如何有效地从IP摄像头读取和保存视频？

Question

我有一个python脚本，用于通过家庭网络从ip摄像头抓取图像并添加日期时间信息。在12小时内，它可以拍摄大约200,000张照片。但是当使用zoneminder（相机监控软件）时，相机会在7小时内管理250,000个。

我想知道是否有人可以帮助我提高脚本效率我尝试使用线程模块创建2个线程但是它没有帮助我不确定我是否已经错误地实现了它。以下是我目前使用的代码：

#!/usr/bin/env python

# My First python script to grab images from an ip camera

import requests
import time
import urllib2
import sys
import os
import PIL
from PIL import ImageFont
from PIL import Image
from PIL import ImageDraw
import datetime
from datetime import datetime
import threading

timecount = 43200
lock = threading.Lock()

wdir = "/workdir/"

y = len([f for f in os.listdir(wdir) 
     if f.startswith('Cam1') and os.path.isfile(os.path.join(wdir, f))])

def looper(timeCount):
   global y
   start = time.time()
   keepLooping = True
   while keepLooping:
    with lock:
        y += 1
    now = datetime.now()
    dte = str(now.day) + ":" +  str(now.month) + ":" + str(now.year)
    dte1 = str(now.hour) + ":" + str(now.minute) + ":" + str(now.second) + "." + str(now.microsecond)
    cname = "Cam1:"
    dnow = """Date: %s """ % (dte)
    dnow1 = """Time: %s""" % (dte1)
    buffer = urllib2.urlopen('http://(ip address)/snapshot.cgi?user=uname&pwd=password').read()
    img = str(wdir) + "Cam1-" + str('%010d' % y) + ".jpg"
    f = open(img, 'wb')
    f.write(buffer) 
    f.close()
    if time.time()-start > timeCount:
           keepLooping = False
    font = ImageFont.truetype("/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf",10)
    img=Image.open(img)
    draw = ImageDraw.Draw(img)
    draw.text((0, 0),cname,fill="white",font=font)
    draw.text((0, 10),dnow,fill="white",font=font)
    draw.text((0, 20),dnow1,fill="white",font=font)
    draw = ImageDraw.Draw(img)
    draw = ImageDraw.Draw(img)
    img.save(str(wdir) + "Cam1-" + str('%010d' % y) + ".jpg")

for i in range(2):
        thread = threading.Thread(target=looper,args=(timecount,))
        thread.start()
        thread.join()

如何改进此脚本或如何从相机打开流然后从流中抓取图像？那甚至可以提高效率/捕获率吗？

修改

感谢kobejohn的帮助，我提出了以下实施方案。在12小时的时间里，它已经从2个单独的摄像头（同时）获得了超过420,000张照片，每张照片同时在他们自己的线程上运行，相比之下我的原始实现中的大约200,000张。以下代码将并行运行2个摄像头（或足够接近它）并向其添加文本：

import base64
from datetime import datetime
import httplib
import io
import os
import time

from PIL import ImageFont
from PIL import Image
from PIL import ImageDraw

import multiprocessing

wdir = "/workdir/"
stream_urlA = '192.168.3.21'
stream_urlB = '192.168.3.23'
usernameA = ''
usernameB = ''
password = ''

y = sum(1 for f in os.listdir(wdir) if f.startswith('CamA') and os.path.isfile(os.path.join(wdir, f)))
x = sum(1 for f in os.listdir(wdir) if f.startswith('CamB') and os.path.isfile(os.path.join(wdir, f)))

def main():
    time_count = 43200
#    time_count = 1
    procs = list()
    for i in range(1):
        p = multiprocessing.Process(target=CameraA, args=(time_count, y,))
        q = multiprocessing.Process(target=CameraB, args=(time_count, x,))
        procs.append(p)
        procs.append(q)
        p.start()
        q.start()
    for p in procs:
        p.join()

def CameraA(time_count, y):
    y = y
    h = httplib.HTTP(stream_urlA)
    h.putrequest('GET', '/videostream.cgi')
    h.putheader('Authorization', 'Basic %s' % base64.encodestring('%s:%s' % (usernameA, password))[:-1])
    h.endheaders()
    errcode, errmsg, headers = h.getreply()
    stream_file = h.getfile()
    start = time.time()
    end = start + time_count
    while time.time() <= end:
    y += 1
        now = datetime.now()
        dte = str(now.day) + "-" + str(now.month) + "-" + str(now.year)
        dte1 = str(now.hour) + ":" + str(now.minute) + ":" + str(now.second) + "." + str(now.microsecond)
        cname = "Cam#: CamA"
        dnow = """Date: %s """ % dte
        dnow1 = """Time: %s""" % dte1
        # your camera may have a different streaming format
        # but I think you can figure it out from the debug style below
        source_name = stream_file.readline()    # '--ipcamera'
        content_type = stream_file.readline()    # 'Content-Type: image/jpeg'
        content_length = stream_file.readline()   # 'Content-Length: 19565'
        #print 'confirm/adjust content (source?): ' + source_name
        #print 'confirm/adjust content (type?): ' + content_type
        #print 'confirm/adjust content (length?): ' + content_length
        # find the beginning of the jpeg data BEFORE pulling the jpeg framesize
        # there must be a more efficient way, but hopefully this is not too bad
        b1 = b2 = b''
        while True:
            b1 = stream_file.read(1)
            while b1 != chr(0xff):
                b1 = stream_file.read(1)
            b2 = stream_file.read(1)
            if b2 == chr(0xd8):
                break
        # pull the jpeg data
        framesize = int(content_length[16:])
        jpeg_stripped = b''.join((b1, b2, stream_file.read(framesize - 2)))
        # throw away the remaining stream data. Sorry I have no idea what it is
        junk_for_now = stream_file.readline()
        # convert directly to an Image instead of saving / reopening
        # thanks to SO: http://stackoverflow.com/a/12020860/377366
        image_as_file = io.BytesIO(jpeg_stripped)
        image_as_pil = Image.open(image_as_file)
        draw = ImageDraw.Draw(image_as_pil)
        draw.text((0, 0), cname, fill="white")
        draw.text((0, 10), dnow, fill="white")
        draw.text((0, 20), dnow1, fill="white")
        img_name = "CamA-" + str('%010d' % y) + ".jpg"
        img_path = os.path.join(wdir, img_name)
        image_as_pil.save(img_path)

def CameraB(time_count, x):
    x = x
    h = httplib.HTTP(stream_urlB)
    h.putrequest('GET', '/videostream.cgi')
    h.putheader('Authorization', 'Basic %s' % base64.encodestring('%s:%s' % (usernameB, password))[:-1])
    h.endheaders()
    errcode, errmsg, headers = h.getreply()
    stream_file = h.getfile()
    start = time.time()
    end = start + time_count
    while time.time() <= end:
    x += 1
        now = datetime.now()
        dte = str(now.day) + "-" + str(now.month) + "-" + str(now.year)
        dte1 = str(now.hour) + ":" + str(now.minute) + ":" + str(now.second) + "." + str(now.microsecond)
        cname = "Cam#: CamB"
        dnow = """Date: %s """ % dte
        dnow1 = """Time: %s""" % dte1
        # your camera may have a different streaming format
        # but I think you can figure it out from the debug style below
        source_name = stream_file.readline()    # '--ipcamera'
        content_type = stream_file.readline()    # 'Content-Type: image/jpeg'
        content_length = stream_file.readline()   # 'Content-Length: 19565'
        #print 'confirm/adjust content (source?): ' + source_name
        #print 'confirm/adjust content (type?): ' + content_type
        #print 'confirm/adjust content (length?): ' + content_length
        # find the beginning of the jpeg data BEFORE pulling the jpeg framesize
        # there must be a more efficient way, but hopefully this is not too bad
        b1 = b2 = b''
        while True:
            b1 = stream_file.read(1)
            while b1 != chr(0xff):
                b1 = stream_file.read(1)
            b2 = stream_file.read(1)
            if b2 == chr(0xd8):
                break
        # pull the jpeg data
        framesize = int(content_length[16:])
        jpeg_stripped = b''.join((b1, b2, stream_file.read(framesize - 2)))
        # throw away the remaining stream data. Sorry I have no idea what it is
        junk_for_now = stream_file.readline()
        # convert directly to an Image instead of saving / reopening
        # thanks to SO: http://stackoverflow.com/a/12020860/377366
        image_as_file = io.BytesIO(jpeg_stripped)
        image_as_pil = Image.open(image_as_file)
        draw = ImageDraw.Draw(image_as_pil)
        draw.text((0, 0), cname, fill="white")
        draw.text((0, 10), dnow, fill="white")
        draw.text((0, 20), dnow1, fill="white")
        img_name = "CamB-" + str('%010d' % x) + ".jpg"
        img_path = os.path.join(wdir, img_name)
        image_as_pil.save(img_path)

if __name__ == '__main__':
    main()

编辑（2014年5月26日）：

我花了2个月的大部分时间尝试更新此脚本/程序以使用python 3，但完全无法让它做任何事情。有人能指出我正确的方向吗？

我已经尝试了2to3脚本，但它只是更改了几个条目，但我仍然无法使其正常运行。

Answer 1

*编辑我之前将GIL归咎于愚蠢的行为。这是一个I / O绑定进程，而不是受CPU限制的进程。因此，多处理不是一个有意义的解决方案。

---

*更新我终于找到了一个具有与你相同的流媒体界面的演示ip摄像头（我认为）。使用流接口，它只进行一次连接，然后从数据流中读取，就像它是一个提取jpg图像帧的文件一样。使用下面的代码，我抓住了2秒==＆gt;我认为27帧可以在7小时内推断出大约300k的图像。

如果你想获得更多，你可以将图像修改和文件写入一个单独的线程，并让一个工作人员这样做，而主线程只是从流中获取并将jpeg数据发送给工作者。

import base64
from datetime import datetime
import httplib
import io
import os
import time

from PIL import ImageFont
from PIL import Image
from PIL import ImageDraw


wdir = "workdir"
stream_url = ''
username = ''
password = ''


def main():
    time_count = 2
    looper_stream(time_count)


def looper_stream(time_count):
    h = httplib.HTTP(stream_url)
    h.putrequest('GET', '/videostream.cgi')
    h.putheader('Authorization', 'Basic %s' % base64.encodestring('%s:%s' % (username, password))[:-1])
    h.endheaders()
    errcode, errmsg, headers = h.getreply()
    stream_file = h.getfile()
    start = time.time()
    end = start + time_count
    while time.time() <= end:
        now = datetime.now()
        dte = str(now.day) + "-" + str(now.month) + "-" + str(now.year)
        dte1 = str(now.hour) + "-" + str(now.minute) + "-" + str(now.second) + "." + str(now.microsecond)
        cname = "Cam1-"
        dnow = """Date: %s """ % dte
        dnow1 = """Time: %s""" % dte1
        # your camera may have a different streaming format
        # but I think you can figure it out from the debug style below
        source_name = stream_file.readline()    # '--ipcamera'
        content_type = stream_file.readline()    # 'Content-Type: image/jpeg'
        content_length = stream_file.readline()   # 'Content-Length: 19565'
        print 'confirm/adjust content (source?): ' + source_name
        print 'confirm/adjust content (type?): ' + content_type
        print 'confirm/adjust content (length?): ' + content_length
        # find the beginning of the jpeg data BEFORE pulling the jpeg framesize
        # there must be a more efficient way, but hopefully this is not too bad
        b1 = b2 = b''
        while True:
            b1 = stream_file.read(1)
            while b1 != chr(0xff):
                b1 = stream_file.read(1)
            b2 = stream_file.read(1)
            if b2 == chr(0xd8):
                break
        # pull the jpeg data
        framesize = int(content_length[16:])
        jpeg_stripped = b''.join((b1, b2, stream_file.read(framesize - 2)))
        # throw away the remaining stream data. Sorry I have no idea what it is
        junk_for_now = stream_file.readline()
        # convert directly to an Image instead of saving / reopening
        # thanks to SO: http://stackoverflow.com/a/12020860/377366
        image_as_file = io.BytesIO(jpeg_stripped)
        image_as_pil = Image.open(image_as_file)
        draw = ImageDraw.Draw(image_as_pil)
        draw.text((0, 0), cname, fill="white")
        draw.text((0, 10), dnow, fill="white")
        draw.text((0, 20), dnow1, fill="white")
        img_name = "Cam1-" + dte + dte1 + ".jpg"
        img_path = os.path.join(wdir, img_name)
        image_as_pil.save(img_path)


if __name__ == '__main__':
    main()

---

*下面的jpg捕获看起来不够快，这是合乎逻辑的。制作如此多的http请求对任何事情都会很慢。

from datetime import datetime
import io
import threading
import os
import time

import urllib2

from PIL import ImageFont
from PIL import Image
from PIL import ImageDraw


wdir = "workdir"


def looper(time_count, loop_name):
    start = time.time()
    end = start + time_count
    font = ImageFont.truetype("/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans.ttf", 10)
    while time.time() <= end:
        now = datetime.now()
        dte = str(now.day) + "-" + str(now.month) + "-" + str(now.year)
        dte1 = str(now.hour) + "-" + str(now.minute) + "-" + str(now.second) + "." + str(now.microsecond)
        cname = "Cam1-"
        dnow = """Date: %s """ % dte
        dnow1 = """Time: %s""" % dte1
        image = urllib2.urlopen('http://(ip address)/snapshot.cgi?user=uname&pwd=password').read()
        # convert directly to an Image instead of saving / reopening
        # thanks to SO: http://stackoverflow.com/a/12020860/377366
        image_as_file = io.BytesIO(image)
        image_as_pil = Image.open(image_as_file)
        draw = ImageDraw.Draw(image_as_pil)
        draw_text = "\n".join((cname, dnow, dnow1))
        draw.text((0, 0), draw_text, fill="white", font=font)
        #draw.text((0, 0), cname, fill="white", font=font)
        #draw.text((0, 10), dnow, fill="white", font=font)
        #draw.text((0, 20), dnow1, fill="white", font=font)
        img_name = "Cam1-" + dte + dte1 + "(" + loop_name + ").jpg"
        img_path = os.path.join(wdir, img_name)
        image_as_pil.save(img_path)


if __name__ == '__main__':
    time_count = 5
    threads = list()
    for i in range(2):
        name = str(i)
        t = threading.Thread(target=looper, args=(time_count, name))
        threads.append(p)
        t.start()
    for t in threads:
        t.join()

Answer 2

您获得的实施速度并不差。

你正在写大约每秒4.5帧（fps），而zoneminder正在写出近10 fps。下面是您的流程图，其中包含一些评论以加快速度

1. 您正在阅读网址缓冲区（网络延迟），
2. 然后写入图像（磁盘延迟1）（您可能不需要将图像写入磁盘 - 考虑将其直接传递给您的img类）
3. 读取图像（磁盘延迟2）
4. 然后使用字体，文本框等操作图像...（3图像绘制） - 你可以用换行符构建一个字符串，这样你只能调用draw.text函数吗？
5. 编写输出图像（磁盘延迟3）

Answer 3

有几件事可能会有所帮助。

• 将字体打开从函数提升到主代码，然后传入字体对象（打开字体可能是非常重要的，通过这样做，你没有采取每个图像的时间点击;你永远不会修改字体，所以共享相同的字体对象应该没问题。

• 您可以废弃包含以下三行的两条：

  draw = ImageDraw.Draw（img）