从父进程到子进程的网络摄像头流

Question

我想使用网络摄像头通过命名的 pipe.The 父进程向子进程发送视频帧流，父进程显示发送的帧，而子进程显示接收的 frames.I 正在使用openCV 2.4.12 用于访问和显示 UBuntu 14.04.However 上的视频帧，它只发送一帧并且 freezes.I 无法找出导致 problem.This 代码工作正常的原因如果我发送单张图片，但在尝试发送流时卡在第一帧。

代码如下：

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
using namespace cv;
using namespace std;


void  ChildProcess(void);                /* child process prototype  */
void  ParentProcess(void);               /* parent process prototype */

int  main()
 {

 pid_t  pid;

 pid = fork();
 if (pid == 0)
      ChildProcess();
 else
    ParentProcess();

 }

void  ChildProcess(void)
{

int fd2 = open("/home/eelab/vidpipe",O_RDONLY);

for(;;)
{
int rows = 480;
int cols = 640;
int nchan = 3;
int totalbytes = rows*cols*nchan;
int buflen = cols*nchan;
int ret;
//int fd1 = open("/dev/xillybus_read_32",O_RDONLY);

uchar buf[buflen];
uchar datarray[totalbytes];
Mat img(rows,cols,CV_8UC3);

int j;
int k = 0;
int num = totalbytes/buflen;
int bread = 0;
while(bread<totalbytes)
{

    ret=read(fd2,buf,buflen);
    for ( j = 0 ; j<= (ret-1);j++ )
    {
        datarray[j+k] = buf[j];

    }
        k = k+ret;
    bread = bread+ret;
}

img.data = datarray;

namedWindow( "Received image", WINDOW_AUTOSIZE );
imshow( "Received image", img );
waitKey(0);
}
close(fd2);
}

void  ParentProcess(void)
{

int check;
int fd;
int totalbytes;
int buflen;
int count = 0;
fd = open("/home/eelab/vidpipe",O_WRONLY);
if (fd < 1)
{
    perror("open error");
}

VideoCapture cap(0);

for(;;)
{
    Mat frame;
    cap >> frame;


totalbytes = frame.total()*frame.elemSize();
buflen = (frame.cols*3);

uchar *framepointer = frame.data;



 int bwritten = 0;
 int ret;
 uchar* buf;
 buf = framepointer;
 int num = totalbytes/buflen;
 while(bwritten<totalbytes)
 {
   ret = write(fd,buf,buflen);
   write(fd,NULL,0);
   buf = buf + ret;
   bwritten = bwritten+ret;
  }



    namedWindow( "Sent image", WINDOW_AUTOSIZE );
    imshow( "Sent image", frame );
    waitKey(0);

  }

  close(fd);

  }

请帮忙，我怎样才能获得连续流？

Answer 1

waitKey(0); 将阻塞进程，直到按下某个键。如果您更改为 waitKey(1);，它将在 >= 1 ms 之后自动进行。如果这不够快（例如，您的 fps 非常高），您应该切换到不同的 GUI 库（例如 Qt）。

从父进程到子进程的网络摄像头流

Webcam stream from parent process to child process

c

c++

linux

opencv

systems-programming