使用了是中星微的Z301B的USB摄像头，在天嵌的板子上运行的，在网络上搜了好久的资料，自己也做了好就，可是还是不行啊，我是没有ARM基础的，接触linux也就一两个星期多，现在真的是没有一点头绪了，记下来吧，计算下来以后慢慢品尝了~~ 一下的程序可以实现图像的采集，可是只能采集一张图片，然后保存为JPG格式的，就算我选择的视频格式为UYVY格式，保存为YUV格式，但是最终文件内部格式还是JPG格式的，因为利用YUV解码器无法查看文件，将后缀改为JPG后可以用图像查看器查看··········现在我知道要在程序中提取出图像的RGB信息，然后进行转换，转换为YUV格式的，但是找了好久，都没有找到相关资料啊··········真的挺郁闷的 ╮(╯▽╰)╭ 下面是提取一张图片的程序源代码，已经实现了，但是程序是别人的，我想改改，将图片保存为YUV格式的，或者视频也可以，但是真不知道如何下手了···经过了两个星期的爬滚，还是一无所获~~~~悲剧啊·························   /*arm-linux-gcc -o usbcamera usbcamera.c ; then download the file and put in the /sbin .*/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CAPTURE_FILE "/media/frame.yuv" #define CLEAR(x) memset (&(x), 0, sizeof (x)) struct buffer { void * start; size_t length; }; static char * dev_name = "/dev/video0"; static int fd = -1; struct buffer * buffers = NULL; static unsigned int n_buffers = 0; FILE *file_fd; static unsigned long file_length; static unsigned char *file_name; 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; int ff = ioctl (fd, VIDIOC_DQBUF, &buf); if(ff<0) printf("failture "); assert (buf.index < n_buffers); printf ("buf.index dq is %d, ",buf.index); fwrite(buffers[buf.index].start, buffers[buf.index].length, 1, file_fd); /////////////////////// FILE *fp = fopen(CAPTURE_FILE, "w+"); if (fp < 0) { printf("open frame data file failed "); return -1; } fwrite(buffers[buf.index].start, 1, buffers[buf.index].length, fp); fclose(fp); printf("Capture one frame saved in %s ", CAPTURE_FILE); //////////////////// ff=ioctl (fd, VIDIOC_QBUF, &buf); if(ff<0) printf("failture VIDIOC_QBUF "); return 1; } int main (int argc,char ** argv) { struct v4l2_capability cap; struct v4l2_format fmt; unsigned int i; enum v4l2_buf_type type; file_fd = fopen("test-mmap.jpg", "w"); fd = open (dev_name, O_RDWR | O_NONBLOCK, 0); int ff=ioctl (fd, VIDIOC_QUERYCAP, &cap); if(ff<0) printf("failture VIDIOC_QUERYCAP "); // Print capability infomations printf("Capability Informations: "); printf(" driver: %s ", cap.driver); printf(" card: %s ", cap.card); printf(" bus_info: %s ", cap.bus_info); printf(" version: %08X ", cap.version); printf(" capabilities: %08X ", cap.capabilities); struct v4l2_fmtdesc fmt1; int ret; memset(&fmt1, 0, sizeof(fmt1)); fmt1.index = 0; fmt1.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; while ((ret = ioctl(fd, VIDIOC_ENUM_FMT, &fmt1)) == 0) { fmt1.index++; printf("{ pixelformat = '%c%c%c%c', description = '%s' } ",fmt1.pixelformat & 0xFF, (fmt1.pixelformat >> 8) & 0xFF,(fmt1.pixelformat >> 16) & 0xFF, (fmt1.pixelformat >> 24) & 0xFF,fmt1.description); } 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_UYVY;//V4L2_PIX_FMT_JPEG; fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; ff = ioctl (fd, VIDIOC_S_FMT, &fmt); if(ff<0) printf("failture VIDIOC_S_FMT "); file_length = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height; struct v4l2_requestbuffers req; CLEAR (req); req.count = 4;//1 req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; ff = ioctl (fd, VIDIOC_REQBUFS, &req); if(ff<0) printf("failture VIDIOC_REQBUFS "); if (req.count < 1) printf("Insufficient buffer memory "); buffers = (struct buffer*)calloc (req.count, sizeof (*buffers)); 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 == ioctl (fd, VIDIOC_QUERYBUF, &buf)) printf ("VIDIOC_QUERYBUF error "); 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) printf ("mmap failed "); } 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 == ioctl (fd, VIDIOC_QBUF, &buf)) printf ("VIDIOC_QBUF failed "); } type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == ioctl (fd, VIDIOC_STREAMON, &type)) printf ("VIDIOC_STREAMON failed "); 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; printf ("select err "); } if (0 == r) { fprintf (stderr, "select timeout "); exit (EXIT_FAILURE); } if (read_frame ()) break; } unmap: for (i = 0; i < n_buffers; ++i) if (-1 == munmap (buffers->start, buffers->length)) printf ("munmap error"); type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == ioctl(fd, VIDIOC_STREAMOFF, &type)) printf("VIDIOC_STREAMOFF"); close (fd); fclose (file_fd); exit (EXIT_SUCCESS); return 0; }