python - UDP视频流延迟-OPENCV Python

Question

我有流视频UDP，但是数据包被延迟并且困惑。
这是我从opencv网站上获取的引用代码。

但是当我给Socket.Stream使用TCP连接时，它的流很好并且帧是连续的。

Server.py

import socket
import numpy
import time
import cv2

UDP_IP = "127.0.0.1"
UDP_PORT = 999
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind((UDP_IP, UDP_PORT))


s=b''

while True:

  data, addr = sock.recvfrom(46080)

  s += data

  if len(s) == (46080*20):

    frame = numpy.fromstring (s,dtype=numpy.uint8)
    frame = frame.reshape (480,640,3)

    cv2.imshow('frame',frame)

    s=b''

  if cv2.waitKey(1) & 0xFF == ord ('q'):
    break

客户端

import socket
import numpy as np
import cv2

UDP_IP = '127.0.0.1'
UDP_PORT = 999
cap = cv2.VideoCapture(0)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH,320)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT,240)
def xrange(x):

  return iter(range(x))
while (True):
  ret, frame = cap.read()
  cv2.imshow('frame', frame)
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  d = frame.flatten()
  s = d.tostring()
  for i in xrange(20):
    sock.sendto(s[i * 46080:(i + 1) * 46080], (UDP_IP, UDP_PORT))
  if cv2.waitKey(1) & 0xFF == ord('q'):
    break

cap.release()
cv2.destroyAllWindows()

Answer 1

看起来client.py脚本发送UDP帧的速度(比server.py将它们拼接在一起的速度快得多)。我不知道为什么会这样。也许在每次迭代后增加了字节s的大小之后，Python需要找到一个新的位置来存储s，这会使它丢失从client.py发送的帧。但是，同步它们的一种方法是在client.py确认收到帧之后，告诉server.py发送。

在下面的代码中，server.py将通过b'eframe'监听图像的开始传输。 server.py将使用client.py连续答复b'n'以提示发送下一帧。 client.py将通过发送b'eframe'通知图像结束

server.py

import socket
import numpy
import time
import cv2

UDP_IP = "127.0.0.1"
UDP_PORT = 999
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind((UDP_IP, UDP_PORT))


s=b''

while True:

  data, addr = sock.recvfrom(6) # b'eframe' is 6 byte long

  if data == b'sframe':
    while True:
      sock.sendto(b'n', addr)
      data, addr = sock.recvfrom(46080)
      if data == b'eframe':
        break
      s += data

  if len(s) == (46080*20):

    frame = numpy.fromstring (s,dtype=numpy.uint8)
    frame = frame.reshape (480,640,3)

    cv2.imshow('frame',frame)

    s=b''

  if cv2.waitKey(1) & 0xFF == ord ('q'):
    break

client.py

import socket
import numpy as np
import cv2

UDP_IP = '127.0.0.1'
UDP_PORT = 999
cap = cv2.VideoCapture(0)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH,320)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT,240)
def xrange(x):

  return iter(range(x))
while (True):
  ret, frame = cap.read()
  cv2.imshow('frame', frame)
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  d = frame.flatten()
  s = d.tostring()

  sock.sendto(b'sframe', (UDP_IP, UDP_PORT))
  for i in xrange(20):
    data, addr = sock.recvfrom(1) # b'n' is 1 byte long
    if data == b'n':
      sock.sendto(s[i * 46080:(i + 1) * 46080], (UDP_IP, UDP_PORT))
  data, addr = sock.recvfrom(1)
  sock.sendto(b'eframe', (UDP_IP, UDP_PORT))

  if cv2.waitKey(1) & 0xFF == ord('q'):
    break

cap.release()
cv2.destroyAllWindows()