15多媒体功能概述

多媒体概述

音频播放

#include    <QMediaPlayer>
#include    <QMediaPlaylist>
QMediaPlayer    *player= new QMediaPlayer(this);//播放器
QMediaPlaylist  *playlistnew QMediaPlaylist(this);//播放列表
playlist->setPlaybackMode(QMediaPlaylist::Loop); //循环模式
player->setPlaylist(playlist);
playlist->addMedia(QUrl::fromLocalFile(aFile));//添加文件
playlist->setCurrentIndex(Pos);
//播放
    player->play();
//暂停播放
    player->pause();
//停止播放
    player->stop();
//调整音量
    player->setVolume(value);

void MainWindow::on_btnSound_clicked()
{//静音控制
    bool mute=player->isMuted();
    player->setMuted(!mute);
    if (mute)
        ui->btnSound->setIcon(QIcon(":/images/images/volumn.bmp"));
    else
        ui->btnSound->setIcon(QIcon(":/images/images/mute.bmp"));
}
//文件进度调控
   player->setPosition(value);
}
//前一文件
    playlist->previous();
//下一文件
    playlist->next();

QAudioRecorder录制音频

#include    <QAudioRecorder>
#include    <QAudioProbe>
QAudioRecorder *recorder= new QAudioRecorder(this);//音频录音
QAudioProbe *probe= new QAudioProbe; //探测器
probe->setSource(recorder);
if (recorder->defaultAudioInput().isEmpty())
   return;  //无音频录入设备
recorder->audioInputs();//音频录入设备列表
recorder->supportedAudioCodecs();//支持的音频编码
recorder->supportedAudioSampleRates();//支持的采样率
QMultimedia::VeryHighQuality;//Enum

void MainWindow::onDurationChanged(qint64 duration)
{//录音持续时间变化
    ui->LabPassTime->setText(QString("已录制 %1 秒").arg(duration / 1000));
}

void MainWindow::processBuffer(const QAudioBuffer &buffer)
{ //处理探测到的缓冲区
    ui->spin_byteCount->setValue(buffer.byteCount());//缓冲区字节数
    ui->spin_duration->setValue(buffer.duration()/1000);//缓冲区时长
    ui->spin_frameCount->setValue(buffer.frameCount());//缓冲区帧数
    ui->spin_sampleCount->setValue(buffer.sampleCount());//缓冲区采样数

    QAudioFormat audioFormat=buffer.format();//缓冲区格式
    ui->spin_channelCount->setValue(audioFormat.channelCount()); //通道数
    ui->spin_sampleSize->setValue(audioFormat.sampleSize());//采样大小
    ui->spin_sampleRate->setValue(audioFormat.sampleRate());//采样率
    ui->spin_bytesPerFrame->setValue(audioFormat.bytesPerFrame());//每帧字节数

    if (audioFormat.byteOrder()==QAudioFormat::LittleEndian)
        ui->edit_byteOrder->setText("LittleEndian");//字节序
    else
        ui->edit_byteOrder->setText("BigEndian");

    ui->edit_codec->setText(audioFormat.codec());//编码格式

    if (audioFormat.sampleType()==QAudioFormat::SignedInt)//采样点类型
}

recorder->setOutputLocation(QUrl::fromLocalFile(selectedFile));//设置输出文件
recorder->setAudioInput(ui->comboDevices->currentText()); //设置录入设备
QAudioEncoderSettings settings; //音频编码设置
settings.setCodec(ui->comboCodec->currentText());//编码
settings.setSampleRate(ui->comboSampleRate->currentText().toInt());//采样率
settings.setBitRate(ui->comboBitrate->currentText().toInt());//比特率
settings.setChannelCount(ui->comboChannels->currentText().toInt()); //通道数
settings.setQuality(QMultimedia::EncodingQuality(ui->sliderQuality->value())); //品质
//编码模式为固定品质,自动决定采样率，采样点大小
settings.setEncodingMode(QMultimedia::ConstantQualityEncoding);
settings.setEncodingMode(QMultimedia::ConstantBitRateEncoding);//固定比特率
recorder->setAudioSettings(settings); //音频设置
//开始录音
recorder->record();
//暂停
recorder->pause();
//停止
recorder->stop();

QAudioInput获取音频输入

在QVideoWidget上播放视频

//在ui中加入一个QWidget 自己写一个类，继承自QVideoWidget 并进行提升
//QmyVideoWidget.h
#include    <QObject>
#include    <QWidget>
#include    <QVideoWidget>
#include    <QMediaPlayer>

class QmyVideoWidget : public QVideoWidget
{
private:
    QMediaPlayer    *thePlayer;//

protected:
    void keyPressEvent(QKeyEvent *event);

    void mousePressEvent(QMouseEvent *event);

public:
    QmyVideoWidget(QWidget *parent = Q_NULLPTR);

    void    setMediaPlayer(QMediaPlayer *player);
};

//QmyVideoWidget.cpp
#include "qmyvideowidget.h"
#include    <QKeyEvent>
#include    <QMouseEvent>

void QmyVideoWidget::keyPressEvent(QKeyEvent *event)
{//按键事件，ESC退出全屏状态
    if ((event->key() == Qt::Key_Escape)&&(isFullScreen()))
    {
        setFullScreen(false);
        event->accept();
        QVideoWidget::keyPressEvent(event);
    }
}
void QmyVideoWidget::mousePressEvent(QMouseEvent *event)
{//鼠标事件，单击控制暂停和继续播放
    if (event->button()==Qt::LeftButton)
    {
        if (thePlayer->state()==QMediaPlayer::PlayingState)
          thePlayer->pause();
        else
          thePlayer->play();
    }
    QVideoWidget::mousePressEvent(event);

}
void QmyVideoWidget::setMediaPlayer(QMediaPlayer *player)
{//设置播放器
    thePlayer=player;
}

#include    <QMediaPlayer>
#include    <QMediaPlaylist>
#include    <QVideoWidget>
player = new QMediaPlayer(this);//创建视频播放器
player->setNotifyInterval(2000);//信息更新周期
player->setVideoOutput(ui->videoWidget);//视频显示组件
ui->videoWidget->setMediaPlayer(player);//设置显示组件的关联播放器
    player->setMedia(QUrl::fromLocalFile(aFile));//设置播放文件
    player->play();

//暂停
    player->pause();
//停止
    player->stop();
//调节音量
    player->setVolume(value);

void MainWindow::on_btnSound_clicked()
{//静音按钮
    bool mute=player->isMuted();
    player->setMuted(!mute);
    if (mute)
        ui->btnSound->setIcon(QIcon(":/images/images/volumn.bmp"));
    else
        ui->btnSound->setIcon(QIcon(":/images/images/mute.bmp"));
}
//播放位置
   player->setPosition(value);
//全屏按钮
    ui->videoWidget->setFullScreen(true);

在QGraphicsVideoItem上播放视频

这种视频可以任意拖拽位置（非播放进度）

#include    <QMediaPlayer>
#include    <QMediaPlaylist>
#include    <QVideoWidget>
#include    <QGraphicsVideoItem>
#include    <QGraphicsScene>

QGraphicsScene *scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

QMediaPlayer    *player= new QMediaPlayer(this);
QGraphicsVideoItem *videoItem= new QGraphicsVideoItem;
videoItem->setSize(QSizeF(360, 240));
videoItem->setFlags(QGraphicsItem::ItemIsMovable| QGraphicsItem::ItemIsSelectable
                   | QGraphicsItem::ItemIsFocusable);
scene->addItem(videoItem);
player->setVideoOutput(videoItem);//设置视频显示图形组件

摄像头的使用

#include    <QCameraInfo>
#include    <QCamera>
#include    <QCameraViewfinder>
#include    <QCameraImageCapture>
#include    <QMediaRecorder>
#include    <QSoundEffect>
#include    <QSound>


QCameraInfo curCameraInfo=QCameraInfo::defaultCamera(); //获取缺省摄像头
QCamera     *curCamera==new QCamera(curCameraInfo,this); //创建摄像头对象
QCameraViewfinderSettings viewfinderSettings;
viewfinderSettings.setResolution(640, 480);
curCamera->setViewfinder(ui->viewFinder); //设置取景框预览 这就是个widget
curCamera->setCaptureMode(QCamera::CaptureStillImage);//设置为抓图

//curCamera->isCaptureModeSupported(QCamera::CaptureStillImage) 是否支持抓图
QCameraImageCapture *imageCapture=new QCameraImageCapture(curCamera,this); //抓图
imageCapture->setBufferFormat(QVideoFrame::Format_Jpeg); //缓冲区格式
imageCapture->setCaptureDestination(QCameraImageCapture::CaptureToFile); //保存目标

curCamera->start();//开启摄像头
curCamera->stop();//关闭摄像头
QSound::play(filename); //播放快门音效

QMediaRecorder* mediaRecorder=new QMediaRecorder(curCamera,this);//录像
mediaRecorder->setOutputLocation(QUrl::fromLocalFile(selectedFile));
mediaRecorder->record();
//停止录像
mediaRecorder->stop();