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正点原子imx6ull: QT视频监控项目使用yuyv格式的usb摄像头_qt显示yuv摄像

作者：从前慢现在也慢 | 2024-06-13 07:11:45

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qt显示yuv摄像

目录

前言

二、修改qt例程

1、添加yuyv转rgb的函数到capture_thread.cpp

2、声明屏幕缓冲变量

3、yuyv转rgb的实际处理

 三、测试

    1、开发板获取摄像头数据测试

    2、客户端与服务器通信测试

四、修改后的正点原子video_server项目代码

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

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

 

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。

二、修改qt例程

1、添加yuyv转rgb的函数到capture_thread.cpp

  1. void yuyv_to_rgb(unsigned char* yuv,unsigned char* rgb)
  2. {
  3.     unsigned int i;
  4.     unsigned char* y0 = yuv + 0;
  5.     unsigned char* u0 = yuv + 1;
  6.     unsigned char* y1 = yuv + 2;
  7.     unsigned char* v0 = yuv + 3;
  8.  
  9.     unsigned  char* r0 = rgb + 0;
  10.     unsigned  char* g0 = rgb + 1;
  11.     unsigned  char* b0 = rgb + 2;
  12.     unsigned  char* r1 = rgb + 3;
  13.     unsigned  char* g1 = rgb + 4;
  14.     unsigned  char* b1 = rgb + 5;
  15.  
  16.     float rt0 = 0, gt0 = 0, bt0 = 0, rt1 = 0, gt1 = 0, bt1 = 0;
  17.  
  18.     for(i = 0; i <= (WIDTH * HEIGHT) / 2 ;i++)
  19.     {
  20.         bt0 = 1.164 * (*y0 - 16) + 2.018 * (*u0 - 128);
  21.         gt0 = 1.164 * (*y0 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
  22.         rt0 = 1.164 * (*y0 - 16) + 1.596 * (*v0 - 128);
  23.  
  24.         bt1 = 1.164 * (*y1 - 16) + 2.018 * (*u0 - 128);
  25.         gt1 = 1.164 * (*y1 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
  26.         rt1 = 1.164 * (*y1 - 16) + 1.596 * (*v0 - 128);
  27.  
  28.         if(rt0 > 250)      rt0 = 255;
  29.         if(rt0< 0)        rt0 = 0;
  30.  
  31.         if(gt0 > 250)     gt0 = 255;
  32.         if(gt0 < 0)    gt0 = 0;
  33.  
  34.         if(bt0 > 250)    bt0 = 255;
  35.         if(bt0 < 0)    bt0 = 0;
  36.  
  37.         if(rt1 > 250)    rt1 = 255;
  38.         if(rt1 < 0)    rt1 = 0;
  39.  
  40.         if(gt1 > 250)    gt1 = 255;
  41.         if(gt1 < 0)    gt1 = 0;
  42.  
  43.         if(bt1 > 250)    bt1 = 255;
  44.         if(bt1 < 0)    bt1 = 0;
  45.  
  46.         *r0 = (unsigned char)rt0;
  47.         *g0 = (unsigned char)gt0;
  48.         *b0 = (unsigned char)bt0;
  49.  
  50.         *r1 = (unsigned char)rt1;
  51.         *g1 = (unsigned char)gt1;
  52.         *b1 = (unsigned char)bt1;
  53.  
  54.         yuv = yuv + 4;
  55.         rgb = rgb + 6;
  56.         if(yuv == NULL)
  57.           break;
  58.  
  59.         y0 = yuv;
  60.         u0 = yuv + 1;
  61.         y1 = yuv + 2;
  62.         v0 = yuv + 3;
  63.  
  64.         r0 = rgb + 0;
  65.         g0 = rgb + 1;
  66.         b0 = rgb + 2;
  67.         r1 = rgb + 3;
  68.         g1 = rgb + 4;
  69.         b1 = rgb + 5;
  70.     }
  71. }

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

  1. #define WIDTH     320
  2. #define HEIGHT    240
  3.  
  4. unsigned char src_buffer[WIDTH*HEIGHT*2];        //用来装v4l2出队的yuyv数据
  5. 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。

 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。

    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。

四、修改后的正点原子video_server项目代码

  1. /******************************************************************
  2. Copyright © Deng Zhimao Co., Ltd. 2021-2030. All rights reserved.
  3. * @projectName   video_server
  4. * @brief         mainwindow.cpp
  5. * @author        Deng Zhimao
  6. * @email         dengzhimao@alientek.com
  7. * @link          www.openedv.com
  8. * @date          2021-11-19
  9. *******************************************************************/
  10. #include "mainwindow.h"
  11.  
  12. MainWindow::MainWindow(QWidget *parent)
  13.     : QMainWindow(parent)
  14. {
  15.     this->setGeometry(0, 0, 480 , 272);     //由于屏幕大小不同，进行了修改
  16.  
  17.     videoLabel = new QLabel(this);
  18.     videoLabel->setText("未获取到图像数据或未开启本地显示");
  19.     videoLabel->setStyleSheet("QWidget {color: white;}");
  20.     videoLabel->setAlignment(Qt::AlignCenter);
  21.     videoLabel->resize(480, 272);           //由于屏幕大小不同，进行了修改
  22.  
  23.     checkBox1 = new QCheckBox(this);
  24.     checkBox2 = new QCheckBox(this);
  25.  
  26.     checkBox1->resize(120, 50);
  27.     checkBox2->resize(120, 50);
  28.  
  29.     checkBox1->setText("本地显示");
  30.     checkBox2->setText("开启广播");
  31.  
  32.     checkBox1->setStyleSheet("QCheckBox {color: yellow;}"
  33.                              "QCheckBox:indicator {width: 40; height: 40;}");
  34.     checkBox2->setStyleSheet("QCheckBox {color: yellow;}"
  35.                              "QCheckBox:indicator {width: 40; height: 40}");
  36.  
  37.     /* 按钮 */
  38.     startCaptureButton = new QPushButton(this);
  39.     startCaptureButton->setCheckable(true);
  40.     startCaptureButton->setText("开始采集摄像头数据");
  41.  
  42.     /* 设置背景颜色为黑色 */
  43.     QColor color = QColor(Qt::black);
  44.     QPalette p;
  45.     p.setColor(QPalette::Window, color);
  46.     this->setPalette(p);
  47.  
  48.     /* 样式表 */
  49.     startCaptureButton->setStyleSheet("QPushButton {background-color: white; border-radius: 30}"
  50.                                       "QPushButton:pressed  {background-color: red;}");
  51.  
  52.     captureThread = new CaptureThread(this);
  53.  
  54.     connect(startCaptureButton, SIGNAL(clicked(bool)), captureThread, SLOT(setThreadStart(bool)));
  55.     connect(startCaptureButton, SIGNAL(clicked(bool)), this, SLOT(startCaptureButtonClicked(bool)));
  56.     connect(captureThread, SIGNAL(imageReady(QImage)), this, SLOT(showImage(QImage)));
  57.     connect(checkBox1, SIGNAL(clicked(bool)), captureThread, SLOT(setLocalDisplay(bool)));
  58.     connect(checkBox2, SIGNAL(clicked(bool)), captureThread, SLOT(setBroadcast(bool)));
  59. }
  60.  
  61. MainWindow::~MainWindow()
  62. {
  63. }
  64.  
  65. void MainWindow::showImage(QImage image)
  66. {
  67.     videoLabel->setPixmap(QPixmap::fromImage(image));
  68. }
  69.  
  70. void MainWindow::resizeEvent(QResizeEvent *event)
  71. {
  72.     Q_UNUSED(event)
  73.     startCaptureButton->move((this->width() - 200) / 2, this->height() - 80);
  74.     startCaptureButton->resize(200, 60);
  75.     videoLabel->move((this->width() - 480) / 2, (this->height() - 272) / 2);        //由于屏幕大小不同，进行了修改
  76.     checkBox1->move(this->width() - 120, this->height() / 2 - 50);
  77.     checkBox2->move(this->width() - 120, this->height() / 2 + 25);
  78. }
  79.  
  80. void MainWindow::startCaptureButtonClicked(bool start)
  81. {
  82.     if (start)
  83.         startCaptureButton->setText("停止采集摄像头数据");
  84.     else
  85.         startCaptureButton->setText("开始采集摄像头数据");
  86. }
  87.

 

  1. /******************************************************************
  2. Copyright © Deng Zhimao Co., Ltd. 2021-2030. All rights reserved.
  3. * @projectName   video_server
  4. * @brief         capture_thread.cpp
  5. * @author        Deng Zhimao
  6. * @email         dengzhimao@alientek.com
  7. * @link          www.openedv.com
  8. * @date          2021-11-19
  9. *******************************************************************/
  10. #include "capture_thread.h"
  11. #include <string.h>
  12.  
  13. #define WIDTH   320     //摄像头拍摄以及显示的大小
  14. #define HEIGHT  240
  15.  
  16. void yuyv_to_rgb(unsigned char* yuv,unsigned char* rgb)
  17. {
  18.     unsigned int i;
  19.     unsigned char* y0 = yuv + 0;
  20.     unsigned char* u0 = yuv + 1;
  21.     unsigned char* y1 = yuv + 2;
  22.     unsigned char* v0 = yuv + 3;
  23.  
  24.     unsigned  char* r0 = rgb + 0;
  25.     unsigned  char* g0 = rgb + 1;
  26.     unsigned  char* b0 = rgb + 2;
  27.     unsigned  char* r1 = rgb + 3;
  28.     unsigned  char* g1 = rgb + 4;
  29.     unsigned  char* b1 = rgb + 5;
  30.  
  31.     float rt0 = 0, gt0 = 0, bt0 = 0, rt1 = 0, gt1 = 0, bt1 = 0;
  32.  
  33.     for(i = 0; i <= (WIDTH * HEIGHT) / 2 ;i++)
  34.     {
  35.         bt0 = 1.164 * (*y0 - 16) + 2.018 * (*u0 - 128);
  36.         gt0 = 1.164 * (*y0 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
  37.         rt0 = 1.164 * (*y0 - 16) + 1.596 * (*v0 - 128);
  38.  
  39.         bt1 = 1.164 * (*y1 - 16) + 2.018 * (*u0 - 128);
  40.         gt1 = 1.164 * (*y1 - 16) - 0.813 * (*v0 - 128) - 0.394 * (*u0 - 128);
  41.         rt1 = 1.164 * (*y1 - 16) + 1.596 * (*v0 - 128);
  42.  
  43.  
  44.         if(rt0 > 250)   rt0 = 255;
  45.         if(rt0< 0)      rt0 = 0;
  46.  
  47.         if(gt0 > 250)   gt0 = 255;
  48.         if(gt0 < 0)     gt0 = 0;
  49.  
  50.         if(bt0 > 250)   bt0 = 255;
  51.         if(bt0 < 0)     bt0 = 0;
  52.  
  53.         if(rt1 > 250)   rt1 = 255;
  54.         if(rt1 < 0)     rt1 = 0;
  55.  
  56.         if(gt1 > 250)   gt1 = 255;
  57.         if(gt1 < 0)     gt1 = 0;
  58.  
  59.         if(bt1 > 250)   bt1 = 255;
  60.         if(bt1 < 0)     bt1 = 0;
  61.  
  62.         *r0 = (unsigned char)rt0;
  63.         *g0 = (unsigned char)gt0;
  64.         *b0 = (unsigned char)bt0;
  65.  
  66.         *r1 = (unsigned char)rt1;
  67.         *g1 = (unsigned char)gt1;
  68.         *b1 = (unsigned char)bt1;
  69.  
  70.         yuv = yuv + 4;
  71.         rgb = rgb + 6;
  72.         if(yuv == NULL)
  73.           break;
  74.  
  75.         y0 = yuv;
  76.         u0 = yuv + 1;
  77.         y1 = yuv + 2;
  78.         v0 = yuv + 3;
  79.  
  80.         r0 = rgb + 0;
  81.         g0 = rgb + 1;
  82.         b0 = rgb + 2;
  83.         r1 = rgb + 3;
  84.         g1 = rgb + 4;
  85.         b1 = rgb + 5;
  86.     }
  87. }
  88.  
  89. void CaptureThread::run()
  90. {
  91.     /* 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 */
  92. #ifdef linux
  93. #ifndef __arm__
  94.     return;
  95. #endif
  96.     int video_fd = -1;
  97.     struct v4l2_format fmt;
  98.     struct v4l2_requestbuffers req_bufs;
  99.     static struct v4l2_buffer buf;
  100.     int n_buf;
  101.     struct buffer_info bufs_info[VIDEO_BUFFER_COUNT];
  102.     enum v4l2_buf_type type;
  103.  
  104.     unsigned char src_buffer[WIDTH*HEIGHT*2];
  105.     unsigned char rgb_buffer[WIDTH*HEIGHT*2];
  106.  
  107.     video_fd = open(VIDEO_DEV, O_RDWR);
  108.     if (0 > video_fd) {
  109.         printf("ERROR: failed to open video device %s\n", VIDEO_DEV);
  110.         return ;
  111.     }
  112.  
  113.     fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  114.     fmt.fmt.pix.width = WIDTH;
  115.     fmt.fmt.pix.height = HEIGHT;
  116.     fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
  117.     fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
  118.  
  119.     if (0 > ioctl(video_fd, VIDIOC_S_FMT, &fmt)) {
  120.         printf("ERROR: failed to VIDIOC_S_FMT\n");
  121.         close(video_fd);
  122.         return ;
  123.     }
  124.  
  125.     if (0 > ioctl(video_fd, VIDIOC_G_FMT, &fmt)) {
  126.         printf("ERROR: failed to VIDIOC_S_FMT\n");
  127.         close(video_fd);
  128.         return ;
  129.     }
  130.     printf("fmt.type:\t\t%d\n",fmt.type);
  131.     printf("pix.pixelformat:\t%c%c%c%c\n", \
  132.             fmt.fmt.pix.pixelformat & 0xFF,\
  133.             (fmt.fmt.pix.pixelformat >> 8) & 0xFF, \
  134.             (fmt.fmt.pix.pixelformat >> 16) & 0xFF,\
  135.             (fmt.fmt.pix.pixelformat >> 24) & 0xFF);
  136.     printf("pix.width:\t\t%d\n",fmt.fmt.pix.width);
  137.     printf("pix.height:\t\t%d\n",fmt.fmt.pix.height);
  138.     printf("pix.field:\t\t%d\n",fmt.fmt.pix.field);
  139.  
  140.     req_bufs.count = VIDEO_BUFFER_COUNT;
  141.     req_bufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  142.     req_bufs.memory = V4L2_MEMORY_MMAP;
  143.  
  144.     if (0 > ioctl(video_fd, VIDIOC_REQBUFS, &req_bufs)) {
  145.         printf("ERROR: failed to VIDIOC_REQBUFS\n");
  146.         return ;
  147.     }
  148.  
  149.     buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  150.     buf.memory = V4L2_MEMORY_MMAP;
  151.     for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {
  152.  
  153.         buf.index = n_buf;
  154.         if (0 > ioctl(video_fd, VIDIOC_QUERYBUF, &buf)) {
  155.             printf("ERROR: failed to VIDIOC_QUERYBUF\n");
  156.             return ;
  157.         }
  158.  
  159.         bufs_info[n_buf].length = buf.length;
  160.         bufs_info[n_buf].start = mmap(NULL, buf.length,
  161.                                       PROT_READ | PROT_WRITE, MAP_SHARED,
  162.                                       video_fd, buf.m.offset);
  163.         if (MAP_FAILED == bufs_info[n_buf].start) {
  164.             printf("ERROR: failed to mmap video buffer, size 0x%x\n", buf.length);
  165.             return ;
  166.         }
  167.     }
  168.  
  169.     for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {
  170.  
  171.         buf.index = n_buf;
  172.         if (0 > ioctl(video_fd, VIDIOC_QBUF, &buf)) {
  173.             printf("ERROR: failed to VIDIOC_QBUF\n");
  174.             return ;
  175.         }
  176.     }
  177.  
  178.     type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
  179.     if (0 > ioctl(video_fd, VIDIOC_STREAMON, &type)) {
  180.         printf("ERROR: failed to VIDIOC_STREAMON\n");
  181.         return ;
  182.     }
  183.  
  184.     while (startFlag) {
  185.  
  186.         for (n_buf = 0; n_buf < VIDEO_BUFFER_COUNT; n_buf++) {
  187.  
  188.             buf.index = n_buf;
  189.  
  190.             //出队
  191.             if (0 > ioctl(video_fd, VIDIOC_DQBUF, &buf)) {
  192.                 printf("ERROR: failed to VIDIOC_DQBUF\n");
  193.                 return;
  194.             }
  195. //            printf("now memcpy the src buf, buf start=%d, len=%d\r\n", bufs_info[n_buf].start, bufs_info[n_buf].length);
  196.             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
  197.             yuyv_to_rgb((unsigned char*)bufs_info[n_buf].start, rgb_buffer);                            //yuyv转rgb
  198.             QImage qImage(rgb_buffer, fmt.fmt.pix.width, fmt.fmt.pix.height, QImage::Format_RGB16);     //显示到屏幕
  199. //            QImage qImage((unsigned char*)bufs_info[n_buf].start, fmt.fmt.pix.width, fmt.fmt.pix.height, QImage::Format_RGB16);
  200.  
  201.             /* 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 */
  202.             if (startLocalDisplay)
  203.                 emit imageReady(qImage);
  204.  
  205.             /* 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 */
  206.             if (startBroadcast) {
  207.                 /* udp套接字 */
  208.                 QUdpSocket udpSocket;
  209.  
  210.                 /* QByteArray类型 */
  211.                 QByteArray byte;
  212.  
  213.                 /* 建立一个用于IO读写的缓冲区 */
  214.                 QBuffer buff(&byte);
  215.  
  216.                 /* image转为byte的类型，再存入buff */
  217.                 qImage.save(&buff, "JPEG", -1);
  218.  
  219.                 /* 转换为base64Byte类型 */
  220.                 QByteArray base64Byte = byte.toBase64();
  221.  
  222.                 /* 由udpSocket以广播的形式传输数据，端口号为8888 */
  223.                 udpSocket.writeDatagram(base64Byte.data(), base64Byte.size(), QHostAddress::Broadcast, 8888);
  224.             }
  225.  
  226.             //入队
  227.             if (0 > ioctl(video_fd, VIDIOC_QBUF, &buf)) {
  228.                 printf("ERROR: failed to VIDIOC_QBUF\n");
  229.                 return;
  230.             }
  231.         }
  232.     }
  233.  
  234.     msleep(800);//at lease 650
  235.  
  236.     for (int i = 0; i < VIDEO_BUFFER_COUNT; i++) {
  237.         munmap(bufs_info[i].start, buf.length);
  238.     }
  239.  
  240.     close(video_fd);
  241. #endif
  242. }

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