Develop Reference

How to pass a fastapi response as input to another function

I have a post request that simply takes camera addresses from clients, Now I want to pass the response from this post request to another function that does the streaming via a web socket.
how can I pass the post-request function as input to get_stream ?
Post request function to take camera address
from fastapi import FastAPI, Request, WebSocket, WebSocketDisconnect
from pydantic import BaseModel
import cv2
import uvicorn
app = FastAPI()
class Address(BaseModel):
camera_id: Union[str, int] = 0
#app.post("/camera_id")
async def address(address: Address):
print(type(address.camera_id))
print('----------------------')
webcam = address.camera_id.isnumeric() or address.camera_id.endswith('.txt') or address.camera_id.lower().startswith(
('rtsp://', 'rtmp://', 'http://', 'https://'))
if webcam:
return address
else:
return {
'message': "Incorrect Camera Address",
'status': address.camera_id,
"expect_input": "The camera address should be (0, 1) or startwith ('rtsp://', 'rtmp://', 'http://', 'https://')"
}
Function that process frame via websocket
#app.websocket("/ws")
async def get_stream(websocket: WebSocket):
await websocket.accept()
camera_id = await address(parameter)
camera = cv2.VideoCapture(camera_id)
try:
while True:
frame = camera.frame()
if frame is not None:
ret, buffer = cv2.imencode('.jpg', frame)
await websocket.send_bytes(buffer.tobytes())
del frame, result
gc.collect()
torch.cuda.empty_cache()
else:
print('No frame is rendered')
break
except WebSocketDisconnect:
print("Client disconnected")
This is how I am calling my function in the get_stream function camera_id = await address(parameter)

How to stream video on web browser/HTML page by aiohttp?

My project uses socket.io to send/receive data.
I added aiohttp to help display the results on the browser.
import asyncio
from aiohttp import web
sio = socketio.AsyncServer(async_mode='`aiohttp`')
app = web.Application()
sio.attach(app)
I followed
https://us-pycon-2019-tutorial.readthedocs.io/aiohttp_file_uploading.html
to upload an image but I cannot upload a video.
def gen1():
# while True:
# if len(pm.list_image_display) > 1 :
image = cv2.imread("/home/duong/Pictures/Chess_Board.svg")
image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
# img = PIL.Image.new("RGB", (64, 64), color=(255,255,0))
image_pil = PIL.Image.fromarray(image)
fp = io.BytesIO()
image_pil.save(fp, format="JPEG")
content = fp.getvalue()
return content
async def send1():
print("11")
return web.Response(body=gen1(), content_type='image/jpeg')
How to display video via aiohttp on browsers?

To stream a video in aiohttp you may open a StreamResponse in response to the fetching of a img HTML node:
#routes.get('/video')
async def video_feed(request):
response = web.StreamResponse()
response.content_type = 'multipart/x-mixed-replace; boundary=frame'
await response.prepare(request)
for frame in frames('/dev/video0'):
await response.write(frame)
return response
and send your frames in the form of bytes:
def frames(path):
camera = cv2.VideoCapture(path)
if not camera.isOpened():
raise RuntimeError('Cannot open camera')
while True:
_, img = camera.read()
img = cv2.resize(img, (480, 320))
frame = cv2.imencode('.jpg', img)[1].tobytes()
yield b'--frame\r\nContent-Type: image/jpeg\r\n\r\n'+frame+b'\r\n'
This may be however network demanding as the bitrate required to send each frame individually is high. For real-time streaming with further compression you may want to use WebRTC implementations like aiortc.

Extract and analyze frames while recording using PiCamera, OpenCV

I'm streaming the video from my raspberryPi using piCamera to a web socket, so that I can view it within my local network.
I want to make my own motion detection script from scratch, therefore I want to get the first image from the video stream (which is going to be the plain background) then compare with a function next frames to the first one to check whether something has changed (I have written those functions separately), I am not really worrying about efficiency here.
MAIN ISSUE:
I want to get the data from those frames in a BytesIO object, then convert them to a 2D numpy array in B&W so I can perform operations. All this while keeping the stream going (I have in fact reduced the frame rate to 4 per second to make it run faster on my computer).
PROBLEM ENCOUNTERED WITH THE FOLLOWING CODE:
One part of the problem that I have identified is that the numbers are way off. In my settings my camera to have a resolution of around 640*480 (= 307,200 length numpy array pixels data in B&W) whereas my computations in len() return less that 100k pixels.
def main():
print('Initializing camera')
base_image = io.BytesIO()
image_captured = io.BytesIO()
with picamera.PiCamera() as camera:
camera.resolution = (WIDTH, HEIGHT)
camera.framerate = FRAMERATE
camera.vflip = VFLIP # flips image rightside up, as needed
camera.hflip = HFLIP # flips image left-right, as needed
sleep(1) # camera warm-up time
print('Initializing websockets server on port %d' % WS_PORT)
WebSocketWSGIHandler.http_version = '1.1'
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()
time.sleep(0.5)
camera.capture(base_image, use_video_port=True, format='jpeg')
base_data = np.asarray(bytearray(base_image.read()), dtype=np.uint64)
base_img_matrix = cv2.imdecode(base_data, cv2.IMREAD_GRAYSCALE)
while True:
camera.wait_recording(1)
#insert here the code for frame analysis
camera.capture(image_captured, use_video_port=True, format='jpeg')
data_next = np.asarray(bytearray(image_captured.read()), dtype=np.uint64)
next_img_matrix = cv2.imdecode(data_next, cv2.IMREAD_GRAYSCALE)
monitor_changes(base_img_matrix, next_img_matrix)
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()

Solved, basically the problem was all in the way I was handling data and BytesIO files. First of all I needed to use unsigned int8 as type of the file to decode id. Then I have switched to np.frombuffer to read the files in its entirety, because the base image is not going to change, hence it will read always the same thing, and the next one will be inizialized and eliminated in every while loop. Also I can replace cv2.IMREAD_GRAYSCALE with 0 in the function.
camera.start_recording(output, 'yuv')
base_image = io.BytesIO()
try:
print('Starting websockets thread')
websocket_thread.start()
print('Starting HTTP server thread')
http_thread.start()
print('Starting broadcast thread')
broadcast_thread.start()
time.sleep(0.5)
camera.capture(base_image, use_video_port=True, format='jpeg')
base_data = np.frombuffer(base_image.getvalue(), dtype=np.uint8)
base_img_matrix = cv2.imdecode(base_data, 0)
while True:
camera.wait_recording(0.25)
image_captured = io.BytesIO()
#insert here the code for frame analysis
camera.capture(image_captured, use_video_port=True, format='jpeg')
data_next = np.frombuffer(image_captured.getvalue(), dtype=np.uint8)
next_img_matrix = cv2.imdecode(data_next, cv2.IMREAD_GRAYSCALE)
monitor_changes(base_img_matrix, next_img_matrix)
image_captured.close()

Send JSON with image as bytes using WebSocket

I want to send and receive image from cv2.Videocapture using WebSocket.
It could get json, but it couldn't decoded.
We need result that can be opened using cv2.imshow().
Somebody help me...
This is Client
ret, image_np = cap.read()
IMAGE_SHAPE = image_np.shape
encoded_image = base64.b64encode(image_np)
print(type(encoded_image))
payload = {
'from': 'rasp',
'image': str(encoded_image),
'shape': IMAGE_SHAPE,
}
data = json.dumps(payload)
try:
# Send encoded image data.
await websocket.send(data)
# receive server message
received_data = await websocket.recv()
print('< {}'.format(received_data))
# image = base64.b64decode(received_data)
# np_image = np.fromstring(image, dtype=np.uint8)
# source = np_image.reshape(IMAGE_SHAPE)
return websocket
except Exception:
print('WebSocket send or receive error.')
exit(1)
This is Server
async def server_on(websocket, path):
payload = {
'from': 'image-server',
# 'result': {
# # Default is null.
# 'isPerson': <bool>,
# 'centerPoint': <(x, y)>,
# },
}
data = json.dumps(payload)
try:
payload = await websocket.recv()
receive_data = json.loads(payload)
# At this line doesnt work...
decoded_image = base64.b64decode(receive_data['image'])
image_np = np.fromstring(decoded_image, dtype=np.uint8)
source = image_np.reshape(receive_data['shape'])
await websocket.send(data)
except Exception:
websocket.close()
return

In your Client I would say that you have an extra operation not needed.
Based on your latest comment, you might not need to use: str(encoded_image).
You could try to use: base64.encodestring(image_np) that will send you back a string container.
ret, image_np = cap.read()
IMAGE_SHAPE = image_np.shape
encoded_image = base64.encodestring(image_np)
print(type(encoded_image))
payload = {
'from': 'rasp',
'image': encoded_image.decode('utf-8'),
'shape': IMAGE_SHAPE,
}

Python TCP socket send receive large delay

I used python socket to make a server on my Raspberry Pi 3 (Raspbian) and a client on my laptop (Windows 10). The server stream images to the laptop at a rate of 10fps, and can reach 15fps if I push it. The problem is when I want the laptop to send back a command based on the image, the frame rate drop sharply to 3fps. The process is like this:
Pi send img => Laptop receive img => Quick process => Send command based on process result => Pi receive command, print it => Pi send img => ...
The process time for each frame does not cause this (0.02s at most for each frame), so currently I am at a loss as to why the frame rate drop so much. The image is quite large, at around 200kB and the command is only a short string at 3B. The image is in matrix form and is pickled before sending, while the command is sent as is.
Can someone please explain to me why sending back such a short command would make the frame rate drop so much? And if possible, a solution for this problem. I tried making 2 servers, one dedicated to sending images and one for receiving command, but the result is the same.
Server:
import socket
import pickle
import time
import cv2
import numpy as np
from picamera.array import PiRGBArray
from picamera import PiCamera
from SendFrameInOO import PiImageServer
def main():
# initialize the server and time stamp
ImageServer = PiImageServer()
ImageServer2 = PiImageServer()
ImageServer.openServer('192.168.0.89', 50009)
ImageServer2.openServer('192.168.0.89', 50002)
# Initialize the camera object
camera = PiCamera()
camera.resolution = (320, 240)
camera.framerate = 10 # it seems this cannot go higher than 10
# unless special measures are taken, which may
# reduce image quality
camera.exposure_mode = 'sports' #reduce blur
rawCapture = PiRGBArray(camera)
# allow the camera to warmup
time.sleep(1)
# capture frames from the camera
print('<INFO> Preparing to stream video...')
timeStart = time.time()
for frame in camera.capture_continuous(rawCapture, format="bgr",
use_video_port = True):
# grab the raw NumPy array representing the image, then initialize
# the timestamp and occupied/unoccupied text
image = frame.array
imageData = pickle.dumps(image)
ImageServer.sendFrame(imageData) # send the frame data
# receive command from laptop and print it
command = ImageServer2.recvCommand()
if command == 'BYE':
print('BYE received, ending stream session...')
break
print(command)
# clear the stream in preparation for the next one
rawCapture.truncate(0)
print('<INFO> Video stream ended')
ImageServer.closeServer()
elapsedTime = time.time() - timeStart
print('<INFO> Total elapsed time is: ', elapsedTime)
if __name__ == '__main__': main()
Client:
from SupFunctions.ServerClientFunc import PiImageClient
import time
import pickle
import cv2
def main():
# Initialize
result = 'STP'
ImageClient = PiImageClient()
ImageClient2 = PiImageClient()
# Connect to server
ImageClient.connectClient('192.168.0.89', 50009)
ImageClient2.connectClient('192.168.0.89', 50002)
print('<INFO> Connection established, preparing to receive frames...')
timeStart = time.time()
# Receiving and processing frames
while(1):
# Receive and unload a frame
imageData = ImageClient.receiveFrame()
image = pickle.loads(imageData)
cv2.imshow('Frame', image)
key = cv2.waitKey(1) & 0xFF
# Exit when q is pressed
if key == ord('q'):
ImageClient.sendCommand('BYE')
break
ImageClient2.sendCommand(result)
ImageClient.closeClient()
elapsedTime = time.time() - timeStart
print('<INFO> Total elapsed time is: ', elapsedTime)
print('Press any key to exit the program')
#cv2.imshow('Picture from server', image)
cv2.waitKey(0)
if __name__ == '__main__': main()
PiImageServer and PiImageClient:
import socket
import pickle
import time
class PiImageClient:
def __init__(self):
self.s = None
self.counter = 0
def connectClient(self, serverIP, serverPort):
self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.s.connect((serverIP, serverPort))
def closeClient(self):
self.s.close()
def receiveOneImage(self):
imageData = b''
lenData = self.s.recv(8)
length = pickle.loads(lenData) # should be 921764 for 640x480 images
print('Data length is:', length)
while len(imageData) < length:
toRead = length-len(imageData)
imageData += self.s.recv(4096 if toRead>4096 else toRead)
#if len(imageData)%200000 <= 4096:
# print('Received: {} of {}'.format(len(imageData), length))
return imageData
def receiveFrame(self):
imageData = b''
lenData = self.s.recv(8)
length = pickle.loads(lenData)
print('Data length is:', length)
'''length = 921764 # for 640x480 images
length = 230563 # for 320x240 images'''
while len(imageData) < length:
toRead = length-len(imageData)
imageData += self.s.recv(4096 if toRead>4096 else toRead)
#if len(imageData)%200000 <= 4096:
# print('Received: {} of {}'.format(len(imageData), length))
self.counter += 1
if len(imageData) == length:
print('Successfully received frame {}'.format(self.counter))
return imageData
def sendCommand(self, command):
if len(command) != 3:
print('<WARNING> Length of command string is different from 3')
self.s.send(command.encode())
print('Command {} sent'.format(command))
class PiImageServer:
def __init__(self):
self.s = None
self.conn = None
self.addr = None
#self.currentTime = time.time()
self.currentTime = time.asctime(time.localtime(time.time()))
self.counter = 0
def openServer(self, serverIP, serverPort):
print('<INFO> Opening image server at {}:{}'.format(serverIP,
serverPort))
self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.s.bind((serverIP, serverPort))
self.s.listen(1)
print('Waiting for client...')
self.conn, self.addr = self.s.accept()
print('Connected by', self.addr)
def closeServer(self):
print('<INFO> Closing server...')
self.conn.close()
self.s.close()
#self.currentTime = time.time()
self.currentTime = time.asctime(time.localtime(time.time()))
print('Server closed at', self.currentTime)
def sendOneImage(self, imageData):
print('<INFO> Sending only one image...')
imageDataLen = len(imageData)
lenData = pickle.dumps(imageDataLen)
print('Sending image length')
self.conn.send(lenData)
print('Sending image data')
self.conn.send(imageData)
def sendFrame(self, frameData):
self.counter += 1
print('Sending frame ', self.counter)
frameDataLen = len(frameData)
lenData = pickle.dumps(frameDataLen)
self.conn.send(lenData)
self.conn.send(frameData)
def recvCommand(self):
commandData = self.conn.recv(3)
command = commandData.decode()
return command

I believe the problem is two-fold. First, you are serializing all activity: The server is sending a complete image, then instead of continuing on to send the next image (which would better fit the definition of "streaming"), it is stopping, waiting for all bytes of the previous image to make themselves across the network to the client, then for the client to receive all bytes of the image, unpickle it, send a response and for the response to then make its way across the wire to the server.
Is there a reason you need them to be in lockstep like this? If not, try to parallelize the two sides. Have your server create a separate thread to listen for commands coming back (or simply use select to determine when the command socket has something to receive).
Second, you are likely being bitten by Nagle's algorithm (https://en.wikipedia.org/wiki/Nagle%27s_algorithm), which is intended to prevent sending numerous packets with small payloads (but lots of overhead) across the network. So, your client-side kernel has gotten your three-bytes of command data and has buffered it, waiting for you to provide more data before it sends the data to the server (it will eventually send it anyway, after a delay). To change that, you would want to use the TCP_NODELAY socket option on the client side (see https://stackoverflow.com/a/31827588/1076479).