Opencv 录制多路 camera

前言

最近在写个小需求，利用opencv录制多路usb摄像头数据，并将拍摄视频拼接显示在同一个窗口。

思路

挺简单的，就是通过cv2.VideoCapture获取/dev/video*的信息，获取每个摄像头的frame后，通过numpy的hstack和vstack将两帧拼接起来。
代码如下：

import cv2
import numpy as np

# 0,2,4代表/dev/video后缀
videoFront = cv2.VideoCapture(0)
videoLeft = cv2.VideoCapture(2)
videoRight = cv2.VideoCapture(4)

width = (int(videoFront.get(cv2.CAP_PROP_FRAME_WIDTH)))
height = (int(videoFront.get(cv2.CAP_PROP_FRAME_HEIGHT)))

# 设置保存视频的宽高、帧率、格式
sz = (width*2, height*2)
fps = 30
fourcc = cv2.VideoWriter_fourcc('m', 'p', '4', 'v')
vout = cv2.VideoWriter()
vout.open('./output.mp4', fourcc, fps, sz, True)
write_ok = False

# while (videoLeft.isOpened() and videoRight.isOpened()):
while (True):
    retFront, frameFront = videoFront.read()
    retLeft, frameLeft = videoLeft.read()
    retRight, frameRight = videoRight.read()
    if(retFront and retLeft and retRight):
        frameFront = cv2.resize(frameFront, (width, height), interpolation=cv2.INTER_CUBIC)
        frameUp = np.hstack((frameFront, frameFront))

        frameLeft = cv2.resize(frameLeft, (width, height), interpolation=cv2.INTER_CUBIC)
        frameRight = cv2.resize(frameRight, (width, height), interpolation=cv2.INTER_CUBIC)
        frameDown = np.hstack((frameLeft, frameRight))

        frame = np.vstack((frameUp, frameDown))

        if write_ok:
            print("saving video...")
            vout.write(frame)
        cv2.imshow('frame', frame)

    key = cv2.waitKey(1) & 0xFF
    if key == ord("w"):
        write_ok = write_ok is not True
    if key == ord("q"):
        break

videoLeft.release()
videoRight.release()