如何用python写迈德威视的取流

Question

买了迈德威视的工业摄像头，现在不知道用python-opencv写迈德威视的取流，官方的demo能运行跑出来，能调用摄像头，但是要是用自己的代码就调不出摄像头。
这是官方demo

#coding=utf-8
import cv2
import numpy as np
import mvsdk
import time

class App(object):
def init(self):
super(App, self).init()
self.pFrameBuffer = 0
self.quit = False

def main(self):
    # 枚举相机
    DevList = mvsdk.CameraEnumerateDevice()
    nDev = len(DevList)
    if nDev < 1:
        print("No camera was found!")
        return

    for i, DevInfo in enumerate(DevList):
        print("{}: {} {}".format(i, DevInfo.GetFriendlyName(), DevInfo.GetPortType()))
    i = 0 if nDev == 1 else int(input("Select camera: "))
    DevInfo = DevList[i]
    print(DevInfo)

    # 打开相机
    hCamera = 0
    try:
        hCamera = mvsdk.CameraInit(DevInfo, -1, -1)
    except mvsdk.CameraException as e:
        print("CameraInit Failed({}): {}".format(e.error_code, e.message) )
        return

    # 获取相机特性描述
    cap = mvsdk.CameraGetCapability(hCamera)

    # 判断是黑白相机还是彩色相机
    monoCamera = (cap.sIspCapacity.bMonoSensor != 0)

    # 黑白相机让ISP直接输出MONO数据，而不是扩展成R=G=B的24位灰度
    if monoCamera:
        mvsdk.CameraSetIspOutFormat(hCamera, mvsdk.CAMERA_MEDIA_TYPE_MONO8)
    else:
        mvsdk.CameraSetIspOutFormat(hCamera, mvsdk.CAMERA_MEDIA_TYPE_BGR8)

    # 相机模式切换成连续采集
    mvsdk.CameraSetTriggerMode(hCamera, 0)

    # 手动曝光，曝光时间30ms
    mvsdk.CameraSetAeState(hCamera, 0)
    mvsdk.CameraSetExposureTime(hCamera, 30 * 1000)

    # 让SDK内部取图线程开始工作
    mvsdk.CameraPlay(hCamera)

    # 计算RGB buffer所需的大小，这里直接按照相机的最大分辨率来分配
    FrameBufferSize = cap.sResolutionRange.iWidthMax * cap.sResolutionRange.iHeightMax * (1 if monoCamera else 3)

    # 分配RGB buffer，用来存放ISP输出的图像
    # 备注：从相机传输到PC端的是RAW数据，在PC端通过软件ISP转为RGB数据（如果是黑白相机就不需要转换格式，但是ISP还有其它处理，所以也需要分配这个buffer）
    self.pFrameBuffer = mvsdk.CameraAlignMalloc(FrameBufferSize, 16)

    # 设置采集回调函数
    self.quit = False
    mvsdk.CameraSetCallbackFunction(hCamera, self.GrabCallback, 0)

    # 等待退出
    while not self.quit:
        time.sleep(0.1)

    # 关闭相机
    mvsdk.CameraUnInit(hCamera)

    # 释放帧缓存
    mvsdk.CameraAlignFree(self.pFrameBuffer)

@mvsdk.method(mvsdk.CAMERA_SNAP_PROC)
def GrabCallback(self, hCamera, pRawData, pFrameHead, pContext):
    FrameHead = pFrameHead[0]
    pFrameBuffer = self.pFrameBuffer

    mvsdk.CameraImageProcess(hCamera, pRawData, pFrameBuffer, FrameHead)
    mvsdk.CameraReleaseImageBuffer(hCamera, pRawData)
    
    # 此时图片已经存储在pFrameBuffer中，对于彩色相机pFrameBuffer=RGB数据，黑白相机pFrameBuffer=8位灰度数据
    # 把pFrameBuffer转换成opencv的图像格式以进行后续算法处理
    frame_data = (mvsdk.c_ubyte * FrameHead.uBytes).from_address(pFrameBuffer)
    frame = np.frombuffer(frame_data, dtype=np.uint8)
    frame = frame.reshape((FrameHead.iHeight, FrameHead.iWidth, 1 if FrameHead.uiMediaType == mvsdk.CAMERA_MEDIA_TYPE_MONO8 else 3) )

    frame = cv2.resize(frame, (640,480), interpolation = cv2.INTER_LINEAR)
    cv2.imshow("Press q to end", frame)
    if (cv2.waitKey(1) & 0xFF) == ord('q'):
        self.quit = True

def main():
try:
app = App()
app.main()
finally:
cv2.destroyAllWindows()

main()

Answer 1

如果是自己代码不通建议贴一下自己的代码，才能看是什么问题