Audio Recorder Example¶
Discovering the available devices and supported codecs.
Audio Recorder demonstrates how to identify the available devices and supported codecs, and the use of
Running the Example¶
To run the example from Qt Creator , open the Welcome mode and select the example from Examples . For more information, visit Building and Running an Example.
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
supportedAudioSampleRates()methods. The quality slider is setup from 0 (zero) to
VeryHighQualitywith a default value of
NormalQuality, while the bitrates are hardcoded into the list.
To record audio we simply create a
QAudioRecorderobject.audioRecorder = new QAudioRecorder(this);
And setup the lists as described above. The text on the record and pause buttons are toggled depending on the
audioRecorderobject. This means that if the state is
StoppedStatethen the button text will be “Record” and “Pause”. In
RecordingStatethe record button will have the text “Stop”, and in
PausedStatethe 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
QAudioEncoderSettingsbased on the values of the selection lists, will set the encoding settings and container on the
audioRecorderobject, and start recording using the
record()method.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();
While recording, the status bar of the application is updated with duration information from the
durationChangedsignal from the
audioRecorderobject.ui->statusbar->showMessage(tr("Recorded %1 sec").arg(duration / 1000));
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