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/*!
    \example multimedia/audiorecorder
    \title Audio Recorder Example
    \ingroup multimedia_examples
    \brief Discovering the available devices and supported codecs.

    \e{Audio Recorder} demonstrates how to identify the available devices and
    supported codecs, and the use of QAudioRecorder class.

    \image audiorecorder.png

    \include examples-run.qdocinc

    \section1 Displaying the Window and Audio Settings

    We display a window for the user to select the appropriate audio input,
    codec, container, and sample rate. Allow a setting of either quality or
    bitrate. Finally, the output file can be selected and recording can be
    started.

    The lists are setup using the \l{QAudioRecorder::audioInputs()}{audioInputs()},
    \l{QAudioRecorder::supportedAudioCodecs()}{supportedAudioCodecs()},
    \l{QAudioRecorder::supportedContainers()}{supportedContainers()},
    \l{QAudioRecorder::supportedContainers()}{supportedContainers()}, and
    \l{QAudioRecorder::supportedAudioSampleRates()}{supportedAudioSampleRates()}
    methods. The quality slider is setup from 0 (zero) to
    \l{QMultimedia::VeryHighQuality} with a default value of
    \l{QMultimedia::NormalQuality}, while the bitrates are hardcoded
    into the list.

    \section1 Recording Audio

    To record audio we simply create a QAudioRecorder object.

    \code
    audioRecorder = new QAudioRecorder(this);
    \endcode

    And setup the lists as described above. The text on the record and pause
    buttons are toggled depending on the \l{QMediaRecorder::State}{state} of
    the \c audioRecorder object. This means that if the state is
    \l{QMediaRecorder::StoppedState} then the button text will be "Record" and
    "Pause". In \l{QMediaRecorder::RecordingState} the record button will have
    the text "Stop", and in \l{QMediaRecorder::PausedState} the pause button
    will have the text "Resume".

    Pressing the buttons will also result in a toggle based on the state. If
    recording is stopped, then pressing the record button will setup the
    \l{QAudioEncoderSettings} based on the values of the selection lists,
    will set the encoding settings and container on the \c audioRecorder
    object, and start recording using the
    \l{QMediaRecorder::record()}{record()} method.

    \code
        QAudioEncoderSettings settings;
        settings.setCodec(boxValue(ui->audioCodecBox).toString());
        settings.setSampleRate(boxValue(ui->sampleRateBox).toInt());
        settings.setBitRate(boxValue(ui->bitrateBox).toInt());
        settings.setQuality(QMultimedia::EncodingQuality(ui->qualitySlider->value()));
        settings.setEncodingMode(ui->constantQualityRadioButton->isChecked() ?
                                 QMultimedia::ConstantQualityEncoding :
                                 QMultimedia::ConstantBitRateEncoding);

        QString container = boxValue(ui->containerBox).toString();

        audioRecorder->setEncodingSettings(settings, QVideoEncoderSettings(), container);
        audioRecorder->record();
    \endcode

    While recording, the status bar of the application is updated with duration information
    from the \l{QMediaRecorder::durationChanged()}{durationChanged} signal from the
    \c audioRecorder object.

    \code
    ui->statusbar->showMessage(tr("Recorded %1 sec").arg(duration / 1000));
    \endcode
*/