基于Tiny210开发板视频显示

#ifndef VIDEODEVICE_H
#define VIDEODEVICE_H

#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>


#include <sys/ioctl.h>
#include <sys/mman.h>

#include <asm/types.h>
#include <linux/videodev2.h>

#include <QString>
#include <QObject>

#define WIDTH 320
#define HEIGHT 240
#define CLEAR(x) memset(&(x), 0, sizeof(x))

class VideoDevice : public QObject
{
    Q_OBJECT
public:
    VideoDevice(QString dev_name);
    int open_device();
    int close_device();
    int init_device();
    int start_capturing();
    int stop_capturing();
    int uninit_device();
    int get_frame(void **, size_t*);
    int unget_frame();

private:
    int init_mmap();

    struct buffer
    {
        void * start;
        size_t length;
    };
    QString dev_name;
    int fd;
    buffer* buffers;
    unsigned int n_buffers;
    int index;

signals:
    void display_error(QString);

};

#endif // VIDEODEVICE_H

#include "videodevice.h"
#include <stdio.h>

VideoDevice::VideoDevice(QString dev_name)
{
    this->dev_name = dev_name;
    this->fd = -1;
    this->buffers = NULL;
    this->n_buffers = 0;
    this->index = -1;

}

int VideoDevice::open_device()
{
    fd = open(dev_name.toStdString().c_str(), O_RDWR/*|O_NONBLOCK*/, 0);
    // fd = open(dev_name.toStdString().c_str(), O_RDWR|O_NONBLOCK, 0);

    if(-1 == fd)
    {
        emit display_error(tr("open: %1").arg(QString(strerror(errno))));
        return -1;
    }
    return 0;
}

int VideoDevice::close_device()
{
    if(-1 == close(fd))
    {
        emit display_error(tr("close: %1").arg(QString(strerror(errno))));
        return -1;
    }
    return 0;
}

int VideoDevice::init_device()
{
    v4l2_capability cap;
    v4l2_cropcap cropcap;
    v4l2_crop crop;
    v4l2_format fmt;

    if(-1 == ioctl(fd, VIDIOC_QUERYCAP, &cap))
    {
        if(EINVAL == errno)
        {
            emit display_error(tr("%1 is no V4l2 device").arg(dev_name));
        }
        else
        {
            emit display_error(tr("VIDIOC_QUERYCAP: %1").arg(QString(strerror(errno))));
        }
        return -1;
    }

    if(!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE))
    {
        emit display_error(tr("%1 is no video capture device").arg(dev_name));
        return -1;
    }

    if(!(cap.capabilities & V4L2_CAP_STREAMING))
    {
        emit display_error(tr("%1 does not support streaming i/o").arg(dev_name));
        return -1;
    }

    CLEAR(cropcap);

    cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if(0 == ioctl(fd, VIDIOC_CROPCAP, &cropcap))
    {
        CLEAR(crop);
        crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        crop.c = cropcap.defrect;

        if(-1 == ioctl(fd, VIDIOC_S_CROP, &crop))
        {
            if(EINVAL == errno)
            {
                //                emit display_error(tr("VIDIOC_S_CROP not supported"));
            }
            else
            {
                emit display_error(tr("VIDIOC_S_CROP: %1").arg(QString(strerror(errno))));
                return -1;
            }
        }
    }
    else
    {
        emit display_error(tr("VIDIOC_CROPCAP: %1").arg(QString(strerror(errno))));
        return -1;
    }

    CLEAR(fmt);

    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = WIDTH;
    fmt.fmt.pix.height = HEIGHT;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;

    if(-1 == ioctl(fd, VIDIOC_S_FMT, &fmt))
    {
        emit display_error(tr("VIDIOC_S_FMT").arg(QString(strerror(errno))));
        return -1;
    }

    if(-1 == init_mmap())
    {
        return -1;
    }

    fprintf(stderr,"========================\n");

    return 0;
}

int VideoDevice::init_mmap()
{
    v4l2_requestbuffers req;
    CLEAR(req);

    req.count = 4;
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req.memory = V4L2_MEMORY_MMAP;

    if(-1 == ioctl(fd, VIDIOC_REQBUFS, &req))
    {
        if(EINVAL == errno)
        {
            emit display_error(tr("%1 does not support memory mapping").arg(dev_name));
            return -1;
        }
        else
        {
            emit display_error(tr("VIDIOC_REQBUFS %1").arg(QString(strerror(errno))));
            return -1;
        }
    }

    if(req.count < 2)
    {
        emit display_error(tr("Insufficient buffer memory on %1").arg(dev_name));
        return -1;
    }

    buffers = (buffer*)calloc(req.count, sizeof(*buffers));

    if(!buffers)
    {
        emit display_error(tr("out of memory"));
        return -1;
    }

    for(n_buffers = 0; n_buffers < req.count; ++n_buffers)
    {
        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))
        {
            emit display_error(tr("VIDIOC_QUERYBUF: %1").arg(QString(strerror(errno))));
            return -1;
        }

        buffers[n_buffers].length = buf.length;
        buffers[n_buffers].start =
                mmap(NULL, // start anywhere
                     buf.length,
                     PROT_READ | PROT_WRITE,
                     MAP_SHARED,
                     fd, buf.m.offset);

        if(MAP_FAILED == buffers[n_buffers].start)
        {
            emit display_error(tr("mmap %1").arg(QString(strerror(errno))));
            return -1;
        }
    }
    return 0;

}

int VideoDevice::start_capturing()
{
    unsigned int i;
    for(i = 0; i < n_buffers; ++i)
    {
        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, VIDIOC_QBUF, &buf))
        {
            emit display_error(tr("VIDIOC_QBUF: %1").arg(QString(strerror(errno))));
            return -1;
        }
    }

    v4l2_buf_type type;
    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if(-1 == ioctl(fd, VIDIOC_STREAMON, &type))
    {
        emit display_error(tr("VIDIOC_STREAMON: %1").arg(QString(strerror(errno))));
        return -1;
    }
    return 0;
}

int VideoDevice::stop_capturing()
{
    v4l2_buf_type type;
    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    if(-1 == ioctl(fd, VIDIOC_STREAMOFF, &type))
    {
        emit display_error(tr("VIDIOC_STREAMOFF: %1").arg(QString(strerror(errno))));
        return -1;
    }
    return 0;
}

int VideoDevice::uninit_device()
{
    unsigned int i;
    for(i = 0; i < n_buffers; ++i)
    {
        if(-1 == munmap(buffers[i].start, buffers[i].length))
        {
            emit display_error(tr("munmap: %1").arg(QString(strerror(errno))));
            return -1;
        }

    }
    free(buffers);
    return 0;
}

int VideoDevice::get_frame(void **frame_buf, size_t* len)
{
    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, VIDIOC_DQBUF, &queue_buf))
    {
        switch(errno)
        {
        case EAGAIN:
            //            perror("dqbuf");
            return -1;
        case EIO:
            return -1 ;
        default:
            emit display_error(tr("VIDIOC_DQBUF: %1").arg(QString(strerror(errno))));
            return -1;
        }
    }

    *frame_buf = buffers[queue_buf.index].start;
    *len = buffers[queue_buf.index].length;
    index = queue_buf.index;

    return 0;

}

int VideoDevice::unget_frame()
{
    if(index != -1)
    {
        v4l2_buffer queue_buf;
        CLEAR(queue_buf);

        queue_buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        queue_buf.memory = V4L2_MEMORY_MMAP;
        queue_buf.index = index;

        if(-1 == ioctl(fd, VIDIOC_QBUF, &queue_buf))
        {
            emit display_error(tr("VIDIOC_QBUF: %1").arg(QString(strerror(errno))));
            return -1;
        }
        return 0;
    }
    return -1;
}

#ifndef SHOWMAIN_H
#define SHOWMAIN_H

#include <QMainWindow>
#include <QRect>
#include <QTimer>
#include <cv.h>
#include <highgui.h>
#include <QtGui>
#include <QString>
#include <QVector>
#include "videodevice.h"
#include <QImage>
#include <QTime>


namespace Ui {
class ShowMain;
}

class ShowMain : public QMainWindow
{
    Q_OBJECT
    
public:
    explicit ShowMain(QWidget *parent = 0);
    ~ShowMain();
    
private:
    VideoDevice *vd;
    QPainter *painter;
    QLabel *label;
    QImage *frame;
    QImage *frame1;
    IplImage *cvimg;
    QTimer *timer;
    QTimer *timer1;
    uchar *pp;
    uchar * p;
    unsigned int len;
    int rs;

public:
    int convert_yuv_to_rgb_pixel(int y, int u, int v);
    int convert_yuv_to_rgb_buffer(unsigned char *yuv, unsigned char *rgb, unsigned int width, unsigned int height);

private slots:
    void paintEvent1();

private:
    Ui::ShowMain *ui;
};

#endif // SHOWMAIN_H

#include "showmain.h"
#include "ui_showmain.h"
extern "C"
{
#include <stdio.h>
#include <stdlib.h>
}
using namespace std;

ShowMain::ShowMain(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::ShowMain)
{
    ui->setupUi(this);

    pp = (unsigned char *)malloc(WIDTH * HEIGHT/*QWidget::width()*QWidget::height()*/* 4 * sizeof(char));

    frame = new QImage(pp,WIDTH,HEIGHT,QImage::Format_RGB888);   //此处必须使用rgb888格式

    vd = new VideoDevice(tr("/dev/video0"));

    rs = vd->open_device();
    if(-1==rs)
    {
        QMessageBox::warning(this,tr("error"),tr("open /dev/dsp error"),QMessageBox::Yes);
        vd->close_device();
    }

    rs = vd->init_device();
    if(-1==rs)
    {
        QMessageBox::warning(this,tr("error"),tr("init failed"),QMessageBox::Yes);
        vd->close_device();
    }

    rs = vd->start_capturing();
    if(-1==rs)
    {
        QMessageBox::warning(this,tr("error"),tr("start capture failed"),QMessageBox::Yes);
        vd->close_device();
    }

    if(-1==rs)
    {
        QMessageBox::warning(this,tr("error"),tr("get frame failed"),QMessageBox::Yes);
        vd->stop_capturing();
    }

    timer = new QTimer(this);
    connect(timer,SIGNAL(timeout()),this,SLOT(paintEvent1()));
    timer->start(30);
}


void ShowMain::paintEvent1()
{
    rs = vd->get_frame((void **)&p,&len);

    rs = vd->get_frame((void **)&p,&len);

    convert_yuv_to_rgb_buffer(p,(unsigned char*)pp,WIDTH, HEIGHT);

    ui->label->setPixmap(QPixmap::fromImage(*frame,Qt::AutoColor));

    rs = vd->unget_frame();
}
//将yuyv转rgb888
int ShowMain::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;
}

int ShowMain::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;
}

ShowMain::~ShowMain()
{
    delete ui;
}