The QMediaRecorder class is used for the recording of media content. More...
| Header: | #include <QMediaRecorder> |
| qmake: | QT += multimedia |
| Inherits: | QObject and QMediaBindableInterface |
| Inherited By: |
| enum | Error { NoError, ResourceError, FormatError, OutOfSpaceError } |
| enum | State { StoppedState, RecordingState, PausedState } |
| enum | Status { UnavailableStatus, UnloadedStatus, LoadingStatus, LoadedStatus, StartingStatus, …, FinalizingStatus } |
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| QMediaRecorder(QMediaObject *mediaObject, QObject *parent = nullptr) | |
| virtual | ~QMediaRecorder() |
| QUrl | actualLocation() const |
| QString | audioCodecDescription(const QString &codec) const |
| QAudioEncoderSettings | audioSettings() const |
| QMultimedia::AvailabilityStatus | availability() const |
| QStringList | availableMetaData() const |
| QString | containerDescription(const QString &format) const |
| QString | containerFormat() const |
| qint64 | duration() const |
| QMediaRecorder::Error | error() const |
| QString | errorString() const |
| bool | isAvailable() const |
| bool | isMetaDataAvailable() const |
| bool | isMetaDataWritable() const |
| bool | isMuted() const |
| QVariant | metaData(const QString &key) const |
| QUrl | outputLocation() const |
| void | setAudioSettings(const QAudioEncoderSettings &settings) |
| void | setContainerFormat(const QString &container) |
| void | setEncodingSettings(const QAudioEncoderSettings &audio, const QVideoEncoderSettings &video = QVideoEncoderSettings(), const QString &container = QString()) |
| void | setMetaData(const QString &key, const QVariant &value) |
| bool | setOutputLocation(const QUrl &location) |
| void | setVideoSettings(const QVideoEncoderSettings &settings) |
| QMediaRecorder::State | state() const |
| QMediaRecorder::Status | status() const |
| QStringList | supportedAudioCodecs() const |
| QList<int> | supportedAudioSampleRates(const QAudioEncoderSettings &settings = QAudioEncoderSettings(), bool *continuous = nullptr) const |
| QStringList | supportedContainers() const |
| QList<qreal> | supportedFrameRates(const QVideoEncoderSettings &settings = QVideoEncoderSettings(), bool *continuous = nullptr) const |
| QList<QSize> | supportedResolutions(const QVideoEncoderSettings &settings = QVideoEncoderSettings(), bool *continuous = nullptr) const |
| QStringList | supportedVideoCodecs() const |
| QString | videoCodecDescription(const QString &codec) const |
| QVideoEncoderSettings | videoSettings() const |
| qreal | volume() const |
| virtual QMediaObject * | mediaObject() const override |
| void | pause() |
| void | record() |
| void | setMuted(bool muted) |
| void | setVolume(qreal volume) |
| void | stop() |
| void | actualLocationChanged(const QUrl &location) |
| void | availabilityChanged(QMultimedia::AvailabilityStatus availability) |
| void | availabilityChanged(bool available) |
| void | durationChanged(qint64 duration) |
| void | error(QMediaRecorder::Error error) |
| void | metaDataAvailableChanged(bool available) |
| void | metaDataChanged(const QString &key, const QVariant &value) |
| void | metaDataChanged() |
| void | metaDataWritableChanged(bool writable) |
| void | mutedChanged(bool muted) |
| void | stateChanged(QMediaRecorder::State state) |
| void | statusChanged(QMediaRecorder::Status status) |
| void | volumeChanged(qreal volume) |
The QMediaRecorder class is a high level media recording class. It's not intended to be used alone but for accessing the media recording functions of other media objects, like QRadioTuner, or QCamera.
recorder = new QMediaRecorder(camera);
QAudioEncoderSettings audioSettings;
audioSettings.setCodec("audio/amr");
audioSettings.setQuality(QMultimedia::HighQuality);
recorder->setAudioSettings(audioSettings);
recorder->setOutputLocation(QUrl::fromLocalFile(fileName));
recorder->record(); See also QAudioRecorder.
| Constant | Value | Description |
|---|---|---|
QMediaRecorder::NoError |
0 |
No Errors. |
QMediaRecorder::ResourceError |
1 |
Device is not ready or not available. |
QMediaRecorder::FormatError |
2 |
Current format is not supported. |
QMediaRecorder::OutOfSpaceError |
3 |
No space left on device. |
| Constant | Value | Description |
|---|---|---|
QMediaRecorder::StoppedState |
0 |
The recorder is not active. If this is the state after recording then the actual created recording has finished being written to the final location and is ready on all platforms except on Android. On Android, due to platform limitations, there is no way to be certain that the recording has finished writing to the final location. |
QMediaRecorder::RecordingState |
1 |
The recording is requested. |
QMediaRecorder::PausedState |
2 |
The recorder is paused. |
| Constant | Value | Description |
|---|---|---|
QMediaRecorder::UnavailableStatus |
0 |
The recorder is not available or not supported by connected media object. |
QMediaRecorder::UnloadedStatus |
1 |
The recorder is avilable but not loaded. |
QMediaRecorder::LoadingStatus |
2 |
The recorder is initializing. |
QMediaRecorder::LoadedStatus |
3 |
The recorder is initialized and ready to record media. |
QMediaRecorder::StartingStatus |
4 |
Recording is requested but not active yet. |
QMediaRecorder::RecordingStatus |
5 |
Recording is active. |
QMediaRecorder::PausedStatus |
6 |
Recording is paused. |
QMediaRecorder::FinalizingStatus |
7 |
Recording is stopped with media being finalized. |
This property holds the actual location of the last media content.
The actual location is usually available after recording starts, and reset when new location is set or new recording starts.
Access functions:
| QUrl | actualLocation() const |
Notifier signal:
| void | actualLocationChanged(const QUrl &location) |
This property holds the recorded media duration in milliseconds.
Access functions:
| qint64 | duration() const |
Notifier signal:
| void | durationChanged(qint64 duration) |
This property holds whether access to a media object's meta-data is available.
If this is true there is meta-data available, otherwise there is no meta-data available.
Access functions:
| bool | isMetaDataAvailable() const |
Notifier signal:
| void | metaDataAvailableChanged(bool available) |
This property holds whether a media object's meta-data is writable.
If this is true the meta-data is writable, otherwise the meta-data is read-only.
Access functions:
| bool | isMetaDataWritable() const |
Notifier signal:
| void | metaDataWritableChanged(bool writable) |
This property holds whether a recording audio stream is muted.
Access functions:
| bool | isMuted() const |
| void | setMuted(bool muted) |
Notifier signal:
| void | mutedChanged(bool muted) |
This property holds the destination location of media content.
Setting the location can fail, for example when the service supports only local file system locations but a network URL was passed. If the service does not support media recording this setting the output location will always fail.
The location can be relative or empty; in this case the recorder uses the system specific place and file naming scheme. After recording has stated, QMediaRecorder::outputLocation() returns the actual output location.
Access functions:
| QUrl | outputLocation() const |
| bool | setOutputLocation(const QUrl &location) |
This property holds the current state of the media recorder.
The state property represents the user request and is changed synchronously during record(), pause() or stop() calls. Recorder state may also change asynchronously when recording fails.
Access functions:
| QMediaRecorder::State | state() const |
Notifier signal:
| void | stateChanged(QMediaRecorder::State state) |
This property holds the current status of the media recorder.
The status is changed asynchronously and represents the actual status of media recorder.
Access functions:
| QMediaRecorder::Status | status() const |
Notifier signal:
| void | statusChanged(QMediaRecorder::Status status) |
This property holds the current recording audio volume.
The volume is scaled linearly from 0.0 (silence) to 1.0 (full volume). Values outside this range will be clamped.
The default volume is 1.0.
UI volume controls should usually be scaled nonlinearly. For example, using a logarithmic scale will produce linear changes in perceived loudness, which is what a user would normally expect from a volume control. See QAudio::convertVolume() for more details.
Access functions:
| qreal | volume() const |
| void | setVolume(qreal volume) |
Notifier signal:
| void | volumeChanged(qreal volume) |
Constructs a media recorder which records the media produced by mediaObject.
The parent is passed to QMediaObject.
[signal] void QMediaRecorder::actualLocationChanged(const QUrl &location)
Signals that the actual location of the recorded media has changed. This signal is usually emitted when recording starts.
Note: Notifier signal for property actualLocation.
[signal] void QMediaRecorder::availabilityChanged(QMultimedia::AvailabilityStatus availability)
Signals that the service availability has changed to availability.
Note: Signal availabilityChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(mediaRecorder, QOverload<QMultimedia::AvailabilityStatus>::of(&QMediaRecorder::availabilityChanged),
[=](QMultimedia::AvailabilityStatus availability){ /* ... */ }); [signal] void QMediaRecorder::availabilityChanged(bool available)
Signals that the media recorder is now available (if available is true), or not.
Note: Signal availabilityChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(mediaRecorder, QOverload<bool>::of(&QMediaRecorder::availabilityChanged),
[=](bool available){ /* ... */ }); [signal] void QMediaRecorder::durationChanged(qint64 duration)
Signals that the duration of the recorded media has changed.
Note: Notifier signal for property duration.
[signal] void QMediaRecorder::error(QMediaRecorder::Error error)
Signals that an error has occurred.
Note: Signal error is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(mediaRecorder, QOverload<QMediaRecorder::Error>::of(&QMediaRecorder::error),
[=](QMediaRecorder::Error error){ /* ... */ }); [signal] void QMediaRecorder::metaDataAvailableChanged(bool available)
Signals that the available state of a media object's meta-data has changed.
Note: Notifier signal for property metaDataAvailable.
[signal] void QMediaRecorder::metaDataChanged(const QString &key, const QVariant &value)
Signal the changes of one meta-data element value with the given key.
Note: Signal metaDataChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(mediaRecorder, QOverload<const QString &, const QVariant &>::of(&QMediaRecorder::metaDataChanged),
[=](const QString &key, const QVariant &value){ /* ... */ }); [signal] void QMediaRecorder::metaDataChanged()
Signals that a media object's meta-data has changed.
If multiple meta-data elements are changed, metaDataChanged(const QString &key, const QVariant &value) signal is emitted for each of them with metaDataChanged() changed emitted once.
Note: Signal metaDataChanged is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(mediaRecorder, QOverload<>::of(&QMediaRecorder::metaDataChanged),
[=](){ /* ... */ }); [signal] void QMediaRecorder::metaDataWritableChanged(bool writable)
Signals that the writable state of a media object's meta-data has changed.
Note: Notifier signal for property metaDataWritable.
[signal] void QMediaRecorder::mutedChanged(bool muted)
Signals that the muted state has changed. If true the recording is being muted.
Note: Notifier signal for property muted.
[slot] void QMediaRecorder::pause()
Pause recording.
The recorder state is changed to QMediaRecorder::PausedState.
Depending on platform recording pause may be not supported, in this case the recorder state stays unchanged.
[slot] void QMediaRecorder::record()
Start recording.
While the recorder state is changed immediately to QMediaRecorder::RecordingState, recording may start asynchronously, with statusChanged(QMediaRecorder::RecordingStatus) signal emitted when recording starts.
If recording fails error() signal is emitted with recorder state being reset back to QMediaRecorder::StoppedState.
[signal] void QMediaRecorder::stateChanged(QMediaRecorder::State state)
Signals that a media recorder's state has changed.
Note: Notifier signal for property state.
[slot] void QMediaRecorder::stop()
Stop recording.
The recorder state is changed to QMediaRecorder::StoppedState.
[virtual] QMediaRecorder::~QMediaRecorder()
Destroys a media recorder object.
Returns a description of an audio codec.
Returns the audio encoder settings being used.
See also setAudioSettings() and setEncodingSettings().
Returns the availability of this functionality.
See also availabilityChanged().
Returns a list of keys there is meta-data available for.
Returns a description of a container format.
Returns the selected container format.
See also setContainerFormat().
Returns the current error state.
See also errorString().
Returns a string describing the current error state.
See also error().
Returns true if media recorder service ready to use.
See also availabilityChanged().
[override virtual] QMediaObject *QMediaRecorder::mediaObject() const
Reimplements: QMediaBindableInterface::mediaObject() const.
Returns the QMediaObject instance that this QMediaRecorder is bound too, or 0 otherwise.
Returns the value associated with a meta-data key.
See also setMetaData().
Sets the audio encoder settings.
If some parameters are not specified, or null settings are passed, the encoder will choose default encoding parameters, depending on media source properties.
It's only possible to change settings when the encoder is in the QMediaEncoder::StoppedState state.
See also audioSettings(), videoSettings(), and containerFormat().
Sets the media container format.
If the container format is not specified, the encoder will choose format, depending on media source properties and encoding settings selected.
It's only possible to change settings when the encoder is in the QMediaEncoder::StoppedState state.
See also audioSettings(), videoSettings(), and containerFormat().
Sets the audio and video encoder settings and container format.
If some parameters are not specified, or null settings are passed, the encoder will choose default encoding parameters, depending on media source properties.
It's only possible to change settings when the encoder is in the QMediaEncoder::StoppedState state.
See also audioSettings(), videoSettings(), and containerFormat().
Sets a value for a meta-data key.
Note: To ensure that meta data is set corretly, it should be set before starting the recording. Once the recording is stopped, any meta data set will be attached to the next recording.
See also metaData().
Sets the video encoder settings.
If some parameters are not specified, or null settings are passed, the encoder will choose default encoding parameters, depending on media source properties.
It's only possible to change settings when the encoder is in the QMediaEncoder::StoppedState state.
See also audioSettings(), videoSettings(), and containerFormat().
Returns the current media recorder state.
Note: Getter function for property state.
See also QMediaRecorder::State.
Returns the current media recorder status.
Note: Getter function for property status.
See also QMediaRecorder::Status.
Returns a list of supported audio codecs.
Returns a list of supported audio sample rates.
If non null audio settings parameter is passed, the returned list is reduced to sample rates supported with partial settings applied.
This can be used to query the list of sample rates, supported by specific audio codec.
If the encoder supports arbitrary sample rates within the supported rates range, *continuous is set to true, otherwise *continuous is set to false.
Returns a list of supported container formats.
Returns a list of frame rates video can be encoded at.
If non null video settings parameter is passed, the returned list is reduced to frame rates supported with partial settings like video codec or resolution applied.
If the encoder supports arbitrary frame rates within the supported range, *continuous is set to true, otherwise *continuous is set to false.
See also QVideoEncoderSettings::frameRate().
Returns a list of resolutions video can be encoded at.
If non null video settings parameter is passed, the returned list is reduced to resolution supported with partial settings like video codec or framerate applied.
If the encoder supports arbitrary resolutions within the supported range, *continuous is set to true, otherwise *continuous is set to false.
See also QVideoEncoderSettings::resolution().
Returns a list of supported video codecs.
Returns a description of a video codec.
See also setEncodingSettings().
Returns the video encoder settings being used.
See also setVideoSettings() and setEncodingSettings().
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Licensed under the GNU Free Documentation License, Version 1.3.
https://doc.qt.io/qt-5.15/qmediarecorder.html