前言
网络摄像头的视频流解析直接使用通过http的Mjpeg是具有边界帧信息的multipart / x-mixed-replace，而jpeg数据只是以二进制形式发送。因此，实际上不需要关心HTTP协议标头。所有jpeg帧均以marker开头，0xff 0xd8并以结尾0xff 0xd9。因此，上面的代码从http流中提取了此类帧，并将其一一解码。像下面
...(http)
0xff 0xd8 —|
[jpeg data] |–this part is extracted and decoded
0xff 0xd9 —|
...(http)
0xff 0xd8 —|
[jpeg data] |–this part is extracted and decoded
0xff 0xd9 —|
...(http)
如果图像的获取是从tcp网络中传输到本地进行解析需要对bytes类型数据进行解码
在使用OpenCV直接调用网络摄像头时可能会出现
Cam not found
这时候就需要下面这种办法
代码：
帧解析import cv2
cap = cv2.VideoCapture(http://localhost:8080/frame.mjpg)
while True:
ret, frame = cap.read()
print(frame)
if ret == True:
cv2.imshow(Video, frame)
if cv2.waitKey(1) == 27:
exit(0)
视频流解析
import cv2
import requests
import numpy as np
r = requests.get(http://192.168.1.xx/mjpeg.cgi, auth=(user, password), stream=True)
if(r.status_code == 200):
bytes = bytes()
for chunk in r.iter_content(chunk_size=1024):
bytes += chunk
a = bytes.find(b\xff\xd8)
b = bytes.find(b\xff\xd9)
if a != –1 and b != –1:
jpg = bytes[a:b+2]
bytes = bytes[b+2:]
i = cv2.imdecode(np.fromstring(jpg, dtype=np.uint8), cv2.IMREAD_COLOR)
cv2.imshow(i, i)
if cv2.waitKey(1) == 27:
exit(0)
else:
print(“Received unexpected status code {}”.format(r.status_code))
以上就是python3从网络摄像机解析mjpeg http流的示例的详细内容。
