singleCamD

Linux环境下使用V4L2+opencv以MJPEG格式读取USB摄像头并实时显示的源代码

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

uchar *buffer;

#define IMAGEWIDTH 640
#define IMAGEHEIGHT 480

#define TRUE 1
#define FALSE 0

#define FILE_VIDEO1 “/dev/video1“

static int fd;
struct v4l2_streamparm setfps;
struct v4l2_capability cap;
struct v4l2_fmtdesc fmtdesc;
struct v4l2_format fmtfmtack;
struct v4l2_requestbuffers req;
struct v4l2_buffer buf;
enum   v4l2_buf_type type;

int init_v4l2（void）;
int v4l2_grab（void）;



int main（）
{
        printf（“first~~\n“）;
        if（init_v4l2（） == FALSE）{
            printf（“Init fail~~\n“）;
            exit（1）;
        }
        printf（“second~~\n“）;
        if（v4l2_grab（） == FALSE）{
            printf（“grab fail~~\n“）;
            exit（2）;
        }
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        printf（“third~~\n“）;
        cvNamedWindow（“one“CV_WINDOW_AUTOSIZE）;
        IplImage* img;
        CvMat cvmat;
        int i = 100;
        double t;
        while（1）{
                t = （double）cvGetTickCount（）;
                ioctl（fdVIDIOC_DQBUF&buf）;
                buf.index = 0;
                cvmat = cvMat（IMAGEHEIGHTIMAGEWIDTHCV_8UC3（void*）buffer）;//CV_8UC3
                //t = （double）cvGetTickCount（）;
                img = cvDecodeImage（&cvmat1）;
                //t=（double）cvGetTickCount（）-t;
                //printf（“used time is %gms\n“（t/（cvGetTickFrequency（）*1000）））;
                if（!img）    printf（“No img\n“）;
                cvShowImage（“one“img）;
                cvReleaseImage（&img）;
                ioctl（fdVIDIOC_QBUF&buf）;
                if（（cvWaitKey（1）&255） == 27）    exit（0）;
                t=（double）cvGetTickCount（）-t;
                printf（“used time is %gms\n“（t/（cvGetTickFrequency（）*1000）））;
        }

        ioctl（fdVIDIOC_STREAMOFF&type）;
        return 0;
}

int init_v4l2（void）{
        if （（fd = open（FILE_VIDEO1 O_RDWR）） == -1）{
            printf（“Opening video device error\n“）;
            return FALSE;
        }
        if （ioctl（fd VIDIOC_QUERYCAP &cap） == -1）{
                printf（“unable Querying Capabilities\n“）;
                return FALSE;
        }
        else
/*
        {
        printf（ “Driver Caps:\n“
                “  Driver: \“%s\“\n“
                “  Card: \“%s\“\n“
                “  Bus: \“%s\“\n“
                “  Version: %d\n“
                “  Capabilities: %x\n“
                cap.driver
                cap.card
                cap.bus_info
                cap.version
                cap.capabilities）;

        }

        if（（cap.capabilities & V4L2_CAP_VIDEO_CAPTURE） == V4L2_CAP_VIDEO_CAPTURE）{
            printf（“Camera device %s: support capture\n“FILE_VIDEO1）;
        }
        if（（cap.capabilities & V4L2_CAP_STREAM

 属性            大小     日期    时间   名称
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     文件        248  2015-08-12 16:19  singleCamD\singleCamD.pro

     文件      18135  2015-08-12 20:59  singleCamD\singleCamD.pro.user

     文件       6306  2015-08-12 20:46  singleCamD\main.cpp

     目录          0  2015-08-12 20:59  singleCamD

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