基于QT的桌面系统，提供比如ADC采集，浏览器，拍照等功能.zip

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <getopt.h> /* getopt_long() */ #include <fcntl.h> /* low-level i/o */ #include <unistd.h> #include <errno.h> #include <malloc.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <asm/types.h> /* for videodev2.h */ #include <linux/videodev2.h> #include "Camera.h" int Camera::convert_yuv_to_rgb_pixel(int y, int u, int v) { unsigned int pixel32 = 0; unsigned char *pixel = (unsigned char *)&pixel32; int r, g, b; r = y + (1.370705 * (v-128)); g = y - (0.698001 * (v-128)) - (0.337633 * (u-128)); b = y + (1.732446 * (u-128)); if(r > 255) r = 255; if(g > 255) g = 255; if(b > 255) b = 255; if(r < 0) r = 0; if(g < 0) g = 0; if(b < 0) b = 0; pixel[0] = r * 220 / 256; pixel[1] = g * 220 / 256; pixel[2] = b * 220 / 256; return pixel32; } int Camera::convert_yuv_to_rgb_buffer(unsigned char *yuv, unsigned char *rgb, unsigned int width, unsigned int height) { unsigned int in, out = 0; unsigned int pixel_16; unsigned char pixel_24[3]; unsigned int pixel32; int y0, u, y1, v; for(in = 0; in < width * height * 2; in += 4) { pixel_16 = yuv[in + 3] << 24 | yuv[in + 2] << 16 | yuv[in + 1] << 8 | yuv[in + 0]; y0 = (pixel_16 & 0x000000ff); u = (pixel_16 & 0x0000ff00) >> 8; y1 = (pixel_16 & 0x00ff0000) >> 16; v = (pixel_16 & 0xff000000) >> 24; pixel32 = convert_yuv_to_rgb_pixel(y0, u, v); pixel_24[0] = (pixel32 & 0x000000ff); pixel_24[1] = (pixel32 & 0x0000ff00) >> 8; pixel_24[2] = (pixel32 & 0x00ff0000) >> 16; rgb[out++] = pixel_24[0]; rgb[out++] = pixel_24[1]; rgb[out++] = pixel_24[2]; pixel32 = convert_yuv_to_rgb_pixel(y1, u, v); pixel_24[0] = (pixel32 & 0x000000ff); pixel_24[1] = (pixel32 & 0x0000ff00) >> 8; pixel_24[2] = (pixel32 & 0x00ff0000) >> 16; rgb[out++] = pixel_24[0]; rgb[out++] = pixel_24[1]; rgb[out++] = pixel_24[2]; } return 0; } Camera::Camera(char *DEV_NAME, int w, int h)//构造函数 { dev_name=DEV_NAME; io = IO_METHOD_MMAP;//IO_METHOD_READ;//IO_METHOD_MMAP; cap_image_size=0; width=w; height=h; } Camera::~Camera(){ } unsigned int Camera::getImageSize(){ return cap_image_size; } void Camera::CloseDevice() { stop_capturing(); uninit_device(); close_device(); } void Camera::errno_exit(const char * s) { fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); exit(EXIT_FAILURE); } int Camera::xioctl(int fd, int request, void * arg) { int r; do r = ioctl(fd, request, arg); while (-1 == r && EINTR == errno); return r; } int Camera::read_frame(unsigned char *image) { struct v4l2_buffer buf; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; if (-1 == xioctl(fd, VIDIOC_DQBUF, &buf)) //把数据从缓存中读取出来 { switch (errno) { case EAGAIN: return 0; case EIO: default: errno_exit("VIDIOC_DQBUF"); } } assert(buf.index < CAPTURE_BUFFER_NUMBER); memcpy((void*)image,(void*)buffers[0].start,buffers[0].length); if (-1 == xioctl(fd, VIDIOC_QBUF, &buf))//再将其入列，把数据放回缓存队列 errno_exit("VIDIOC_QBUF"); return 1; } void Camera::stop_capturing(void) { enum v4l2_buf_type type; switch (io) { case IO_METHOD_READ: /* Nothing to do. */ break; case IO_METHOD_MMAP: case IO_METHOD_USERPTR: type = V4L2_BUF_TYPE_VIDEO_CAPTURE; /*关闭视频采集命令*/ if (-1 == xioctl(fd, VIDIOC_STREAMOFF, &type)) errno_exit("VIDIOC_STREAMOFF"); break; } } bool Camera::start_capturing(void) { unsigned int i; enum v4l2_buf_type type; for (i = 0; i < CAPTURE_BUFFER_NUMBER; ++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))//再将其入列，把数据放回缓存队列 return false; } type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == xioctl(fd, VIDIOC_STREAMON, &type)) return false; return true; } void Camera::uninit_device(void) { unsigned int i; switch (io) { case IO_METHOD_READ: free(buffers[0].start); break; case IO_METHOD_MMAP: for (i = 0; i < CAPTURE_BUFFER_NUMBER; ++i)//释放申请的内存映射 if (-1 == munmap(buffers[i].start, buffers[i].length)) errno_exit("munmap"); break; case IO_METHOD_USERPTR: for (i = 0; i < CAPTURE_BUFFER_NUMBER; ++i) free(buffers[i].start); break; } } /*********************申请物理内存*******************************/ bool Camera::init_mmap(void) { bool CouldSetFrameRate = false; struct v4l2_streamparm StreamParam; memset(&StreamParam, 0, sizeof StreamParam); StreamParam.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (ioctl(fd, VIDIOC_G_PARM, &StreamParam) < 0) { fprintf(stderr, "could not set frame rate\n"); } else { CouldSetFrameRate = StreamParam.parm.capture.capability & V4L2_CAP_TIMEPERFRAME; } // map the capture buffer... struct v4l2_requestbuffers req; CLEAR (req); req.count = CAPTURE_BUFFER_NUMBER; // 缓冲区内缓冲帧的数目 req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;// 缓冲帧数据格式 req.memory = V4L2_MEMORY_MMAP;//内存映射(memorymapping)方式 if(ioctl(fd, VIDIOC_REQBUFS, &req) < 0) //申请缓冲，count是申请的数量 { fprintf(stderr, "request capture buffer failed\n"); return false; } if (int(req.count) != CAPTURE_BUFFER_NUMBER) { fprintf(stderr, "capture buffer number is wrong\n"); return false; } for (unsigned int i = 0; i < req.count; i++) { struct v4l2_buffer buf; //驱动中的一帧 CLEAR (buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;//buffer类型 buf.memory = V4L2_MEMORY_MMAP;//IO方式，内存映射 buf.index = i;//序号 //映射用户空间，把VIDIOC_REQBUFS中分配的数据缓存转换成物理地址 if (ioctl(fd, VIDIOC_QUERYBUF, &buf) < 0) errno_exit("VIDIOC_QUERYBUF"); buffers[i].length = buf.length; //通过mmap建立映射关系 buffers[i].start = mmap(NULL /* start anywhere */, buf.length, PROT_READ | PROT_WRITE /* required */, MAP_SHARED /* recommended */, fd, buf.m.offset); if (MAP_FAILED == buffers[i].start) return false; } return true; } bool Camera::init_device(void) { v4l2_input input; memset(&input, 0, sizeof(struct v4l2_input)); input.index = 0; if (ioctl(fd, VIDIOC_ENUMINPUT, &input) != 0) { fprintf(stderr, "No matching index found\n"); return false; } if (!input.name) { fprintf(stderr, "No matching index found\n"); return false; } if (ioctl(fd, VIDIOC_S_INPUT, &input) < 0) { fprintf(stderr, "VIDIOC_S_INPUT failed\n"); return false; } struct v4l2_fmtdesc fmt1; //v4l2_fmtdesc : 帧格式结构体 int ret; memset(&fmt1, 0, sizeof(fmt1));//将fmt1结构体填充为0 fmt1.index = 0; //初始化为0，要查询的格式序号 fmt1.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; // 数据流类型，必须永远是V4L2_BUF_TYPE_VIDEO_CAPTURE while ((ret = ioctl(fd, VIDIOC_ENUM_FMT, &fmt1)) == 0) //显示所有支持的格式 { fmt1.index++; printf("{ pixelformat = '%c%c%c%c', description = '%s' }\n",fmt1.pixelformat & 0xFF, (fmt1.pixelformat >> 8) & 0xFF,(fmt1.pixelformat >> 16) & 0xFF, (fmt1.pixelformat >> 24) & 0xFF,fmt1.description); // p