V4L2_USB摄像头_LCD实时显示代码

#include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <sys/ioctl.h> #include <asm/types.h> /* for videodev2.h */ #include <sys/time.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/mman.h> #include <fcntl.h> #include <error.h> #include <errno.h> #include <malloc.h> #include <linux/fb.h> #include <linux/videodev2.h> #include <assert.h> #include "v4l2_device.h" struct buffer *buffers=NULL; /******************************** *函数功能：初始化摄像头+显示摄像头信息 *********************************/ void init_device(Cam_dev *camdev,Fb_dev *myfb) { unsigned int n_buffers; struct v4l2_requestbuffers req; struct v4l2_capability cap; struct v4l2_fmtdesc fmtdesc; struct v4l2_format fmt; //0、打开摄像头 if((camdev->cfd=open(dev_name,O_RDWR|O_NONBLOCK,0))<0) { printf("device:%s open failed!!\n",dev_name); exit(-1); } //1、查询摄像头信息并打印 if (ioctl(camdev->cfd, VIDIOC_QUERYCAP, &cap) == -1) { printf("Error opening device %s: unable to query device.\n",dev_name); exit(-1); } else { /*打印信息*/ printf("*************Camera-params***************\n"); printf("driver:\t\t%s\n", cap.driver); printf("card:\t\t%s\n", cap.card); printf("bus_info:\t%s\n", cap.bus_info); printf("version:\t%d\n", cap.version); printf("capabilities:\t%x\n", cap.capabilities); printf("*****************end*********************\n"); /*检测摄像头是否支持图像抓取功能*/ if ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) == V4L2_CAP_VIDEO_CAPTURE) { printf("Device %s: supports capture.\n",dev_name); } /*检测摄像头是否支持视频流*/ if ((cap.capabilities & V4L2_CAP_STREAMING) == V4L2_CAP_STREAMING) { printf("Device %s: supports streaming.\n",dev_name); } } //2、打印所有支持格式 /////////////////////////////////////////////////////////////// printf("Support format:\n"); fmtdesc.index = 0; fmtdesc.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; while(ioctl(camdev->cfd,VIDIOC_ENUM_FMT,&fmtdesc)!=-1) { printf("\t%d.%s\n",fmtdesc.index+1,fmtdesc.description); fmtdesc.index++; } ///////////////////////////////////////////////////////////////// //3、设置摄像头格式 fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; fmt.fmt.pix.height = myfb->iHeight; fmt.fmt.pix.width = myfb->iWidth; fmt.fmt.pix.field = V4L2_FIELD_ANY;//V4L2_FIELD_INTERLACED; fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; if (-1 == ioctl(camdev->cfd, VIDIOC_S_FMT, &fmt)) { printf("VIDIOC_S_FMT error!\n"); exit(-1); } if(ioctl(camdev->cfd, VIDIOC_G_FMT, &fmt) == -1) { printf("Unable to get format\n"); exit(-1); } printf("fmt.type:\t\t%d\n",fmt.type); printf("pix.pixelformat:\t%c%c%c%c\n",fmt.fmt.pix.pixelformat & 0xFF, (fmt.fmt.pix.pixelformat >> 8) & 0xFF,(fmt.fmt.pix.pixelformat >> 16) & 0xFF, (fmt.fmt.pix.pixelformat >> 24) & 0xFF); printf("pix.height:\t\t%d\n",fmt.fmt.pix.height); printf("pix.width:\t\t%d\n",fmt.fmt.pix.width); printf("pix.field:\t\t%d\n",fmt.fmt.pix.field); //保存摄像头图像像素信息 camdev->cWidth = fmt.fmt.pix.width; camdev->cHeight = fmt.fmt.pix.height; camdev->cLineBytes = fmt.fmt.pix. bytesperline; camdev->cTotalBytes = fmt.fmt.pix. sizeimage; //4、请求四个缓冲帧 req.count = REBUF_CNT; req.memory = V4L2_MEMORY_MMAP; req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if(ioctl(camdev->cfd,VIDIOC_REQBUFS,&req)==-1) { printf("request for buffers error！\n"); } if (req.count < 2) { printf("Insufficient buffer memory on %s\n",dev_name); exit(-1); } //2、分配图像缓冲结构 （mmap for buffers） buffers = calloc(req.count, sizeof (struct buffer)); if (!buffers) { printf ("Out of memory: error!\n"); exit(-1); } //3、把内核空间中的图像缓冲区映射到用户空间 for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { struct v4l2_buffer buf; CLEAR(buf); buf.index = n_buffers; buf.memory = V4L2_MEMORY_MMAP; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; /*获取要映射屏幕大小*/ if (-1 == ioctl(camdev->cfd, VIDIOC_QUERYBUF, &buf)) { printf ("VIDIOC_QUERYBUF error!\n"); exit(-1); } /*这里的输出是为了检查有关参数的大小*/ camdev->cTotalBytes = buf.length; buffers[n_buffers].length = buf.length; buffers[n_buffers].start = mmap(NULL /* start anywhere */, buf.length, PROT_READ | PROT_WRITE /* required */, MAP_SHARED /* recommended */, camdev->cfd, buf.m.offset); /*不成功则退出*/ if (MAP_FAILED == buffers[n_buffers].start) { printf ("mmap error!\n"); exit(-1); } } /*将缓冲帧放入队列*/ for (n_buffers = 0; n_buffers < req.count; ++n_buffers) { struct v4l2_buffer buf; CLEAR(buf); buf.index = n_buffers; buf.memory = V4L2_MEMORY_MMAP; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == ioctl(camdev->cfd, VIDIOC_QBUF, &buf)) { printf ("VIDIOC_QBUF error!\n"); exit(-1); } } camdev->displaybuf =(char*)malloc(camdev->cTotalBytes); } /******************************** *函数功能：启动捕获图像 *********************************/ void start_capture(int cfd) { /*帧类型，应用程序设置 */ enum v4l2_buf_type type; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; /*启动数据流*/ if (-1 == ioctl(cfd, VIDIOC_STREAMON, &type)) { printf ("VIDIOC_STREAMON error!\n"); exit(-1); } printf ("Start Video Capturing!\n"); } void display_pic(Cam_dev *camdev,Fb_dev *myfb) { struct v4l2_buffer buf; unsigned char* ptmp; unsigned long i,j; CLEAR (buf); buf.memory = V4L2_MEMORY_MMAP; buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; /*取出一缓冲帧*/ if (-1 == ioctl(camdev->cfd, VIDIOC_DQBUF, &buf)) { printf(" VIDIOC_DQBUF error!\n"); exit(-1); } /*检查缓冲帧是否有效*/ assert(buf.index < 4); /*图片格式转换:YUV422->RGB565*/ ptmp = (unsigned char*)buffers[buf.index].start; Pyuv422torgb565(ptmp,camdev->displaybuf,camdev->cHeight,camdev->cWidth); /*图像放大后LCD显示*/ //PicZoomF(camdev,myfb); /*小图像居中显示*/ PicMerge(camdev,myfb); if (-1 == ioctl(camdev->cfd, VIDIOC_QBUF, &buf)) { printf("VIDIOC_QBUF error!\n"); exit(-1); } } /* *函数功能：居中显示小的图像 */ int PicMerge(Cam_dev *camdev,Fb_dev *myfb) { int i; int iX,iY; unsigned char *pucSrc; unsigned char *pucDst; iX = (myfb->iWidth -camdev->cWidth )/2; iY = (myfb->iHeight -camdev->cHeight )/2; //指向放缩后的图像 pucSrc = camdev->displaybuf; //计算空出来的起始的空格 pucDst = myfb->fb_addr + iY * myfb->iLineBytes + iX *myfb->iBpp/8; for (i = 0; i <camdev->cHeight; i++) { memcpy(pucDst, pucSrc, camdev->cLineBytes); pucSrc += camdev->cLineBytes; pucDst += myfb->iLineBytes; } return 0; } int PicZoomF(Cam_dev *camdev,Fb_dev *myfb) { unsigned long dwDstWidth = myfb->iWidth; unsigned long* pdwSrcXTable; unsigned long x; unsigned long y; unsigned long dwSrcY; unsigned char *pucDest; unsigned char *pucSrc; unsigned long dwPixelBytes =myfb->iBpp/2; //创建了放一行像素的空间 pdwSrcXTable = malloc(sizeof(unsigned long) * dwDstWidth); if (NULL == pdwSrcXTable)