实战小项目之嵌入式linux图像采集与传输
项目简介
本次编程实战主要是围绕嵌入式linux v4l2采集框架展开，包括以下几个部分：
- v4l2视频采集
- IPU转码
- framebuffer显示
- 自定义UDP简单协议进行传输
- 上位机软件（QT）
首先是采集部分
#include "includes.h" int fd_cam; struct cam_buffer *buffers=NULL; unsigned int n_buffers=0; int frameIndex=0; void initVideo() { int ret; struct v4l2_capability cam_cap; //显示设备信息 struct v4l2_cropcap cam_cropcap; //设置摄像头的捕捉能力 struct v4l2_fmtdesc cam_fmtdesc; //查询所有支持的格式：VIDIOC_ENUM_FMT struct v4l2_crop cam_crop; //图像的缩放 struct v4l2_format cam_format; //设置摄像头的视频制式、帧格式等 /*设备的打开*/ fd_cam = open( USB_VIDEO, O_RDWR ); if( fd_cam<0 ) printf("Can\'t open video device\n"); /* 使用IOCTL命令VIDIOC_QUERYCAP，获取摄像头的基本信息*/ ret = ioctl( fd_cam,VIDIOC_QUERYCAP,&cam_cap ); if( ret<0 ) { printf("Can\'t get device information: VIDIOCGCAP\n"); } printf("Driver Name:%s\nCard Name:%s\nBus info:%s\nDriver Version:%u.%u.%u\n", cam_cap.driver,cam_cap.card,cam_cap.bus_info,(cam_cap.version>>16)&0XFF, (cam_cap.version>>8)&0XFF,cam_cap.version&0XFF); /* 使用IOCTL命令VIDIOC_ENUM_FMT，获取摄像头所有支持的格式*/ cam_fmtdesc.index=0; cam_fmtdesc.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; printf("Support format:\n"); while(ioctl(fd_cam, VIDIOC_ENUM_FMT, &cam_fmtdesc) != -1) { printf("\t%d.%s\n",cam_fmtdesc.index+1,cam_fmtdesc.description); cam_fmtdesc.index++; } /* 使用IOCTL命令VIDIOC_CROPCAP，获取摄像头的捕捉能力*/ cam_cropcap.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; if(0 == ioctl(fd_cam, VIDIOC_CROPCAP, &cam_cropcap)){ printf("Default rec:\n\tleft:%d\n\ttop:%d\n\twidth:%d\n\theight:%d\n", cam_cropcap.defrect.left,cam_cropcap.defrect.top, cam_cropcap.defrect.width,cam_cropcap.defrect.height); /* 使用IOCTL命令VIDIOC_S_CROP，获取摄像头的窗口取景参数*/ cam_crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; cam_crop.c = cam_cropcap.defrect;//默认取景窗口大小 if(-1 == ioctl(fd_cam, VIDIOC_S_CROP, &cam_crop)){ //printf("Can\'t set crop para\n"); } } else{ printf("Can\'t set cropcap para\n"); } /* 使用IOCTL命令VIDIOC_S_FMT，设置摄像头帧信息*/ cam_format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; cam_format.fmt.pix.width = 640; cam_format.fmt.pix.height = 480; cam_format.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;//要和摄像头支持的类型对应 cam_format.fmt.pix.field = V4L2_FIELD_INTERLACED; ret=ioctl(fd_cam, VIDIOC_S_FMT, &cam_format); if(ret<0){ printf("Can\'t set frame information\n"); } /* 使用IOCTL命令VIDIOC_G_FMT，获取摄像头帧信息*/ cam_format.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; ret=ioctl(fd_cam, VIDIOC_G_FMT, &cam_format); if(ret<0){ printf("Can\'t get frame information\n"); } printf("Current data format information:\n\twidth:%d\n\theight:%d\n", cam_format.fmt.pix.width,cam_format.fmt.pix.height); ret=initBuffers(); if(ret<0){ printf("Buffers init error\n"); //exit(-1); } } void closeVideo() { //stopCapture(); //freeBuffers(); close(fd_cam); } int initBuffers() { int ret; /* 使用IOCTL命令VIDIOC_REQBUFS，申请帧缓冲*/ struct v4l2_requestbuffers req; CLEAR(req); req.count=4; req.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; ret=ioctl(fd_cam, VIDIOC_REQBUFS, &req); if(ret<0){ printf("Request frame buffers failed\n"); return -1; } if(req.count<2){ printf("Request frame buffers while insufficient buffer memory\n"); return -1; } buffers = (struct cam_buffer*)calloc(req.count, sizeof(*buffers)); if(!buffers){ printf("Out of memory\n"); return -1; } for(n_buffers = 0; n_buffers < req.count; n_buffers++){ struct v4l2_buffer buf; CLEAR(buf); // 查询序号为n_buffers 的缓冲区，得到其起始物理地址和大小 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; buf.index = n_buffers; ret=ioctl(fd_cam, VIDIOC_QUERYBUF, &buf); if(ret<0 ) { printf("VIDIOC_QUERYBUF %d failed\n",n_buffers); return -1; } buffers[n_buffers].length = buf.length; // 映射内存 buffers[n_buffers].start = mmap(NULL, // start anywhere buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, fd_cam, buf.m.offset); if(MAP_FAILED == buffers[n_buffers].start) { printf("mmap buffer%d failed\n",n_buffers); return -1; } } return 0; } int startCapture() { unsigned int i; //struct v4l2_buffer buf; 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; // fprintf(stderr, "n_buffers: %d\n", i); if(-1 == ioctl(fd_cam, VIDIOC_QBUF, &buf)) { printf("VIDIOC_QBUF buffer%d failed\n",i); return -1; } } enum v4l2_buf_type type; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if(-1 == ioctl(fd_cam, VIDIOC_STREAMON, &type)){ printf("VIDIOC_STREAMON error"); return -1; } return 0; } int stopCapture() { enum v4l2_buf_type type; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if(-1 == ioctl(fd_cam, VIDIOC_STREAMOFF, &type)){ printf("VIDIOC_STREAMOFF error\n"); return -1; } return 0; } int freeBuffers() { unsigned int i; for(i = 0; i < n_buffers; ++i){ if(-1 == munmap(buffers[i].start, buffers[i].length)){ printf("munmap buffer%d failed\n",i); return -1; } } free(buffers); return 0; } int getFrame(void **frame_buf, size_t* len) { struct v4l2_buffer queue_buf; CLEAR(queue_buf); queue_buf.type=V4L2_BUF_TYPE_VIDEO_CAPTURE; queue_buf.memory = V4L2_MEMORY_MMAP; if(-1 == ioctl(fd_cam, VIDIOC_DQBUF, &queue_buf)){ printf("VIDIOC_DQBUF error\n"); return -1; } printf("queue_buf.index=%d\n",queue_buf.index); //pthread_rwlock_wrlock(&rwlock); *frame_buf = buffers[queue_buf.index].start; *len = buffers[queue_buf.index].length; frameIndex = queue_buf.index; //pthread_rwlock_unlock(&rwlock); return 0; } int backFrame() { if(frameIndex != -1){ struct v4l2_buffer queue_buf; CLEAR(queue_buf); queue_buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; queue_buf.memory = V4L2_MEMORY_MMAP; queue_buf.index = frameIndex; if(-1 == ioctl(fd_cam, VIDIOC_QBUF, &queue_buf)){ printf("VIDIOC_QBUF error\n"); return -1; } return 0; } return -1; } /*yuv格式转换为rgb格式*/ int 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; struct timeval starttime,endtime; gettimeofday(&starttime,0); 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; //pthread_rwlock_wrlock(&rwlock); rgb[out++] = pixel_24[0]; rgb[out++] = pixel_24[1]; rgb[out++] = pixel_24[2]; //pthread_rwlock_unlock(&rwlock); 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; //pthread_rwlock_wrlock(&rwlock); rgb[out++] = pixel_24[0]; rgb[out++] = pixel_24[1]; rgb[out++] = pixel_24[2]; //pthread_rwlock_unlock(&rwlock); } gettimeofday(&endtime,0); double timeuse = 1000000*(endtime.tv_sec - starttime.tv_sec)+endtime.tv_usec-starttime.tv_usec; timeuse /=1000;//除以1000则进行毫秒计时，如果除以1000000则进行秒级别计时，如果除以1则进行微妙级别计时 printf("yuv2rgb use %f ms\n",timeuse); return 0; } int 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; }
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之后是IPU部分
#include "includes.h" int fd_ipu=0; struct ipu_task taskCam; struct timeval begintime, endtime; unsigned int ipuOutputSize=0,ipuInputSize=0; void *inbuf=NULL; void *outbuf=NULL; /***************与软件解码对应的IPU解码**************************/ void initIPU() { int ret; CLEAR(taskCam); // Input image size and format taskCam.input.width = 640; taskCam.input.height = 480; taskCam.input.format = v4l2_fourcc(\'Y\', \'U\', \'Y\', \'V\'); // // taskCam.input.crop.pos.x = 0; // taskCam.input.crop.pos.y = 0; // taskCam.input.crop.w = 0; // taskCam.input.crop.h = 0; // Output image size and format taskCam.output.width = 640; taskCam.output.height = 480; taskCam.output.format = v4l2_fourcc(\'B\', \'G\', \'R\', \'3\'); // taskCam.output.crop.pos.x = 300; // taskCam.output.crop.pos.y = 300; // taskCam.output.crop.w = 300; // taskCam.output.crop.h = 300; // Open IPU device fd_ipu = open(IPUDEV, O_RDWR, 0); if (fd_ipu < 0) { printf("open ipu dev fail\n"); } ipuOutputSize=taskCam.output.paddr= taskCam.output.width * taskCam.output.height * fmt_to_bpp(taskCam.output.format)/8; printf("ipuOutputSize=%d\n",ipuOutputSize); ret = ioctl(fd_ipu, IPU_ALLOC, &taskCam.output.paddr); if (ret < 0) { printf("ioctl IPU_ALLOC fail\n"); } outbuf= mmap(0, ipuOutputSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd_ipu, taskCam.output.paddr); if (!outbuf) { printf("mmap ipu output image fail\n"); } ipuInputSize =taskCam.input.paddr=taskCam.input.width * taskCam.input.height * fmt_to_bpp(taskCam.input.format)/8; printf("ipuInputSize=%d\n",ipuInputSize); ret = ioctl(fd_ipu, IPU_ALLOC, &taskCam.input.paddr); if (ret < 0) { printf("ioctl IPU_ALLOC fail: (errno = %d)\n", errno); } inbuf = mmap(0, ipuInputSize, PROT_READ | PROT_WRITE, MAP_SHARED, fd_ipu, taskCam.input.paddr); if (!inbuf) { printf("mmap ipu input image fail\n"); } } void IPUConvent(void *in,void *out) { int ret; memcpy(inbuf, in, ipuInputSize); gettimeofday(&begintime, NULL); // Perform color space conversion ret = ioctl(fd_ipu, IPU_QUEUE_TASK, &taskCam); if (ret < 0) { printf("ioct IPU_QUEUE_TASK fail %x\n", ret); } gettimeofday(&endtime, NULL); double timeuse = 1000000*(endtime.tv_sec - begintime.tv_sec)+endtime.tv_usec-begintime.tv_usec; timeuse /=1000;//除以1000则进行毫秒计时，如果除以1000000则进行秒级别计时，如果除以1则进行微妙级别计时 printf("yuv2rgb use %f ms\n",timeuse); memcpy(out,outbuf,ipuOutputSize); } void closeIPU() { if(rgbFrame)munmap(rgbFrame, ipuOutputSize); if(inbuf)munmap(inbuf, ipuInputSize); if (taskCam.input.paddr) ioctl(fd_ipu, IPU_FREE, &taskCam.input.paddr); }
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然后是framebuffer显示
#include "includes.h" int fd_fb0; long int screensize = 0; char *fb_buf = 0; struct fb_var_screeninfo vinfo; struct fb_fix_screeninfo finfo; void InitDisOnFrameBuffer() { // Open the file for reading and writing fd_fb0 = open(DISON_FB0, O_RDWR); if (!fd_fb0) { printf("Error: cannot open framebuffer device.\n"); exit(1); } printf("The framebuffer device was opened successfully.\n"); // Get fixed screen information if (ioctl(fd_fb0, FBIOGET_FSCREENINFO, &finfo)) { printf("Error reading fixed information.\n"); exit(2); } // Get variable screen information if (ioctl(fd_fb0, FBIOGET_VSCREENINFO, &vinfo)) { printf("Error reading variable information.\n"); exit(3); } printf("%dx%d, %dbpp\n", vinfo.xres, vinfo.yres, vinfo.bits_per_pixel ); // Figure out the size of the screen in bytes screensize = vinfo.xres * vinfo.yres * vinfo.bits_per_pixel / 8; printf("screensize=%d\n",screensize); // Map the device to memory fb_buf = (char *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED, fd_fb0, 0); if ((int)fb_buf == -1) { printf("Error: failed to map framebuffer device to memory.\n"); exit(4); } printf("The framebuffer device was mapped to memory successfully.\n"); } void DisOnFrameBuffer(unsigned char *frame) { //memcpy(fb_buf,frame,640* 480* 3 * sizeof(char)); int x = 0, y = 0; long int location = 0; // Figure out where in memory to put the pixel for ( y = 0; y < 480; y++ ) for ( x = 0; x < 640; x++ ) { location = (x+vinfo.xoffset) * (vinfo.bits_per_pixel/8) + (y+vinfo.yoffset) * finfo.line_length; if ( vinfo.bits_per_pixel == 32 ) { //rgb32 bgra *(fb_buf + location ) = *frame;frame++; // Some blue *(fb_buf + location + 1) = *frame;frame++; // A little green *(fb_buf + location + 2) = *frame;frame++; //A lot of red//frame[480*y+x+2]; *(fb_buf + location + 3) = 0; // No transparency } else { //assume 16bpp int b = 10; int g = (x-100)/6; // A little green int r = 31-(y-100)/16; // A lot of red unsigned short int t = r<<11 | g << 5 | b; *((unsigned short int*)(fb_buf + location)) = t; } } } void CloseDisOnFrameBuffer() { munmap(fb_buf, screensize); close(fd_fb0); }
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UDP部分
#include "includes.h" struct sockaddr_in serveraddr; int confd; char udpRecbuf[MAXLINE]; void initUDPTrans() { //1.创建一个socket confd=socket(AF_INET,SOCK_DGRAM,0); //2.初始化服务器地址 bzero(&serveraddr,sizeof(serveraddr)); serveraddr.sin_family=AF_INET; // inet_pton(AF_INET,SEVER_IP,&serveraddr.sin_addr.s_addr); serveraddr.sin_port =htons(SERVER_PORT); } void sendUDPdata(void *datas,unsigned int size) { size_t len,i,j;//分成1800块 每块512 char tempflag; struct udptransbuf data; for(i=0;i<24;i++){ memcpy(data.buf,datas+i*BLOCKSIZE,BLOCKSIZE); // for(j=0;j<BLOCKSIZE;j++) // data.buf[j]= (unsigned char*)(datas+i*BLOCKSIZE+j); if(i==0){ tempflag=\'a\'; data.flag=tempflag; } else{ tempflag++; data.flag=tempflag; } //3向务器发送数据 len=sendto(confd,(void*)&data,sizeof(data),0,(struct sockaddr *)&serveraddr,sizeof(serveraddr)); if(len<0) printf("UDP send failed\n"); } //char udpSendbuf[MAXLINE]="125wwew3332354#@$#"; } void recUDPdata(char *udpRecbuf)//这里要求传入的是数组，要是指针需要修改 { size_t len; len=recvfrom(confd,udpRecbuf,sizeof(udpRecbuf),0,NULL,0); write(STDIN_FILENO,udpRecbuf,len); } void closeUDPtrans() { close(confd); }
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完整工程
https://github.com/tla001/CapTrans
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