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最近做一个视频采集,为了调试,先截了图片出来,涉及到图片的转换。调试过程花了一定的时间,现把源代码奉上,供大家参考
#include stdio.h>
#include stdlib.h>
#include unistd.h>
#include linux/videodev.h>
#include sys/ioctl.h>
#include fcntl.h>
#include linux/fb.h>
#include sys/mman.h>
#include linux/delay.h>
#include time.h>
#define ERR_FRAME_BUFFER 1
#define ERR_VIDEO_OPEN 2
#define ERR_VIDEO_GCAP 3
#define ERR_VIDEO_GPIC 4
#define ERR_VIDEO_SPIC 5
#define ERR_SYNC 6
#define ERR_FRAME_USING 7
#define ERR_GET_FRAME 8
typedef struct _fb_v4l
{
int fbfd ;
struct fb_var_screeninfo vinfo;
struct fb_fix_screeninfo finfo;
char *fbp;
int fd;
struct video_capability capability;
struct video_buffer buffer;
struct video_window window;
struct video_channel channel[8];
struct video_picture picture;
struct video_tuner tuner;
struct video_audio audio[8];
struct video_mmap mmap;
struct video_mbuf mbuf;
unsigned char *map;
int frame_current;
int frame_using[VIDEO_MAX_FRAME];
}fb_v41;
struct file_header
{
unsigned short bfType; // Picture tpye, must set to 19778
int bfSize; // The file size in bytes
int bfRev; // Reserved
int bfOffBits; // the offset from the beginning of the file to the bitmap data.
}__attribute__ ((packed));
struct info_header
{
int biSize; // info_header's size in bytes
int biWidth; // width in pixels
int biHeight;//height in pixels
short biPlanes; //the number of planes of the target device
short biBitCount; //the number of bits per pixel
int biCompression;//the type of compression
int biSizeImage; //
int biXPelsPerMeter;//usually set to zero
int biYPelsPerMeter;//usually set to zero
int biClrUsed;//the number of colors used in the bitmap
int biClrImportant;
}__attribute__ ((packed));
struct bmp_file
{
struct file_header header;
struct info_header info;
unsigned char bits[640*480*3];
}__attribute__ ((packed));
#define V4L_FILE "/dev/video0"
int get_grab_frame(fb_v41 *vd, int frame)
{
if (vd->frame_using[frame])
{
fprintf(stderr, "get_grab_frame: frame %d is already used.\n", frame);
return ERR_FRAME_USING;
}
vd->mmap.frame = frame;
if (ioctl(vd->fd, VIDIOCMCAPTURE, &(vd->mmap)) 0)
{
perror("v4l_grab_frame");
return ERR_GET_FRAME;
}
vd->frame_using[frame] = 1;
vd->frame_current = frame;
return 0;
}
int get_first_frame(fb_v41 *vd)
{
int ret;
vd->frame_current = 0;
ret = get_grab_frame( vd, 0 );
if ( ret0 )
return ret;
if (ioctl(vd->fd, VIDIOCSYNC, &(vd->frame_current)) 0)
{
perror("v4l_grab_sync");
return ERR_SYNC;
}
vd->frame_using[vd->frame_current] = 0 ;
return (0);
}
int get_next_frame(fb_v41 *vd)
{
int ret;
vd->frame_current ^= 1;
ret = get_grab_frame( vd,vd->frame_current);
if( ret 0 )
return ret;
if (ioctl(vd->fd, VIDIOCSYNC, &(vd->frame_current)) 0)
{
perror("v4l_grab_sync");
return ERR_SYNC;
}
vd->frame_using[vd->frame_current] = 0 ;
return 0;
}
unsigned char *get_frame_address(fb_v41 *vd)
{
return (vd->map + vd->mbuf.offsets[vd->frame_current]);
}
int open_video( char *fileptr,fb_v41 *vd ,int dep,int pal,int width,int height)
{
if ((vd->fd = open(fileptr, O_RDWR)) 0)
{
perror("v4l_open:");
return ERR_VIDEO_OPEN;
}
if (ioctl(vd->fd, VIDIOCGCAP, &(vd->capability)) 0)
{
perror("v4l_get_capability:");
return ERR_VIDEO_GCAP;
}
if (ioctl(vd->fd, VIDIOCGPICT, &(vd->picture)) 0)
{
perror("v4l_get_picture");
return ERR_VIDEO_GPIC;
}
vd->picture.palette = pal;
vd->picture.depth = dep;
vd->mmap.format = pal;
if (ioctl(vd->fd, VIDIOCSPICT, &(vd->picture)) 0)
{
perror("v4l_set_palette");
return ERR_VIDEO_SPIC;
}
vd->mmap.width = width;
vd->mmap.height = height;
vd->mmap.format = vd->picture.palette;
vd->frame_current = 0;
vd->frame_using[0] = 0;
vd->frame_using[1] = 0;
if (ioctl(vd->fd, VIDIOCGMBUF, &(vd->mbuf)) 0)
{
perror("v4l_get_mbuf");
return -1;
}
vd->map = mmap(0, vd->mbuf.size, PROT_READ|PROT_WRITE, MAP_SHARED, vd->fd, 0);
if ( vd->map 0)
{
perror("v4l_mmap_init:mmap");
return -1;
}
printf("The video device was opened successfully.\n");
return 0;
}
static void cvt_420p_to_rgb(int width, int height, const unsigned char *src, unsigned char *dst)
{
int r, g, b;
int rdif, gdif, bdif, y;
int yy, uu, vv;
int xoff, yoff;
int numpix = width*height;
unsigned char *pout = dst + width*height*3;
for(yoff=0; yoffheight; yoff++)
{
for(xoff=0; xoffwidth; xoff++)
{
yy = *(src+yoff*640+xoff);
uu = *(src+(yoff/2)*320+xoff/2+numpix);
vv = *(src+(yoff/2)*320+xoff/2+numpix+numpix/4);
uu -= 128;
vv -= 128;
r = yy + vv + ((vv*103)>>8);
g = yy - ((uu*88)>>8) - ((vv*183)>>8);
b = yy + uu + ((uu*198)>>8);
if(r>255) { r = 255; }
if(g>255) { g = 255; }
if(b>255) { b = 255; }
if(r0) { r = 0;}
if(g0) { g = 0;}
if(b0) { b = 0;}
*pout = (unsigned char)b;
pout--;
*pout = (unsigned char)r;
pout--;
*pout = (unsigned char)g;
pout--;
}
}
}
int main( void )
{
fb_v41 vd;
int ret,i;
int k=0;
unsigned char *imageptr;
struct bmp_file myfile;
int fd;
printf("sizeof short is %d\n", sizeof(short));
myfile.header.bfType = 19778;
myfile.header.bfSize = sizeof(struct bmp_file);
myfile.header.bfRev = 0;
myfile.header.bfOffBits = 54;
myfile.info.biSize = 0x28;
myfile.info.biWidth = 640;
myfile.info.biHeight = 480;
myfile.info.biPlanes = 1;
myfile.info.biBitCount = 24;
myfile.info.biCompression = 0;
myfile.info.biSizeImage = 0;
myfile.info.biClrUsed = 256*256*256;
myfile.info.biClrImportant = 0;
myfile.info.biXPelsPerMeter = 2048;
myfile.info.biYPelsPerMeter = 2048;
fd = open("./first.bmp", O_RDWR);
if(fd 0)
{
printf("open file error!\n");
return 0;
}
ret = open_video( V4L_FILE, &vd, 24, VIDEO_PALETTE_YUV420P, 640, 480);
if( ret )
{
printf("Open video failed!\n");
goto err;
}
printf(vd.capability.name);
printf(", Type:%d\n",vd.capability.type);
printf("Maxwidth:%d,Maxheight:%d\n",vd.capability.maxwidth ,vd.capability.maxheight);
printf("Minwidth:%d,Minheight:%d\n",vd.capability.minwidth,vd.capability.minheight);
printf("Channels:%d,Audios:%d\n",vd.capability.channels,vd.capability.audios);
for(i=0;i10;i++)
{
imageptr = (unsigned char *)get_frame_address(&vd );
if(get_next_frame( &vd ) !=0 )
{
goto err;
}
printf("i = %d\n", i);
}
cvt_420p_to_rgb(640, 480, imageptr, myfile.bits);
write(fd, &myfile, sizeof(struct bmp_file));
err:
if(vd.fbfd)
close(vd.fbfd);
if(vd.fd)
close(vd.fd);
exit(0);
return 0;
}
采集图片大小为640*480,采用24位色。在使用的时候,现要在当前目录下touch一个first.bmp文件,不然运行程序的时候会提示open file error!
图片最后为bmp格式,可以直接在xp下用常用图片软件打开,效果还可以。
说明一下,本程序是由其他程序修改而来,为了避免麻烦,对其中一些没有用的地方并没有删除,但是这样不会影响使用。
大家有问题可以联系我。
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u1/57747/showart_1129208.html |
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