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：

1. v4l2视频采集
2. IPU转码
3. framebuffer显示
4. 自定义UDP简单协议进行传输
5. 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
");

    /* 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
");
    }
    printf("Driver Name:%s
Card Name:%s
Bus info:%s
Driver Version:%u.%u.%u
",
            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:
");
    while(ioctl(fd_cam, VIDIOC_ENUM_FMT, &cam_fmtdesc) != -1)
    {
        printf("	%d.%s
",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:
	left:%d
	top:%d
	%d
	height:%d
",
                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
");
        }
    }
    else{
        printf("Can't set cropcap para
");
    }

    /* 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
");
    }
    /* 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
");
    }
    printf("Current data format information:
	%d
	height:%d
",
            cam_format.fmt.pix.width,cam_format.fmt.pix.height);
    ret=initBuffers();
    if(ret<0){
        printf("Buffers init error
");
        //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
");
        return -1;
    }
    if(req.count<2){
        printf("Request frame buffers while insufficient buffer memory
");
        return -1;
    }
    buffers = (struct cam_buffer*)calloc(req.count, sizeof(*buffers));
    if(!buffers){
        printf("Out of memory
");
        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_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_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
", i);
        if(-1 == ioctl(fd_cam, VIDIOC_QBUF, &buf))    {
            printf("VIDIOC_QBUF buffer%d failed
",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
");
        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
",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
");
        return -1;
    }
    printf("queue_buf.index=%d
",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
");
            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
",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;
}

　　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
");
    }
    ipuOutputSize=taskCam.output.paddr= taskCam.output.width * taskCam.output.height
            * fmt_to_bpp(taskCam.output.format)/8;
    printf("ipuOutputSize=%d
",ipuOutputSize);
    ret = ioctl(fd_ipu, IPU_ALLOC, &taskCam.output.paddr);
        if (ret < 0) {
            printf("ioctl IPU_ALLOC fail
");
    }
    outbuf= mmap(0, ipuOutputSize, PROT_READ | PROT_WRITE,
            MAP_SHARED, fd_ipu, taskCam.output.paddr);
    if (!outbuf) {
            printf("mmap ipu output image fail
");
        }
    ipuInputSize  =taskCam.input.paddr=taskCam.input.width * taskCam.input.height
                * fmt_to_bpp(taskCam.input.format)/8;
    printf("ipuInputSize=%d
",ipuInputSize);
    ret = ioctl(fd_ipu, IPU_ALLOC, &taskCam.input.paddr);
    if (ret < 0) {
        printf("ioctl IPU_ALLOC fail: (errno = %d)
", errno);
    }
    inbuf = mmap(0, ipuInputSize, PROT_READ | PROT_WRITE,
                MAP_SHARED, fd_ipu, taskCam.input.paddr);
    if (!inbuf) {
                printf("mmap ipu input image fail
");
            }
}
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
", 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
",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);
}

　　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.
");
        exit(1);
    }
    printf("The framebuffer device was opened successfully.
");

    // Get fixed screen information
    if (ioctl(fd_fb0, FBIOGET_FSCREENINFO, &finfo)) {
        printf("Error reading fixed information.
");
        exit(2);
    }

    // Get variable screen information
    if (ioctl(fd_fb0, FBIOGET_VSCREENINFO, &vinfo)) {
        printf("Error reading variable information.
");
        exit(3);
    }
    printf("%dx%d, %dbpp
", 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
",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.
");
        exit(4);
    }
    printf("The framebuffer device was mapped to memory successfully.
");
}
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);
}

　　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
");
    }
    //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);
}

完整工程

https://github.com/tla001/CapTrans

上位机部分