '2', '3']]

    @staticmethod
    def frames():
        while True:
            yield Camera.imgs[int(time.time()) % 3]
            time.sleep(1)

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\camera_opencv.py

import os
import cv2
from base_camera import BaseCamera


class Camera(BaseCamera):
    video_source = 0

    def __init__(self):
        if os.environ.get('OPENCV_CAMERA_SOURCE'):
            Camera.set_video_source(int(os.environ['OPENCV_CAMERA_SOURCE']))
        super(Camera, self).__init__()

    @staticmethod
    def set_video_source(source):
        Camera.video_source = source

    @staticmethod
    def frames():
        camera = cv2.VideoCapture(Camera.video_source)
        if not camera.isOpened():
            raise RuntimeError('Could not start camera.')

        while True:
            # read current frame
            _, img = camera.read()

            # encode as a jpeg image and return it
            yield cv2.imencode('.jpg', img)[1].tobytes()

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\camera_pi.py

import io
import time
import picamera
from base_camera import BaseCamera


class Camera(BaseCamera):
    @staticmethod
    def frames():
        with picamera.PiCamera() as camera:
            # let camera warm up
            time.sleep(2)

            stream = io.BytesIO()
            for _ in camera.capture_continuous(stream, 'jpeg',
                                                 use_video_port=True):
                # return current frame
                stream.seek(0)
                yield stream.read()

                # reset stream for next frame
                stream.seek(0)
                stream.truncate()

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\camera_v4l2.py

import io
from PIL import Image
import select
import v4l2capture
from base_camera import BaseCamera


class Camera(BaseCamera):
    """Requires python-v4l2capture module: https://github.com/gebart/python-v4l2capture"""

    video_source = "/dev/video0"

    @staticmethod
    def frames():
        video = v4l2capture.Video_device(Camera.video_source)
        # Suggest an image size. The device may choose and return another if unsupported
        size_x = 640
        size_y = 480
        size_x, size_y = video.set_format(size_x, size_y)
        video.create_buffers(1)
        video.queue_all_buffers()
        video.start()
        bio = io.BytesIO()

        try:
            while True:
                select.select((video,), (), ())  # Wait for the device to fill the buffer.
                image_data = video.read_and_queue()
                image = Image.frombytes("RGB", (size_x, size_y), image_data)
                image.save(bio, format="jpeg")
                yield bio.getvalue()
                bio.seek(0)
                bio.truncate()
        finally:
            video.close()

E:\song2\树莓派视频流\flask_opencv_video_stream\flask-video-streaming\templates\index.html

<html>
  <head>
    <title>Video Streaming Demonstration</title>
  </head>
  <body>
    <h1>Video Streaming Demonstration</h1>
    <img src="{{ url_for('video_feed') }}">
  </body>
</html>