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V4L2 camera 驱动 capture测试程序

落鹤生 发布于 2012-08-27 09:33 点击:次 
这个测试程序是根据vivi驱动hard code的, 并不一定适合其他的camera驱动.比如,我手头上的logitech stv06xx usb camera, 因为不支持640x480模式,参见代码59 60行,
TAG:

在网上找了一个测试程序, 看了看,是根据capture.c修改的。测试步骤如下

1. gcc -o capture_image capture_image.c

2. ctrl+alt+f1 切换到ubuntu的控制台,切换到控制台模式是因为在图形模式下看不到测试图形,这可能和framebuffer的设置有关

3. sudo modprobe vivi

4. sudo ./capture_image -d /dev/video0

 

这时可以看到在屏幕左上角有一个640x480大小窗口,内容是彩色条格,彩色条格不停的移动,持续时间5秒

 

在ubuntu下还可以使用cheese测试

1.  sudo apt-get install cheese

2. sudo modprobe vivi

2. 启动 cheese后,就可以看到滚动的彩色条格


附上测试程序

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <getopt.h>  
#include <fcntl.h>  
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <asm/types.h>
#include <linux/videodev2.h>
#include <linux/fb.h>
#define CLEAR(x) memset (&(x), 0, sizeof (x))
 
struct buffer {
    void * start;
    size_t length;
};
 
static char * dev_name = NULL;
static int fd = -1;
struct buffer * buffers = NULL;
static unsigned int n_buffers = 0;
static int time_in_sec_capture=5;
static int fbfd = -1;
static struct fb_var_screeninfo vinfo;
static struct fb_fix_screeninfo finfo;
static char *fbp=NULL;
static long screensize=0;
 
static void errno_exit (const char * s)
{
    fprintf (stderr, "%s error %d, %s/n",s, errno, strerror (errno));
    exit (EXIT_FAILURE);
}
 
static int xioctl (int fd,int request,void * arg)
{
    int r;
    do r = ioctl (fd, request, arg);
    while (-1 == r && EINTR == errno);
    return r;
}
 
inline int clip(int value, int min, int max) {
    return (value > max ? max : value < min ? min : value);
  }
 
static void process_image (const void * p){
 
    
    //ConvertYUVToRGB32
    1;
    unsigned char* in=(char*)p;
    int width=640;
    int height=480;
    int istride=1280;
    int x,y,j;
    int y0,u,y1,v,r,g,b;
    long location=0;
 
    for ( y = 100; y < height + 100; ++y) {
        for (j = 0, x=100; j < width * 2 ; j += 4,x +=2) {
          location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) +
            (y+vinfo.yoffset) * finfo.line_length;
            
          y0 = in[j];
          u = in[j + 1] - 128;                
          y1 = in[j + 2];        
          v = in[j + 3] - 128;        
 
          r = (298 * y0 + 409 * v + 128) >> 8;
          g = (298 * y0 - 100 * u - 208 * v + 128) >> 8;
          b = (298 * y0 + 516 * u + 128) >> 8;
        
          fbp[ location + 0] = clip(b, 0, 255);
          fbp[ location + 1] = clip(g, 0, 255);
          fbp[ location + 2] = clip(r, 0, 255);    
          fbp[ location + 3] = 255;    
 
          r = (298 * y1 + 409 * v + 128) >> 8;
          g = (298 * y1 - 100 * u - 208 * v + 128) >> 8;
          b = (298 * y1 + 516 * u + 128) >> 8;
 
           fbp[ location + 4] = clip(b, 0, 255);
          fbp[ location + 5] = clip(g, 0, 255);
          fbp[ location + 6] = clip(r, 0, 255);    
          fbp[ location + 7] = 255;    
          }
        in +=istride;
       }
}
 
static int read_frame (void)
{
    struct v4l2_buffer buf;
    unsigned int i;
 
    CLEAR (buf);
    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
 
    if (-1 == xioctl (fd, VIDIOC_DQBUF, &buf)) {
        switch (errno) {
        case EAGAIN:
        return 0;
        case EIO:    
 
        
 
        default:
            errno_exit ("VIDIOC_DQBUF");
        }
    }
 
    assert (buf.index < n_buffers);
    printf("v4l2_pix_format->field(%d)/n", buf.field);
    //assert (buf.field ==V4L2_FIELD_NONE);
    process_image (buffers[buf.index].start);
    if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
        errno_exit ("VIDIOC_QBUF");
 
    return 1;
}
 
static void run (void)
{
    unsigned int count;
    int frames;
    frames = 30 * time_in_sec_capture;
 
    while (frames-- > 0) {
        for (;;) {
            fd_set fds;
            struct timeval tv;
            int r;
            FD_ZERO (&fds);
            FD_SET (fd, &fds);
 
            
            tv.tv_sec = 2;
            tv.tv_usec = 0;
 
            r = select (fd + 1, &fds, NULL, NULL, &tv);
 
            if (-1 == r) {
                if (EINTR == errno)
                    continue;
                errno_exit ("select");
            }
 
            if (0 == r) {
                fprintf (stderr, "select timeout/n");
                exit (EXIT_FAILURE);
            }
 
            if (read_frame ())
                break;
            
            }
    }
}
 
static void stop_capturing (void)
{
    enum v4l2_buf_type type;
 
    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if (-1 == xioctl (fd, VIDIOC_STREAMOFF, &type))
        errno_exit ("VIDIOC_STREAMOFF");
}
 
static void start_capturing (void)
{
    unsigned int i;
    enum v4l2_buf_type type;
 
    for (i = 0; i < n_buffers; ++i) {
        struct v4l2_buffer buf;
        CLEAR (buf);
 
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = i;
 
        if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
            errno_exit ("VIDIOC_QBUF");
        }
 
    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 
    if (-1 == xioctl (fd, VIDIOC_STREAMON, &type))
        errno_exit ("VIDIOC_STREAMON");
    
}
 
static void uninit_device (void)
{
    unsigned int i;
 
    for (i = 0; i < n_buffers; ++i)
        if (-1 == munmap (buffers[i].start, buffers[i].length))
            errno_exit ("munmap");
    
    if (-1 == munmap(fbp, screensize)) {
          printf(" Error: framebuffer device munmap() failed./n");
          exit (EXIT_FAILURE) ;
        }    
    free (buffers);
}
 
 
static void init_mmap (void)
{
    struct v4l2_requestbuffers req;
 
    //mmap framebuffer
        fbp = (char *)mmap(NULL,screensize,PROT_READ | PROT_WRITE,MAP_SHARED ,fbfd, 0);
        if ((int)fbp == -1) {
            printf("Error: failed to map framebuffer device to memory./n");
            exit (EXIT_FAILURE) ;
        }
    memset(fbp, 0, screensize);
    CLEAR (req);
 
    req.count = 4;
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req.memory = V4L2_MEMORY_MMAP;
 
    if (-1 == xioctl (fd, VIDIOC_REQBUFS, &req)) {
        if (EINVAL == errno) {
            fprintf (stderr, "%s does not support memory mapping/n", dev_name);
            exit (EXIT_FAILURE);
        } else {
            errno_exit ("VIDIOC_REQBUFS");
        }
    }
 
    if (req.count < 4) {    //if (req.count < 2)
        fprintf (stderr, "Insufficient buffer memory on %s/n",dev_name);
        exit (EXIT_FAILURE);
    }
 
    buffers = calloc (req.count, sizeof (*buffers));
 
    if (!buffers) {
        fprintf (stderr, "Out of memory/n");
        exit (EXIT_FAILURE);
    }
 
    for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
        struct v4l2_buffer buf;
 
        CLEAR (buf);
 
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = n_buffers;
 
        if (-1 == xioctl (fd, VIDIOC_QUERYBUF, &buf))
            errno_exit ("VIDIOC_QUERYBUF");
 
        buffers[n_buffers].length = buf.length;
        buffers[n_buffers].start =mmap (NULL,buf.length,PROT_READ | PROT_WRITE ,MAP_SHARED,fd, buf.m.offset);
 
        if (MAP_FAILED == buffers[n_buffers].start)
            errno_exit ("mmap");
    }
 
}
 
 
 
static void init_device (void)
{
    struct v4l2_capability cap;
    struct v4l2_cropcap cropcap;
    struct v4l2_crop crop;
    struct v4l2_format fmt;
    unsigned int min;
 
 
    // Get fixed screen information
      if (-1==xioctl(fbfd, FBIOGET_FSCREENINFO, &finfo)) {
            printf("Error reading fixed information./n");
            exit (EXIT_FAILURE);
        }
 
        // Get variable screen information
     if (-1==xioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo)) {
            printf("Error reading variable information./n");
            exit (EXIT_FAILURE);
       }
    screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8;
 
 
    if (-1 == xioctl (fd, VIDIOC_QUERYCAP, ∩)) {
        if (EINVAL == errno) {
            fprintf (stderr, "%s is no V4L2 device/n",dev_name);
            exit (EXIT_FAILURE);
        } else {
            errno_exit ("VIDIOC_QUERYCAP");
          }
    }
 
    if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
        fprintf (stderr, "%s is no video capture device/n",dev_name);
        exit (EXIT_FAILURE);
    }
 
    if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
        fprintf (stderr, "%s does not support streaming i/o/n",dev_name);
        exit (EXIT_FAILURE);
    }
 
    
 
    CLEAR (cropcap);
 
    cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 
    if (0 == xioctl (fd, VIDIOC_CROPCAP, &cropcap)) {
        crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        crop.c = cropcap.defrect;
 
        if (-1 == xioctl (fd, VIDIOC_S_CROP, &crop)) {
            switch (errno) {
            case EINVAL:    
            break;
            default:
            break;
            }
        }
    }else {     }
 
    CLEAR (fmt);
 
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = 640;  
    fmt.fmt.pix.height = 480;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
 
    if (-1 == xioctl (fd, VIDIOC_S_FMT, &fmt))
        errno_exit ("VIDIOC_S_FMT");
 
    init_mmap ();
 
}
 
static void close_device (void)
{
    if (-1 == close (fd))
    errno_exit ("close");
    fd = -1;
    close(fbfd);
}
 
static void open_device (void)
{
    struct stat st;  
 
    if (-1 == stat (dev_name, &st)) {
    fprintf (stderr, "Cannot identify '%s': %d, %s/n",dev_name, errno, strerror (errno));
    exit (EXIT_FAILURE);
    }
 
    if (!S_ISCHR (st.st_mode)) {
    fprintf (stderr, "%s is no device/n", dev_name);
    exit (EXIT_FAILURE);
    }
 
    //open framebuffer
        fbfd = open("/dev/fb0", O_RDWR);
        if (fbfd==-1) {
            printf("Error: cannot open framebuffer device./n");
            exit (EXIT_FAILURE);
        }
 
    //open camera
    fd = open (dev_name, O_RDWR| O_NONBLOCK, 0);
 
    if (-1 == fd) {
    fprintf (stderr, "Cannot open '%s': %d, %s/n",dev_name, errno, strerror (errno));
    exit (EXIT_FAILURE);
    }
}
 
static void usage (FILE * fp,int argc,char ** argv)
{
fprintf (fp,
"Usage: %s [options]/n/n"
"Options:/n"
"-d | --device name Video device name [/dev/video]/n"
"-h | --help Print this message/n"
"-t | --how long will display in seconds/n"
"",
argv[0]);
}
 
static const char short_options [] = "d:ht:";
static const struct option long_options [] = {
{ "device", required_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{ "time", no_argument, NULL, 't' },
{ 0, 0, 0, 0 }
};
 
int main (int argc,char ** argv)
    {
    dev_name = "/dev/video0";
 
    for (;;)  
        {
        int index;
        int c;
 
        c = getopt_long (argc, argv,short_options, long_options,&index);
        if (-1 == c)
        break;
 
        switch (c) {
        case 0:
        break;
 
        case 'd':
        dev_name = optarg;
        break;
 
        case 'h':
        usage (stdout, argc, argv);
        exit (EXIT_SUCCESS);
        case 't':
           time_in_sec_capture = atoi(optarg);
             break;
 
        default:
        usage (stderr, argc, argv);
        exit (EXIT_FAILURE);
        }
}
 
    open_device ();
 
    init_device ();
 
    start_capturing ();
 
    run ();
 
    stop_capturing ();
 
    uninit_device ();
 
    close_device ();
 
    exit (EXIT_SUCCESS);
 
return 0;
}




这个测试程序是根据vivi驱动hard code的, 并不一定适合其他的camera驱动
比如,我手头上的logitech stv06xx usb camera, 因为不支持640x480模式,参见代码59 60行,
代码348行 if (-1 == xioctl (fd, VIDIOC_S_FMT, &fmt)) 应该是个协商的过程,
343   fmt.fmt.pix.width = 640;   
344   fmt.fmt.pix.height = 480; 
345   fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; 
346   fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; 
这几行只是应用的期望格式,驱动会根据这个格式选择一个相近的格式返回,应用最后的显示处理要根据返回的格式进行处理,即process_image要做相应修改

(kickxxx)
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本文出处:CSDN博客 作者:kickxxx 原文
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