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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Free Documentation License Usage
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of
** this file. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\example multimedia/audiorecorder
\title Audio Recorder Example
\ingroup multimedia_examples
\brief Discovering the available devices and supported codecs.
\meta {tag} {widgets}
\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, sample rate, and channels. It allows setting of either
quality or bit rate. Finally, the output file can be selected and recording
can be started.
The lists are populated using the following methods:
\list
\li \l{QMediaDevices::audioInputs()}
\li \l{QMediaFormat::supportedAudioCodecs}
\li \l{QMediaFormat::supportedFileFormats}
\li \l{QAudioDevice::maximumSampleRate()}
\li \l{QAudioDevice::minimumSampleRate()}
\endlist
The quality slider is setup from 0 (zero) to
\l{QMediaRecorder::VeryHighQuality} with a default value of
\l{QMediaRecorder::NormalQuality}, while the bit rate box are hard-coded
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::RecorderState}{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
QMediaFormat format;
format.setCodec(boxValue(ui->audioCodecBox).toString());
audioRecorder->setMediaFormat(format);
audioRecorder->setSampleRate(boxValue(ui->sampleRateBox).toInt());
audioRecorder->setBitRate(boxValue(ui->bitrateBox).toInt());
audioRecorder->setQuality(QMediaRecorder::EncodingQuality(ui->qualitySlider->value()));
audioRecorder->setEncodingMode(ui->constantQualityRadioButton->isChecked() ?
QMediaRecorder::ConstantQualityEncoding :
QMediaRecorder::ConstantBitRateEncoding);
QString container = boxValue(ui->containerBox).toString();
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
*/
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