骤：
1.录屏
思路：子线程进行截屏的方式进行录制，再使用avilib将截取到的图片保存为视频文件。
参考文章：avilib库的使用 - Ron's个人页面 - OSCHINA - 中文开源技术交流社区
子线程录制通过上文中的ToAviThread来实现
void ToAviThread::run(){QScreen *screen = QApplication::primaryScreen();QDesktopWidget* desktopWidget = QApplication::desktop();QRect screenRect = desktopWidget->screenGeometry();//设置保存路径out_fd = AVI_open_output_file(toAviFilePath.toLocal8Bit().data());if(out_fd == NULL){qDebug()<<"open file erro";}//size根据自身情况来设置，这里是之前保存过的一个变量，其实和上面的screenRect是一样的QSize size = GNConfig::getInstance()->getMainSize();//avilib设置尺寸帧率和格式AVI_set_video(out_fd, size.width(), size.height(), 6, "mjpg");//设置视频文件的格式while(!stopFlag){//pause逻辑sync.lock();if(is_pause){pauseCond.wait(&sync); // in this place, your thread will stop to execute until someone calls resume}sync.unlock();//进行屏幕抓取// if(frameBuffer != NULL && bytes !=0){QPixmap map = this->grabWindow((HWND)QApplication::desktop()->winId(), 0, 0, screenRect.width(), screenRect.height());//抓取到的pixmap保存为bytearrayQByteArray ba;QBuffer bf(&ba);if (!map.save(&bf, "jpg", 50))exit(0);frameBuffer = ba.data();bytes = ba.length();//每次截屏是1帧，写入到视频文件里if(AVI_write_frame(out_fd,frameBuffer,bytes,1)<0)//向视频文件中写入一帧图像{qDebug()<<"write erro";}else{frameBuffer = NULL;bytes = 0;}}}//截屏完成，保存到文件中AVI_close (out_fd); //关闭文件描述符，并保存文件}
线程stop后，通过AVI_close保存到之前设置的路径中，至此视频录制完成。假如
AVI_open_output_file里设置的是e:\test.avi，那AVI_close后此文件就会自动生成。
PS:这里说明一下，之所以
AVI_set_video(out_fd, size.width(), size.height(), 6, "mjpg");
设置的是6帧，其实是因为每秒grab屏幕最快也就是6张，再多了录制的时间会对应不上。
另外grab函数自己重写了，也是参考网上的，QScreen的grabwindow方法无法抓取鼠标，所以baidu了一下。代码如下：
QPixmap ToAviThread::grabWindow(HWND winId, int x, int y, int w, int h){RECT r;GetClientRect(winId, &r);if (w < 0) w = r.right - r.left;if (h < 0) h = r.bottom - r.top;HDC display_dc = GetDC(winId);HDC bitmap_dc = CreateCompatibleDC(display_dc);HBITMAP bitmap = CreateCompatibleBitmap(display_dc, w, h);HGDIOBJ null_bitmap = SelectObject(bitmap_dc, bitmap);BitBlt(bitmap_dc, 0, 0, w, h, display_dc, x, y, SRCCOPY | CAPTUREBLT);CURSORINFO ci;ci.cbSize = sizeof(CURSORINFO);GetCursorInfo(&ci);if((ci.ptScreenPos.x > x) && (ci.ptScreenPos.y > y) && (ci.ptScreenPos.x < (x+w)) && (ci.ptScreenPos.y < (y+h)))DrawIcon(bitmap_dc, ci.ptScreenPos.x-x, ci.ptScreenPos.y-y, ci.hCursor);// clean up all but bitmapReleaseDC(winId, display_dc);SelectObject(bitmap_dc, null_bitmap);DeleteDC(bitmap_dc);QPixmap pixmap = QtWin::fromHBITMAP(bitmap);DeleteObject(bitmap);return pixmap;}
2.录音
思路：使用QAudioInput进行麦克风设备的检测，录音采用QAudioRecorder来实现。
先来说音频设备检测：
窗体代码
#ifndef GNDEVICEDLG_H#define GNDEVICEDLG_H#include "GNIODevice.h"#include <QMouseEvent>#include <QWidget>#include <QAudioRecorder>#include <QAudioInput>namespace Ui {class GNDeviceDlg;}class GNDeviceDlg : public QWidget{Q_OBJECTpublic:explicit GNDeviceDlg(QWidget *parent = 0);~GNDeviceDlg();void showDeviceTest(QWidget* parent);private slots:void on_btnStartTest_clicked();void onSkip();void on_btnOK_clicked();void on_btnReTest_clicked();void refreshDisplay();void onGotoResultPage();signals:void showRecordView(const QString& deviceName);protected:void mousePressEvent(QMouseEvent *event);void mouseReleaseEvent(QMouseEvent *event);void mouseMoveEvent(QMouseEvent *event);private:void initAudioRecorder();enum{PAGE_DEFAULT,PAGE_TESTING,PAGE_PASS,PAGE_WRONG};private:Ui::GNDeviceDlg *ui;bool bPressFlag;QPoint beginDrag;QAudioRecorder *audioRecorder = NULL;QAudioInput* m_audioInput = NULL;GNIODevice* m_device = NULL;QAudioFormat formatAudio;bool bTestPass=false;};#endif // GNDEVICEDLG_H
#include "GNDeviceDlg.h"#include "ui_GNDeviceDlg.h"#include <GNTipMessageBox.h>#include <QDebug>#include <QFileInfo>#include <QListView>#include <QTimer>GNDeviceDlg::GNDeviceDlg(QWidget *parent) :QWidget(parent),ui(new Ui::GNDeviceDlg){ui->setupUi(this);setWindowFlags(Qt::Tool |Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint | Qt::Dialog);setWindowModality(Qt::ApplicationModal);this->setAttribute(Qt::WA_TranslucentBackground);this->setAttribute(Qt::WA_DeleteOnClose);connect(ui->labelSkip, &GNClickableLabel::clicked, this, &GNDeviceDlg::onSkip);connect(ui->labelSkip_2, &GNClickableLabel::clicked, this, &GNDeviceDlg::onSkip);ui->stackedWidget->setCurrentIndex(PAGE_DEFAULT);qDebug()<<"[GNDeviceDlg] new QAudioRecorder";audioRecorder = new QAudioRecorder(this);//设置音频格式formatAudio.setSampleRate(8000);formatAudio.setChannelCount(1);formatAudio.setSampleSize(16);formatAudio.setSampleType(QAudioFormat::SignedInt);formatAudio.setByteOrder(QAudioFormat::LittleEndian);formatAudio.setCodec("audio/pcm");QAudioDeviceInfo defaultInfo = QAudioDeviceInfo::defaultInputDevice();//初始化检测音频设备的input对象m_audioInput = new QAudioInput(defaultInfo,formatAudio, this);m_device = new GNIODevice(formatAudio, this);connect(m_device, SIGNAL(update()), SLOT(refreshDisplay()));ui->comboBox->setEnabled(true);ui->comboBox->setView(new QListView());}GNDeviceDlg::~GNDeviceDlg(){delete ui;}void GNDeviceDlg::initAudioRecorder(){QStringList inputs = audioRecorder->audioInputs();qDebug()<<"initAudioRecorder inputs:"<<inputs;ui->comboBox->clear();ui->comboBox->addItems(inputs);}//开始检测按钮void GNDeviceDlg::on_btnStartTest_clicked(){if(ui->comboBox->currentText().isEmpty()){//自定义msgbox，可用qmessagebox替换GNTipMessageBox tipBox;tipBox.updateMsg(tr("tip"), tr("Current no micphone device, Please plugin!"), tr("ok"));tipBox.exec();return;}ui->comboBox->setEnabled(false);qDebug()<<"start test device name:"<<ui->comboBox->currentText();//遍历音频输入设备列表QAudioDeviceInfo testInfo;QList<QAudioDeviceInfo> infos = QAudioDeviceInfo::availableDevices(QAudio::AudioInput);foreach (QAudioDeviceInfo info, infos) {qDebug()<<"info:"<<info.deviceName();//打印现有电脑上的麦克风设备if(info.deviceName() == ui->comboBox->currentText()){testInfo = info;break;}}if(m_audioInput){m_audioInput->stop();delete m_audioInput;m_audioInput = new QAudioInput(testInfo,formatAudio, this);}m_device->start();m_audioInput->start(m_device);ui->stackedWidget->setCurrentIndex(PAGE_TESTING);bTestPass = false;QTimer::singleShot(5000, this, SLOT(onGotoResultPage()));}//跳过检测void GNDeviceDlg::onSkip(){this->hide();m_device->stop();m_audioInput->stop();emit showRecordView(ui->comboBox->currentText());}void GNDeviceDlg::on_btnOK_clicked(){this->hide();m_device->stop();m_audioInput->stop();//显示录制窗体emit showRecordView(ui->comboBox->currentText());}void GNDeviceDlg::on_btnReTest_clicked(){on_btnStartTest_clicked();}void GNDeviceDlg::onGotoResultPage(){m_device->stop();m_audioInput->stop();ui->comboBox->setEnabled(true);if(bTestPass){ui->stackedWidget->setCurrentIndex(PAGE_PASS);//检测成功}else{ui->stackedWidget->setCurrentIndex(PAGE_WRONG);//检测失败}}void GNDeviceDlg::refreshDisplay(){int value = m_device->level()*100;qDebug()<<"level:"<<m_device->level()<<" value:"<<value;ui->progressBar->setValue(value);if(value>0){bTestPass=true;}}void GNDeviceDlg::showDeviceTest(QWidget* parentBtn){initAudioRecorder();QPoint GlobalPoint(parentBtn->mapToGlobal(QPoint(0, 0)));qWarning()<<"parentBtn pos:"<<parentBtn->pos()<<" GlobalPoint:"<<GlobalPoint;int x = GlobalPoint.x() - this->width()/2 + parentBtn->width()/2;int y = GlobalPoint.y() - this->height()-20;this->move(x, y);ui->stackedWidget->setCurrentIndex(PAGE_DEFAULT);ui->comboBox->setEnabled(true);this->show();}void GNDeviceDlg::mousePressEvent(QMouseEvent *event){bPressFlag = true;beginDrag = event->pos();QWidget::mousePressEvent(event);}void GNDeviceDlg::mouseReleaseEvent(QMouseEvent *event){bPressFlag = false;QWidget::mouseReleaseEvent(event);}void GNDeviceDlg::mouseMoveEvent(QMouseEvent *event){if (bPressFlag){QPoint relaPos(QCursor::pos() - beginDrag);move(relaPos);}QWidget::mouseMoveEvent(event);}
使用QAudioInput进行麦克风音量的检测，核心是继承QIODevice，然后在writeData虚函数里对音频数据进行音量的判断。
如下：
#ifndef GNIODEVICE_H#define GNIODEVICE_H#include <QtCore/QIODevice>#include <QAudioFormat>class GNIODevice: public QIODevice{Q_OBJECTpublic:GNIODevice(const QAudioFormat &format, QObject *parent);~GNIODevice();void start();void stop();qreal level() const { return m_level; }qint64 readData(char *data, qint64 maxlen);qint64 writeData(const char *data, qint64 len);private:const QAudioFormat m_format;quint32 m_maxAmplitude;qreal m_level; // 0.0 <= m_level <= 1.0signals:void update();};#endif // GNIODEVICE_H
#include "GNIODevice.h"#include <QDebug>#include <QtEndian>const int BufferSize = 4096;GNIODevice::GNIODevice(const QAudioFormat &format, QObject *parent): QIODevice(parent),m_format(format),m_maxAmplitude(0),m_level(0.0){switch (m_format.sampleSize()) {case 8:switch (m_format.sampleType()) {case QAudioFormat::UnSignedInt:m_maxAmplitude = 255;break;case QAudioFormat::SignedInt:m_maxAmplitude = 127;break;default:break;}break;case 16:switch (m_format.sampleType()) {case QAudioFormat::UnSignedInt:m_maxAmplitude = 65535;break;case QAudioFormat::SignedInt:m_maxAmplitude = 32767;break;default:break;}break;case 32:switch (m_format.sampleType()) {case QAudioFormat::UnSignedInt:m_maxAmplitude = 0xffffffff;break;case QAudioFormat::SignedInt:m_maxAmplitude = 0x7fffffff;break;case QAudioFormat::Float:m_maxAmplitude = 0x7fffffff; // Kind ofdefault:break;}break;default:break;}}GNIODevice::~GNIODevice(){}void GNIODevice::start(){open(QIODevice::WriteOnly);}void GNIODevice::stop(){close();}qint64 GNIODevice::writeData(const char *data, qint64 len){if (m_maxAmplitude) {Q_ASSERT(m_format.sampleSize() % 8 == 0);const int channelBytes = m_format.sampleSize() / 8;const int sampleBytes = m_format.channelCount() * channelBytes;Q_ASSERT(len % sampleBytes == 0);const int numSamples = len / sampleBytes;quint32 maxValue = 0;const unsigned char *ptr = reinterpret_cast<const unsigned char *>(data);for (int i = 0; i < numSamples; ++i) {for (int j = 0; j < m_format.channelCount(); ++j) {quint32 value = 0;if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::UnSignedInt) {value = *reinterpret_cast<const quint8*>(ptr);} else if (m_format.sampleSize() == 8 && m_format.sampleType() == QAudioFormat::SignedInt) {value = qAbs(*reinterpret_cast<const qint8*>(ptr));} else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::UnSignedInt) {if (m_format.byteOrder() == QAudioFormat::LittleEndian)value = qFromLittleEndian<quint16>(ptr);elsevalue = qFromBigEndian<quint16>(ptr);} else if (m_format.sampleSize() == 16 && m_format.sampleType() == QAudioFormat::SignedInt) {if (m_format.byteOrder() == QAudioFormat::LittleEndian)value = qAbs(qFromLittleEndian<qint16>(ptr));elsevalue = qAbs(qFromBigEndian<qint16>(ptr));} else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::UnSignedInt) {if (m_format.byteOrder() == QAudioFormat::LittleEndian)value = qFromLittleEndian<quint32>(ptr);elsevalue = qFromBigEndian<quint32>(ptr);} else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::SignedInt) {if (m_format.byteOrder() == QAudioFormat::LittleEndian)value = qAbs(qFromLittleEndian<qint32>(ptr));elsevalue = qAbs(qFromBigEndian<qint32>(ptr));} else if (m_format.sampleSize() == 32 && m_format.sampleType() == QAudioFormat::Float) {value = qAbs(*reinterpret_cast<const float*>(ptr) * 0x7fffffff); // assumes 0-1.0}maxValue = qMax(value, maxValue);ptr += channelBytes;}}maxValue = qMin(maxValue, m_maxAmplitude);m_level = qreal(maxValue) / m_maxAmplitude;}emit update();return len;}qint64 GNIODevice::readData(char *data, qint64 maxlen){Q_UNUSED(data)Q_UNUSED(maxlen)return 0;}
其中的m_level对应的就是音量大小了。直接用来检测声音。只不过需要注意的是level是从0-1.
3.最后来说合成
思路：使用ffmpeg进行音视频合成
这部就比较简单了，先去下载ffmpeg，/builds/
这里把share下载下来即可，里面是编译好的ffmpeg，我们直接通过ffmpeg.exe命令行的方式调用合成功能。
合成代码：
void GNCompressView::startCompress(QString wav, QString avi, QString outName){QString program = qApp->applicationDirPath();program += "/compress/ffmpeg.exe";QProcess process(this);connect(&process, static_cast<void(QProcess::*)(int, QProcess::ExitStatus)>(&QProcess::finished), this, &GNCompressView::onFinished);QStringList arguments;if(!wav.isEmpty()){arguments<<"-i"<<wav<<"-i"<<avi<<outName;//传递到exe的参数}else{//没有音频，只把avi转成MP4arguments<<"-i"<<avi<<"-vcodec"<<"mpeg4"<<outName;}process.start(program, arguments);}void GNCompressView::onFinished(int exitCode, QProcess::ExitStatus exitStatus){qDebug()<<"onFinished exitCode:"<<exitCode<<" exitStatus:"<<exitStatus;isFinished = true;emit compressSuccessed();}
其实就是调用命令行，把下载的ffmpeg的share里bin目录中的内容拷贝到工程运行目录下，代码里直接通过QProcess调用ffmpeg.exe。
合成命令其实就是ffmpeg -i my.wav -i my.avi out.mp4，将avi和wav合并为mp4，至于其他编码设置，自行baidu一下ffmpeg用法即可，这里不做赘述。
总结：到这里音频检测+录音，以及录制屏幕视频和最终的合成全部完成。Baidu了很多，开始想把ffmpeg代码直接弄到工程下，后来由于环境原因就采取了外部调用ffmpeg的方式，不过效果达到了。也欢迎大家留意交流。如果在录制屏幕这块有更高效，帧率更高的的方法，也请告知。
