正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头-Toy模板网

这篇具有很好参考价值的文章主要介绍了正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头。希望对大家有所帮助。如果存在错误或未考虑完全的地方，请大家不吝赐教，您也可以点击"举报违法"按钮提交疑问。

前言

正点原子《I.MX6U 嵌入式 Qt 开发指南》教程使用的是ov系列的摄像头，输出rgb格式，可以直接显示到屏幕，不需要进行格式转化。由于我使用的是yuyv格式的usb摄像头，下面进行适配。

参考：正点原子《I.MX6U 嵌入式 Qt 开发指南》第二十八章视频监控项目

lcd大小：4.3寸 480*272

QT文件： server: video_server client: video_client

一、YUYV摄像头直接使用原始例程

先查看usb摄像头的输出像素格式：v4l2-ctl -d /dev/video1 --all

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

直接修改正点原子的例程，修改pixformat=V4L2_PIX_FMT_YUYV

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

此时使用例程，显示效果如下，很显然原因是摄像头采集的yuyv数据，以Format_RGB16显示到QImage控件上导致了格式异常。

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

二、修改qt例程

1、添加yuyv转rgb的函数到capture_thread.cpp

void yuyv_to_rgb(unsigned char* yuv,unsigned char* rgb)
{
    unsigned int i;
    unsigned char* y0 = yuv + 0;
    unsigned char* u0 = yuv + 1;
    unsigned char* y1 = yuv + 2;
    unsigned char* v0 = yuv + 3;

    unsigned  char* r0 = rgb + 0;
    unsigned  char* g0 = rgb + 1;
    unsigned  char* b0 = rgb + 2;
    unsigned  char* r1 = rgb + 3;
    unsigned  char* g1 = rgb + 4;
    unsigned  char* b1 = rgb + 5;

    float rt0 = 0, gt0 = 0, bt0 = 0, rt1 = 0, gt1 = 0, bt1 = 0;

    for(i = 0; i <= (WIDTH * HEIGHT) / 2 ;i++)
    {
        bt0 = 1.164 * (*y0 - 16) + 2.018 * (*u0 - 128);
        gt0 = 1.164 * (*y0 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
        rt0 = 1.164 * (*y0 - 16) + 1.596 * (*v0 - 128);

        bt1 = 1.164 * (*y1 - 16) + 2.018 * (*u0 - 128);
        gt1 = 1.164 * (*y1 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
        rt1 = 1.164 * (*y1 - 16) + 1.596 * (*v0 - 128);

        if(rt0 > 250)      rt0 = 255;
        if(rt0< 0)        rt0 = 0;

        if(gt0 > 250)     gt0 = 255;
        if(gt0 < 0)    gt0 = 0;

        if(bt0 > 250)    bt0 = 255;
        if(bt0 < 0)    bt0 = 0;

        if(rt1 > 250)    rt1 = 255;
        if(rt1 < 0)    rt1 = 0;

        if(gt1 > 250)    gt1 = 255;
        if(gt1 < 0)    gt1 = 0;

        if(bt1 > 250)    bt1 = 255;
        if(bt1 < 0)    bt1 = 0;

        *r0 = (unsigned char)rt0;
        *g0 = (unsigned char)gt0;
        *b0 = (unsigned char)bt0;

        *r1 = (unsigned char)rt1;
        *g1 = (unsigned char)gt1;
        *b1 = (unsigned char)bt1;

        yuv = yuv + 4;
        rgb = rgb + 6;
        if(yuv == NULL)
          break;

        y0 = yuv;
        u0 = yuv + 1;
        y1 = yuv + 2;
        v0 = yuv + 3;

        r0 = rgb + 0;
        g0 = rgb + 1;
        b0 = rgb + 2;
        r1 = rgb + 3;
        g1 = rgb + 4;
        b1 = rgb + 5;
    }
}

2、声明屏幕缓冲变量

这里的WIDTH和HEIGHT需要根据实际显示设置，由于我的lcd为480*272，因此我设置视频数据为320*240

#define WIDTH     320
#define HEIGHT    240

unsigned char src_buffer[WIDTH*HEIGHT*2];        //用来装v4l2出队的yuyv数据
unsigned char rgb_buffer[WIDTH*HEIGHT*3];        //用来装yuyv转换为rgb的数据

3、yuyv转rgb的实际处理

在帧缓冲出队函数中，对帧缓冲数据进行memcpy到src_buffer，再调用yuyv_to_rgb函数，将转换为rgb的数据保存到rgb_buffer中。然后将rgb_buffer显示到屏幕。

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

三、测试

1、开发板获取摄像头数据测试

将QT工程video_server交叉编译后，放到开发板上运行，查看显示到本地显示的数据是否正常。此时与一开始相比，颜色显示已经正常。

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

2、客户端与服务器通信测试

将QT工程video_client编译后在pc上运行。

将开发板上的video_server勾选开启广播后，运行，即可看到客户端收到的视频数据。

正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头

四、修改后的正点原子video_server项目代码

/******************************************************************
Copyright © Deng Zhimao Co., Ltd. 2021-2030. All rights reserved.
* @projectName   video_server
* @brief         mainwindow.cpp
* @author        Deng Zhimao
* @email         dengzhimao@alientek.com
* @link          www.openedv.com
* @date          2021-11-19
*******************************************************************/
#include "mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    this->setGeometry(0, 0, 480 , 272);     //由于屏幕大小不同，进行了修改

    videoLabel = new QLabel(this);
    videoLabel->setText("未获取到图像数据或未开启本地显示");
    videoLabel->setStyleSheet("QWidget {color: white;}");
    videoLabel->setAlignment(Qt::AlignCenter);
    videoLabel->resize(480, 272);           //由于屏幕大小不同，进行了修改

    checkBox1 = new QCheckBox(this);
    checkBox2 = new QCheckBox(this);

    checkBox1->resize(120, 50);
    checkBox2->resize(120, 50);

    checkBox1->setText("本地显示");
    checkBox2->setText("开启广播");

    checkBox1->setStyleSheet("QCheckBox {color: yellow;}"
                             "QCheckBox:indicator {width: 40; height: 40;}");
    checkBox2->setStyleSheet("QCheckBox {color: yellow;}"
                             "QCheckBox:indicator {width: 40; height: 40}");

    /* 按钮 */
    startCaptureButton = new QPushButton(this);
    startCaptureButton->setCheckable(true);
    startCaptureButton->setText("开始采集摄像头数据");

    /* 设置背景颜色为黑色 */
    QColor color = QColor(Qt::black);
    QPalette p;
    p.setColor(QPalette::Window, color);
    this->setPalette(p);

    /* 样式表 */
    startCaptureButton->setStyleSheet("QPushButton {background-color: white; border-radius: 30}"
                                      "QPushButton:pressed  {background-color: red;}");

    captureThread = new CaptureThread(this);

    connect(startCaptureButton, SIGNAL(clicked(bool)), captureThread, SLOT(setThreadStart(bool)));
    connect(startCaptureButton, SIGNAL(clicked(bool)), this, SLOT(startCaptureButtonClicked(bool)));
    connect(captureThread, SIGNAL(imageReady(QImage)), this, SLOT(showImage(QImage)));
    connect(checkBox1, SIGNAL(clicked(bool)), captureThread, SLOT(setLocalDisplay(bool)));
    connect(checkBox2, SIGNAL(clicked(bool)), captureThread, SLOT(setBroadcast(bool)));
}

MainWindow::~MainWindow()
{
}

void MainWindow::showImage(QImage image)
{
    videoLabel->setPixmap(QPixmap::fromImage(image));
}

void MainWindow::resizeEvent(QResizeEvent *event)
{
    Q_UNUSED(event)
    startCaptureButton->move((this->width() - 200) / 2, this->height() - 80);
    startCaptureButton->resize(200, 60);
    videoLabel->move((this->width() - 480) / 2, (this->height() - 272) / 2);        //由于屏幕大小不同，进行了修改
    checkBox1->move(this->width() - 120, this->height() / 2 - 50);
    checkBox2->move(this->width() - 120, this->height() / 2 + 25);
}

void MainWindow::startCaptureButtonClicked(bool start)
{
    if (start)
        startCaptureButton->setText("停止采集摄像头数据");
    else
        startCaptureButton->setText("开始采集摄像头数据");
}

文章来源地址https://www.toymoban.com/news/detail-420256.html

/******************************************************************
Copyright © Deng Zhimao Co., Ltd. 2021-2030. All rights reserved.
* @projectName   video_server
* @brief         capture_thread.cpp
* @author        Deng Zhimao
* @email         dengzhimao@alientek.com
* @link          www.openedv.com
* @date          2021-11-19
*******************************************************************/
#include "capture_thread.h"
#include <string.h>

#define WIDTH   320     //摄像头拍摄以及显示的大小
#define HEIGHT  240

void yuyv_to_rgb(unsigned char* yuv,unsigned char* rgb)
{
    unsigned int i;
    unsigned char* y0 = yuv + 0;
    unsigned char* u0 = yuv + 1;
    unsigned char* y1 = yuv + 2;
    unsigned char* v0 = yuv + 3;

    unsigned  char* r0 = rgb + 0;
    unsigned  char* g0 = rgb + 1;
    unsigned  char* b0 = rgb + 2;
    unsigned  char* r1 = rgb + 3;
    unsigned  char* g1 = rgb + 4;
    unsigned  char* b1 = rgb + 5;

    float rt0 = 0, gt0 = 0, bt0 = 0, rt1 = 0, gt1 = 0, bt1 = 0;

    for(i = 0; i <= (WIDTH * HEIGHT) / 2 ;i++)
    {
        bt0 = 1.164 * (*y0 - 16) + 2.018 * (*u0 - 128);
        gt0 = 1.164 * (*y0 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
        rt0 = 1.164 * (*y0 - 16) + 1.596 * (*v0 - 128);

        bt1 = 1.164 * (*y1 - 16) + 2.018 * (*u0 - 128);
        gt1 = 1.164 * (*y1 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
        rt1 = 1.164 * (*y1 - 16) + 1.596 * (*v0 - 128);


        if(rt0 > 250)   rt0 = 255;
        if(rt0< 0)      rt0 = 0;

        if(gt0 > 250)   gt0 = 255;
        if(gt0 < 0)     gt0 = 0;

        if(bt0 > 250)   bt0 = 255;
        if(bt0 < 0)     bt0 = 0;

        if(rt1 > 250)   rt1 = 255;
        if(rt1 < 0)     rt1 = 0;

        if(gt1 > 250)   gt1 = 255;
        if(gt1 < 0)     gt1 = 0;

        if(bt1 > 250)   bt1 = 255;
        if(bt1 < 0)     bt1 = 0;

        *r0 = (unsigned char)rt0;
        *g0 = (unsigned char)gt0;
        *b0 = (unsigned char)bt0;

        *r1 = (unsigned char)rt1;
        *g1 = (unsigned char)gt1;
        *b1 = (unsigned char)bt1;

        yuv = yuv + 4;
        rgb = rgb + 6;
        if(yuv == NULL)
          break;

        y0 = yuv;
        u0 = yuv + 1;
        y1 = yuv + 2;
        v0 = yuv + 3;

        r0 = rgb + 0;
        g0 = rgb + 1;
        b0 = rgb + 2;
        r1 = rgb + 3;
        g1 = rgb + 4;
        b1 = rgb + 5;
    }
}

void CaptureThread::run()
{
    /* 下面的代码请参考正点原子C应用编程V4L2章节，摄像头编程，这里不作解释 */
#ifdef linux
#ifndef __arm__
    return;
#endif
    int video_fd = -1;
    struct v4l2_format fmt;
    struct v4l2_requestbuffers req_bufs;
    static struct v4l2_buffer buf;
    int n_buf;
    struct buffer_info bufs_info[VIDEO_BUFFER_COUNT];
    enum v4l2_buf_type type;

    unsigned char src_buffer[WIDTH*HEIGHT*2];
    unsigned char rgb_buffer[WIDTH*HEIGHT*2];

    video_fd = open(VIDEO_DEV, O_RDWR);
    if (0 > video_fd) {
        printf("ERROR: failed to open video device %s\n", VIDEO_DEV);
        return ;
    }

    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 (0 > ioctl(video_fd, VIDIOC_S_FMT, &fmt)) {
        printf("ERROR: failed to VIDIOC_S_FMT\n");
        close(video_fd);
        return ;
    }

    if (0 > ioctl(video_fd, VIDIOC_G_FMT, &fmt)) {
        printf("ERROR: failed to VIDIOC_S_FMT\n");
        close(video_fd);
        return ;
    }
    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.width:\t\t%d\n",fmt.fmt.pix.width);
    printf("pix.height:\t\t%d\n",fmt.fmt.pix.height);
    printf("pix.field:\t\t%d\n",fmt.fmt.pix.field);

    req_bufs.count = VIDEO_BUFFER_COUNT;
    req_bufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req_bufs.memory = V4L2_MEMORY_MMAP;

    if (0 > ioctl(video_fd, VIDIOC_REQBUFS, &req_bufs)) {
        printf("ERROR: failed to VIDIOC_REQBUFS\n");
        return ;
    }

    buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {

        buf.index = n_buf;
        if (0 > ioctl(video_fd, VIDIOC_QUERYBUF, &buf)) {
            printf("ERROR: failed to VIDIOC_QUERYBUF\n");
            return ;
        }

        bufs_info[n_buf].length = buf.length;
        bufs_info[n_buf].start = mmap(NULL, buf.length,
                                      PROT_READ | PROT_WRITE, MAP_SHARED,
                                      video_fd, buf.m.offset);
        if (MAP_FAILED == bufs_info[n_buf].start) {
            printf("ERROR: failed to mmap video buffer, size 0x%x\n", buf.length);
            return ;
        }
    }

    for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {

        buf.index = n_buf;
        if (0 > ioctl(video_fd, VIDIOC_QBUF, &buf)) {
            printf("ERROR: failed to VIDIOC_QBUF\n");
            return ;
        }
    }

    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    if (0 > ioctl(video_fd, VIDIOC_STREAMON, &type)) {
        printf("ERROR: failed to VIDIOC_STREAMON\n");
        return ;
    }

    while (startFlag) {

        for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {

            buf.index = n_buf;

            //出队
            if (0 > ioctl(video_fd, VIDIOC_DQBUF, &buf)) {
                printf("ERROR: failed to VIDIOC_DQBUF\n");
                return;
            }
//            printf("now memcpy the src buf, buf start=%d, len=%d\r\n", bufs_info[n_buf].start, bufs_info[n_buf].length);
            memcpy(src_buffer, bufs_info[n_buf].start, bufs_info[n_buf].length);                        //将帧缓冲数据复制到到src_buffer
            yuyv_to_rgb((unsigned char*)bufs_info[n_buf].start, rgb_buffer);                            //yuyv转rgb
            QImage qImage(rgb_buffer, fmt.fmt.pix.width, fmt.fmt.pix.height, QImage::Format_RGB16);     //显示到屏幕
//            QImage qImage((unsigned char*)bufs_info[n_buf].start, fmt.fmt.pix.width, fmt.fmt.pix.height, QImage::Format_RGB16);

            /* 是否开启本地显示，开启本地显示可能会导致开启广播卡顿，它们互相制约 */
            if (startLocalDisplay)
                emit imageReady(qImage);

            /* 是否开启广播，开启广播会导致本地显示卡顿，它们互相制约 */
            if (startBroadcast) {
                /* udp套接字 */
                QUdpSocket udpSocket;

                /* QByteArray类型 */
                QByteArray byte;

                /* 建立一个用于IO读写的缓冲区 */
                QBuffer buff(&byte);

                /* image转为byte的类型，再存入buff */
                qImage.save(&buff, "JPEG", -1);

                /* 转换为base64Byte类型 */
                QByteArray base64Byte = byte.toBase64();

                /* 由udpSocket以广播的形式传输数据，端口号为8888 */
                udpSocket.writeDatagram(base64Byte.data(), base64Byte.size(), QHostAddress::Broadcast, 8888);
            }

            //入队
            if (0 > ioctl(video_fd, VIDIOC_QBUF, &buf)) {
                printf("ERROR: failed to VIDIOC_QBUF\n");
                return;
            }
        }
    }

    msleep(800);//at lease 650

    for (int i = 0; i < VIDEO_BUFFER_COUNT; i++) {
        munmap(bufs_info[i].start, buf.length);
    }

    close(video_fd);
#endif
}

到了这里，关于正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！