settings.cpp Example File
cameracapture/settings.cpp

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    #include "settings.h"
    #include "ui_settings.h"

    #include <QtGui/qcombobox.h>
    #include <QtCore/qdebug.h>
    #include <qmediarecorder.h>
    #include <qmediaservice.h>

    Settings::Settings(QMediaRecorder *mediaRecorder, QWidget *parent) :
        QDialog(parent),
        ui(new Ui::Settings),
        mediaRecorder(mediaRecorder)
    {
        ui->setupUi(this);

        //audio codecs
        foreach(const QString &codecName, mediaRecorder->supportedAudioCodecs()) {
            QString description = mediaRecorder->audioCodecDescription(codecName);
            ui->audioCodecBox->addItem(codecName+": "+description, QVariant(codecName));
        }

        //sample rate:
        foreach(int sampleRate, mediaRecorder->supportedAudioSampleRates()) {
            ui->audioSampleRateBox->addItem(QString::number(sampleRate), QVariant(sampleRate));
        }

        ui->audioQualitySlider->setRange(0, int(QtMedia::VeryHighQuality));

        //video codecs
        foreach(const QString &codecName, mediaRecorder->supportedVideoCodecs()) {
            QString description = mediaRecorder->videoCodecDescription(codecName);
            ui->videoCodecBox->addItem(codecName+": "+description, QVariant(codecName));
        }

        ui->videoQualitySlider->setRange(0, int(QtMedia::VeryHighQuality));

        ui->videoResolutionBox->addItem(tr("Default"));
        QList<QSize> supportedResolutions = mediaRecorder->supportedResolutions();
        foreach(const QSize &resolution, supportedResolutions) {
            ui->videoResolutionBox->addItem(QString("%1x%2").arg(resolution.width()).arg(resolution.height()),
                                            QVariant(resolution));
        }

        ui->videoFramerateBox->addItem(tr("Default"));
        QList<qreal> supportedFrameRates = mediaRecorder->supportedFrameRates();
        qreal rate;
        foreach(rate, supportedFrameRates) {
            QString rateString = QString("%1").arg(rate, 0, 'f', 2);
            ui->videoFramerateBox->addItem(rateString, QVariant(rate));
        }

        //containers
        foreach(const QString &format, mediaRecorder->supportedFormats()) {
            ui->containerFormatBox->addItem(format+":"+mediaRecorder->formatDescription(format),
                                            QVariant(format));
        }
    }

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

    void Settings::changeEvent(QEvent *e)
    {
        QDialog::changeEvent(e);
        switch (e->type()) {
        case QEvent::LanguageChange:
            ui->retranslateUi(this);
            break;
        default:
            break;
        }
    }

    QAudioEncoderSettings Settings::audioSettings() const
    {
        QAudioEncoderSettings settings = mediaRecorder->audioSettings();
        settings.setCodec(boxValue(ui->audioCodecBox).toString());
        settings.setQuality(QtMedia::EncodingQuality(ui->audioQualitySlider->value()));
        settings.setSampleRate(boxValue(ui->audioSampleRateBox).toInt());
        return settings;
    }

    void Settings::setAudioSettings(const QAudioEncoderSettings &audioSettings)
    {
        selectComboBoxItem(ui->audioCodecBox, QVariant(audioSettings.codec()));
        selectComboBoxItem(ui->audioSampleRateBox, QVariant(audioSettings.sampleRate()));
        ui->audioQualitySlider->setValue(audioSettings.quality());
    }

    QVideoEncoderSettings Settings::videoSettings() const
    {
        QVideoEncoderSettings settings = mediaRecorder->videoSettings();
        settings.setCodec(boxValue(ui->videoCodecBox).toString());
        settings.setQuality(QtMedia::EncodingQuality(ui->videoQualitySlider->value()));
        settings.setResolution(boxValue(ui->videoResolutionBox).toSize());
        settings.setFrameRate(boxValue(ui->videoFramerateBox).value<qreal>());

        return settings;
    }

    void Settings::setVideoSettings(const QVideoEncoderSettings &videoSettings)
    {
        selectComboBoxItem(ui->videoCodecBox, QVariant(videoSettings.codec()));
        selectComboBoxItem(ui->videoResolutionBox, QVariant(videoSettings.resolution()));
        ui->videoQualitySlider->setValue(videoSettings.quality());

        //special case for frame rate
        for (int i=0; i<ui->videoFramerateBox->count(); i++) {
            qreal itemRate = ui->videoFramerateBox->itemData(i).value<qreal>();
            if (qFuzzyCompare(itemRate, videoSettings.frameRate())) {
                ui->videoFramerateBox->setCurrentIndex(i);
                break;
            }
        }
    }

    QString Settings::format() const
    {
        return boxValue(ui->containerFormatBox).toString();
    }

    void Settings::setFormat(const QString &format)
    {
        selectComboBoxItem(ui->containerFormatBox, QVariant(format));
    }

    QVariant Settings::boxValue(const QComboBox *box) const
    {
        int idx = box->currentIndex();
        if (idx == -1)
            return QVariant();

        return box->itemData(idx);
    }

    void Settings::selectComboBoxItem(QComboBox *box, const QVariant &value)
    {
        for (int i=0; i<box->count(); i++) {
            if (box->itemData(i) == value) {
                box->setCurrentIndex(i);
                break;
            }
        }
    }