★ ?????????????? 歡迎閱讀 【AI浩】 的博客???? 閱讀完畢，可以動動小手贊一下???? 發(fā)現(xiàn)錯誤，直接評論區(qū)中指正吧???? 這是一篇網(wǎng)絡(luò)攝像頭拉流方法總結(jié)的文章??”

摘要??

網(wǎng)絡(luò)攝像頭拉流是獲取圖片數(shù)據(jù)常用的方法，本文總結(jié)了幾種從網(wǎng)絡(luò)攝像頭拉流的方法。

1、直接使用OpenCV??

??直接使用opencv的CV2.VideoCapture直接讀取rtsp視頻流，但是這樣做的缺點是延遲嚴重、出現(xiàn)掉幀、花屏現(xiàn)象等，原因在于opencv自己有一個緩存，每次會順序從自己的緩存中讀取，而不是直接讀取最新幀。 代碼如下：

import?CV2
import?datetime
def?time_str(fmt=None):
????if?fmt?is?None:
????????fmt?=?'%Y_%m_%d_%H_%M_%S'
????return?datetime.datetime.today().strftime(fmt)

user_name,?user_pwd?=?"admin",?"1234"
ca_ip="192.168.1.100"
channel=2
cap?=?CV2.VideoCapture("rtsp://%s:%s@%s//Streaming/Channels/%d"?\
???????????????????????????%?(user_name,?user_pwd,?ca_ip,?channel))
if?cap.isOpened():
????print("Opened")
while?cap.isOpened():
????????ret,?frame?=?cap.read()
????????CV2.imwrite("opencv_"+time_str()?+?".jpg",?frame)


2、使用ffmpeg??

??FFmpeg是一套強大的視頻、音頻處理程序，也是很多視頻處理軟件的基礎(chǔ) 。但是FFmpeg的命令行使用起來有一定的學(xué)習(xí)成本。而ffmpeg-python就是解決FFmpeg學(xué)習(xí)成本的問題，讓開發(fā)者使用python就可以調(diào)用FFmpeg的功能，既減少了學(xué)習(xí)成本，也增加了代碼的可讀性。

github地址：https://github.com/kkroening/ffmpeg-python

2.1、安裝方法 ??

2.1.1、安裝ffmpeg-python ??

??ffmpeg-python可以通過典型的 pip 安裝獲取最新版本（注意：是ffmpeg-python，不要寫成了python-ffmpeg）：

pip?install?ffmpeg-python


或者可以從本地克隆和安裝源：

git?clone?git@github.com:kkroening/ffmpeg-python.git
pip?install?-e?./ffmpeg-python


2.1.2、安裝FFmpeg ??

??使用該庫，需要自行安裝FFmpeg，如果電腦已經(jīng)安裝了，可以忽略本步驟。這里推薦直接使用conda進行安裝，可以省下很多麻煩，其他的安裝方式自行百度。

conda?install?ffmpeg


2.2、代碼實現(xiàn)??

??使用ffmpeg讀取rtsp流并轉(zhuǎn)換成numpy array，并使用CV2.imwrite保存。


import?ffmpeg
import?numpy?as?np
import?CV2
import?datetime

def?main(source):
????args?=?{
????????"rtsp_transport":?"tcp",
????????"fflags":?"nobuffer",
????????"flags":?"low_delay"
????}????#?添加參數(shù)
????probe?=?ffmpeg.probe(source)
????cap_info?=?next(x?for?x?in?probe['streams']?if?x['codec_type']?==?'video')
????print("fps:?{}".format(cap_info['r_frame_rate']))
????width?=?cap_info['width']???????????#?獲取視頻流的寬度
????height?=?cap_info['height']?????????#?獲取視頻流的高度
????up,?down?=?str(cap_info['r_frame_rate']).split('/')
????fps?=?eval(up)?/?eval(down)
????print("fps:?{}".format(fps))????#?讀取可能會出錯錯誤
????process1?=?(
????????ffmpeg
????????.input(source,?**args)
????????.output('pipe:',?format='rawvideo',?pix_fmt='rgb24')
????????.overwrite_output()
????????.run_async(pipe_stdout=True)
????)
????while?True:
????????in_bytes?=?process1.stdout.read(width?*?height?*?3)?????#?讀取圖片
????????if?not?in_bytes:
????????????break
????????#?轉(zhuǎn)成ndarray
????????in_frame?=?(
????????????np
????????????.frombuffer(in_bytes,?np.uint8)
????????????.reshape([height,?width,?3])
????????)
????????frame?=?CV2.cvtColor(in_frame,?CV2.COLOR_RGB2BGR)??#?轉(zhuǎn)成BGR
????????#?CV2.imshow(time_str(),?frame)
????????CV2.imwrite(time_str()+".jpg",?frame)
????????#?if?CV2.waitKey(1)?==?ord('q'):
????????#?????break
????process1.kill()?????????????#?關(guān)閉

def?time_str(fmt=None):
????if?fmt?is?None:
????????fmt?=?'%Y_%m_%d_%H_%M_%S'
????return?datetime.datetime.today().strftime(fmt)

if?__name__?==?"__main__":
????#?rtsp流需要換成自己的
????user_name,?user_pwd?=?"admin",?"1234"
????ca_ip?=?"192.168.1.168"
????channel?=?2
????alhua_rtsp="rtsp://%s:%s@%s//Streaming/Channels/%d"?\
???????????????????????????%?(user_name,?user_pwd,?ca_ip,?channel)

????main(alhua_rtsp)


3、多線程的方式讀取圖片??

??采用多線程的方式，新開一個線程，利用變量、隊列等方式保存最新幀，使得每次都讀取最新幀，而不是opencv自己緩存中的順序幀，不會延遲，不會花屏了，代碼如下：

import?CV2
import?threading
import?sys
import??datetime
def?time_str(fmt=None):
????if?fmt?is?None:
????????fmt?=?'%Y_%m_%d_%H_%M_%S'
????return?datetime.datetime.today().strftime(fmt)

class?RTSCapture(CV2.VideoCapture):
????_cur_frame?=?None
????_reading?=?False
????schemes?=?["rtsp://","rtmp://"]
????@staticmethod
????def?create(url,?*schemes):
????????rtscap?=?RTSCapture(url)
????????rtscap.frame_receiver?=?threading.Thread(target=rtscap.recv_frame,?daemon=True)
????????rtscap.schemes.extend(schemes)
????????if?isinstance(url,?str)?and?url.startswith(tuple(rtscap.schemes)):
????????????rtscap._reading?=?True
????????elif?isinstance(url,?int):
????????????pass
????????return?rtscap

????def?isStarted(self):
????????ok?=?self.isOpened()
????????if?ok?and?self._reading:
????????????ok?=?self.frame_receiver.is_alive()
????????return?ok

????def?recv_frame(self):
????????while?self._reading?and?self.isOpened():
????????????ok,?frame?=?self.read()
????????????if?not?ok:?break
????????????self._cur_frame?=?frame
????????self._reading?=?False

????def?read2(self):
????????frame?=?self._cur_frame
????????self._cur_frame?=?None
????????return?frame?is?not?None,?frame

????def?start_read(self):
????????self.frame_receiver.start()
????????self.read_latest_frame?=?self.read2?if?self._reading?else?self.read

????def?stop_read(self):
????????self._reading?=?False
????????if?self.frame_receiver.is_alive():?self.frame_receiver.join()


if?__name__?==?'__main__':
????user_name,?user_pwd?=?"admin",?"1234"
????ca_ip?=?"192.168.1.100"
????channel?=?2
????alhua_rtsp="rtsp://%s:%s@%s//Streaming/Channels/%d"?\
???????????????????????????%?(user_name,?user_pwd,?ca_ip,?channel)

????rtscap?=?RTSCapture.create(alhua_rtsp)
????rtscap.start_read()

????while?rtscap.isStarted():
????????ok,?frame?=?rtscap.read_latest_frame()
????????#?if?CV2.waitKey(100)?&?0xFF?==?ord('q'):
????????#?????break
????????if?not?ok:
????????????continue


????????#?inhere
????????#?CV2.imshow(time_str(),?frame)
????????CV2.imwrite(time_str()?+?".jpg",?frame)


????rtscap.stop_read()
????rtscap.release()
????CV2.destroyAllWindows()


運行結(jié)果：

4、多進程的方式拉流??

??使用Python3自帶的多進程模塊，創(chuàng)建一個隊列，進程A從通過rtsp協(xié)議從視頻流中讀取出每一幀，并放入隊列中，進程B從隊列中將圖片取出，處理后進行顯示。進程A如果發(fā)現(xiàn)隊列里有兩張圖片（證明進程B的讀取速度跟不上進程A），那么進程A主動將隊列里面的舊圖片刪掉，換上新圖片。通過多線程的方法：

代碼如下：

import?CV2
import?multiprocessing?as?mp
import?time
import?datetime


def?time_str(fmt=None):
????if?fmt?is?None:
????????fmt?=?'%Y_%m_%d_%H_%M_%S'
????return?datetime.datetime.today().strftime(fmt)

def?image_put(q,?user,?pwd,?ip,?channel=1):
????cap?=?CV2.VideoCapture("rtsp://%s:%s@%s//Streaming/Channels/%d"?%?(user,?pwd,?ip,?channel))
????if?cap.isOpened():
????????print('HIKVISION')
????else:
????????cap?=?CV2.VideoCapture("rtsp://%s:%s@%s/cam/realmonitor?channel=%d&subtype=0"?%?(user,?pwd,?ip,?channel))
????????print('DaHua')

????while?True:
????????q.put(cap.read()[1])
????????q.get()?if?q.qsize()?>?1?else?time.sleep(0.01)


def?image_get(q,?window_name):
????#?CV2.namedWindow(window_name,?flags=CV2.WINDOW_FREERATIO)
????while?True:
????????frame?=?q.get()
????????#?CV2.imshow(window_name,?frame)
????????#?CV2.waitKey(1)
????????CV2.imwrite("opencv_"+time_str()?+?".jpg",?frame)
????????CV2.waitKey(1)

def?run_single_camera():
????user_name,?user_pwd,?camera_ip?=?"admin",?"admin123456",?"192.168.35.121"

????mp.set_start_method(method='spawn')??#?init
????queue?=?mp.Queue(maxsize=2)
????processes?=?[mp.Process(target=image_put,?args=(queue,?user_name,?user_pwd,?camera_ip)),
?????????????????mp.Process(target=image_get,?args=(queue,?camera_ip))]

????[process.start()?for?process?in?processes]
????[process.join()?for?process?in?processes]

def?run_multi_camera():
????#?user_name,?user_pwd?=?"admin",?"password"
????user_name,?user_pwd?=?"admin",?"1234"
????camera_ip_l?=?[
????????"192.168.1.XX3",??#?ipv4
????????"192.168.1.XX2",
????????"192.168.1.XX1",
????]

????mp.set_start_method(method='spawn')??#?init
????queues?=?[mp.Queue(maxsize=90)?for?_?in?camera_ip_l]

????processes?=?[]
????for?queue,?camera_ip?in?zip(queues,?camera_ip_l):
????????processes.append(mp.Process(target=image_put,?args=(queue,?user_name,?user_pwd,?camera_ip)))
????????processes.append(mp.Process(target=image_get,?args=(queue,?camera_ip)))

????for?process?in?processes:
????????process.daemon?=?True
????????process.start()
????for?process?in?processes:
????????process.join()


if?__name__?==?'__main__':
????#?run_single_camera()
????run_multi_camera()
????pass


參考文章：https://blog.csdn.net/ljx1400052550/article/details/106987943