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5. QtMultimedia
6. QMediaRecorder

QMediaCaptureSession session;
QAudioInput audioInput;
session.setAudioInput(&input);
QMediaRecorder recorder;
session.setRecorder(&recorder);
recorder.setQuality(QMediaRecorder::HighQuality);
recorder.setOutputLocation(QUrl::fromLocalFile("test.mp3"));
recorder.record();
					

成員類型文檔編製

enum QMediaRecorder:: EncodingMode

枚舉編碼模式。

enum QMediaRecorder:: Error

enum QMediaRecorder:: Quality

枚舉品質編碼級彆。

enum QMediaRecorder:: RecorderState

特性文檔編製

[read-only] actualLocation : const QUrl

此特性保持最後媒體內容的實際位置。

The actual location is reset when a new outputLocation or a non-null outputDevice is assigned. When record () is invoked and outputDevice is null or not writable, the recorder generates the actual location basing on the following rules.

• 若 outputLocation is empty, a directory, or a file without an extension, the recorder generates the appropriate extension based on the selected media format and system MIME types.
• 若 outputLocation is a directory, the recorder generates a new file name within it.
• 若 outputLocation is empty, the recorder generates a new file name in the system-specific directory for audio or video.
• The recorder generates the actual location before emitting recorderStateChanged(RecordingState) .

訪問函數：

通知程序信號：

audioBitRate : int

This property holds the bit rate of the compressed audio stream in bits per second.

訪問函數：

通知程序信號：

audioChannelCount : int

This property holds the number of audio channels.

訪問函數：

通知程序信號：

audioSampleRate : int

This property holds the audio sample rate in Hz.

訪問函數：

通知程序信號：

autoStop : bool

This property controls whether the media recorder stops automatically when all media inputs have reported the end of the stream or have been deactivated.

The end of the stream is reported by sending an empty media frame, which you can send explicitly via QVideoFrameInput or QAudioBufferInput .

Video inputs, specificly, QCamera , QScreenCapture and QWindowCapture , can be deactivated via the function setActive .

默認為 false .

QMediaRecorder::autoStop is only supported with the FFmpeg backend.

訪問函數：

通知程序信號：

另請參閱 QCamera , QScreenCapture ，和 QWindowCapture .

[read-only] duration : const qint64

此特性保持錄製媒體的持續時間 (以毫秒為單位)。

訪問函數：

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encodingMode : QMediaRecorder::EncodingMode

This property holds the encoding mode.

訪問函數：

通知程序信號：

另請參閱 EncodingMode .

[read-only] error : const QMediaRecorder::Error

返迴當前錯誤狀態。

訪問函數：

通知程序信號：

另請參閱 errorString ().

[read-only] errorString : const QString

返迴描述當前錯誤狀態的字符串。

訪問函數：

通知程序信號：

另請參閱 error ().

mediaFormat : QMediaFormat

This property holds the current QMediaFormat of the recorder.

The value of this property may change when invoking record (). If this happens, the mediaFormatChanged() signal will be emitted. This will always happen if the QMediaFormat::audioCodec or QMediaFormat::fileFormat properties are set to unspecified. If a video source ( QCamera , QScreenCapture ，或 QVideoFrameInput ) is connected to the QMediaCaptureSession , QMediaFormat::videoCodec must also be specified. The QMediaFormat::audioCodec and QMediaFormat::videoCodec property values may also change if the media backend does not support the selected file format or codec.

The QMediaFormat::fileFormat property value may also change to an audio only format if a video format was requested, but QMediaCaptureSession does not have a video source connected. For example, if QMediaFormat::fileFormat 被設為 QMediaFormat::MPEG4 , it may be changed to QMediaFormat::Mpeg4Audio .

Applications can determine if mediaFormat will change before recording starts by calling the QMediaFormat::isSupported () function. When recording without any video inputs, record () will not be changed the QMediaFormat if the following is true:

• QMediaFormat::fileFormat is specified
• QMediaFormat::audioCodec is specified
• QMediaFormat::videoCodec is unspecified
• QMediaFormat::isSupported () 返迴 true

When recording with video input, mediaFormat will not be changed if the following is true:

• QMediaFormat::fileFormat is specified
• QMediaFormat::audioCodec is specified
• QMediaFormat::videoCodec is specified
• QMediaFormat::isSupported () 返迴 true

注意： The QMediaRecorder does not take the file name extension from the outputLocation property into account when determining the QMediaFormat::fileFormat , and will not adjust the extension of the outputLocation QUrl to match the selected file format if an extension is specified. Applications should therefore make sure to set the QMediaRecorder::mediaFormat::fileFormat to match the file extension, or not specify a file extension. If no file extension is specified, the actualLocation file extension will be updated to match the file format used for recording.

訪問函數：

通知程序信號：

另請參閱 QMediaFormat::isSupported () 和 actualLocation .

metaData : QMediaMetaData

返迴錄製關聯的 metaData。

訪問函數：

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outputLocation : QUrl

此特性保持媒體內容的目的地位置。

Setting the location can fail, for example when the service supports only local file system locations but a network URL was passed. If the operation fails, the errorOccurred () 信號發射。

The output location is ignored if a writable outputDevice has been assigned to the recorder. This behavior may change in the future, so we recommend setting only one output, either outputLocation or outputDevice .

The output location can be empty, a directory, or a file. The path to a directory or file can be relative or absolute. The record () method generates the actual location according to the specified output location and system-specific settings. Refer to the actualLocation property description for details.

訪問函數：

另請參閱 actualLocation and outputDevice ().

quality : Quality

返迴錄製品質。

訪問函數：

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[read-only] recorderState : const QMediaRecorder::RecorderState

此特性保持媒體錄製器的當前狀態。

The state property represents the user request and is changed synchronously during record (), pause () 或 stop () calls. Recorder state may also change asynchronously when recording fails.

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成員函數文檔編製

QMediaRecorder:: QMediaRecorder ( QObject * parent = nullptr)

Constructs a media recorder. The media recorder is a child of parent .

[override virtual noexcept] QMediaRecorder:: ~QMediaRecorder ()

銷毀媒體錄製器對象。

[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.

注意： 通知程序信號對於特性 actualLocation .

void QMediaRecorder:: addMetaData (const QMediaMetaData & metaData )

添加 metaData 到錄製媒體。

int QMediaRecorder:: audioBitRate () const

Returns the bit rate of the compressed audio stream in bits per second.

注意： getter 函數對於特性 audioBitRate。

另請參閱 setAudioBitRate ().

[signal] void QMediaRecorder:: audioBitRateChanged ()

Signals when the recording audio bit rate changes.

注意： 通知程序信號對於特性 audioBitRate .

int QMediaRecorder:: audioChannelCount () const

Returns the number of audio channels.

注意： Getter function for property audioChannelCount.

另請參閱 setAudioChannelCount ().

[signal] void QMediaRecorder:: audioChannelCountChanged ()

Signals when the recording audio channel count changes.

注意： 通知程序信號對於特性 audioChannelCount .

int QMediaRecorder:: audioSampleRate () const

Returns the audio sample rate in Hz.

注意： Getter function for property audioSampleRate.

另請參閱 setAudioSampleRate ().

[signal] void QMediaRecorder:: audioSampleRateChanged ()

Signals when the recording audio sample rate changes.

注意： 通知程序信號對於特性 audioSampleRate .

QMediaCaptureSession *QMediaRecorder:: captureSession () const

Returns the media capture session.

[signal] void QMediaRecorder:: durationChanged ( qint64 duration )

發射信號，當 duration of the recorded media has changed.

注意： 通知程序信號對於特性 duration .

QMediaRecorder::EncodingMode QMediaRecorder:: encodingMode () const

Returns the encoding mode.

注意： Getter function for property encodingMode.

另請參閱 setEncodingMode () 和 EncodingMode .

[signal] void QMediaRecorder:: encodingModeChanged ()

Signals when the encoding mode changes.

注意： 通知程序信號對於特性 encodingMode .

[signal] void QMediaRecorder:: errorOccurred ( QMediaRecorder::Error error , const QString & errorString )

發射信號，當 error has occurred, with errorString containing a description of the error.

bool QMediaRecorder:: isAvailable () const

返迴 true if media recorder service ready to use.

[signal] void QMediaRecorder:: metaDataChanged ()

Signals that a media object's meta-data has changed.

If multiple meta-data elements are changed metaDataChanged() is emitted once.

注意： 通知程序信號對於特性 metaData .

QIODevice *QMediaRecorder:: outputDevice () const

Returns the output IO device for media content.

另請參閱 setOutputDevice ().

[slot] void QMediaRecorder:: pause ()

暫停錄製。

The recorder state is changed to QMediaRecorder::PausedState .

Depending on the platform, pausing recording may be not supported. In this case the recorder state is unchanged.

[signal] void QMediaRecorder:: qualityChanged ()

Signals when the recording quality changes.

注意： 通知程序信號對於特性 quality .

[slot] void QMediaRecorder:: record ()

Starts recording.

While the recorder state is changed immediately to c{ QMediaRecorder::RecordingState }, recording may start asynchronously.

若錄製失敗 error () signal is emitted with recorder state being reset back to QMediaRecorder::StoppedState .

This method updates actualLocation according to its generation rules.

注意： On mobile devices, recording will happen in the orientation the device had when calling record and is locked for the duration of the recording. To avoid artifacts on the user interface, we recommend to keep the user interface locked to the same orientation as long as the recording is ongoing using the contentOrientation property of QWindow and unlock it again once the recording is finished.

QMediaRecorder::RecorderState QMediaRecorder:: recorderState () const

Returns the current media recorder state.

注意： getter 函數對於特性 recorderState。

另請參閱 QMediaRecorder::RecorderState .

[signal] void QMediaRecorder:: recorderStateChanged ( QMediaRecorder::RecorderState state )

Signals that a media recorder's state 已改變。

注意： 通知程序信號對於特性 recorderState .

void QMediaRecorder:: setAudioBitRate ( int bitRate )

設置音頻 bitRate 以位每秒為單位。

注意： setter 函數對於特性 audioBitRate .

另請參閱 audioBitRate ().

void QMediaRecorder:: setAudioChannelCount ( int channels )

Sets the number of audio channels .

A value of -1 indicates the recorder should make an optimal choice based on what is available from the audio source and the limitations of the codec.

注意： setter 函數對於特性 audioChannelCount .

另請參閱 audioChannelCount ().

void QMediaRecorder:: setAudioSampleRate ( int sampleRate )

設置音頻 sampleRate (以 Hz 為單位)。

值 -1 indicates the recorder should make an optimal choice based on what is available from the audio source, and the limitations of the codec.

注意： setter 函數對於特性 audioSampleRate .

另請參閱 audioSampleRate ().

void QMediaRecorder:: setEncodingMode ( QMediaRecorder::EncodingMode mode )

設置編碼 mode 設置。

若 ConstantQualityEncoding is set, the quality encoding parameter is used and bit rates are ignored, otherwise the bitrates are used.

注意： setter 函數對於特性 encodingMode .

另請參閱 encodingMode () 和 EncodingMode .

void QMediaRecorder:: setMetaData (const QMediaMetaData & metaData )

將元數據設為 metaData .

注意： To ensure that meta-data is set correctly, it should be set before starting the recording. Once the recording is started, any meta-data set will be attached to the next recording.

注意： setter 函數對於特性 metaData .

另請參閱 metaData ().

void QMediaRecorder:: setOutputDevice ( QIODevice * device )

Set the output IO device for media content.

The device 必須已打開以 WriteOnly or ReadWrite modes before the recording starts.

The media recorder doesn't take ownership of the specified device . If the recording has been started, the device must be kept alive and open until the signal recorderStateChanged(StoppedState) is emitted.

This method resets actualLocation immediately unless the specified device is null .

If a writable output device is assigned to the recorder, outputLocation is ignored, and actualLocation is not generated when recording starts. This behavior may change in the future, so we recommend setting only one output, either outputLocation or outputDevice .

QMediaRecorder::setOutputDevice is only supported with the FFmpeg backend.

另請參閱 outputDevice () 和 outputLocation .

void QMediaRecorder:: setVideoBitRate ( int bitRate )

設置視頻 bitRate 以位每秒為單位。

注意： setter 函數對於特性 videoBitRate .

另請參閱 videoBitRate ().

void QMediaRecorder:: setVideoFrameRate ( qreal frameRate )

設置視頻 frameRate .

A value of 0 indicates the recorder should make an optimal choice based on what is available from the video source and the limitations of the codec.

注意： setter 函數對於特性 videoFrameRate .

另請參閱 videoFrameRate ().

void QMediaRecorder:: setVideoResolution (const QSize & size )

Sets the resolution of the encoded video to size .

傳遞空 QSize to make the recorder choose an optimal resolution based on what is available from the video source and the limitations of the codec.

注意： setter 函數對於特性 videoResolution .

另請參閱 videoResolution ().

void QMediaRecorder:: setVideoResolution ( int width , int height )

設置 width and height of the resolution of the encoded video.

注意： setter 函數對於特性 videoResolution .

這是重載函數。

[slot] void QMediaRecorder:: stop ()

The recorder will stop the recording. Processing pending video and audio data might however still take some time. The recording is finished, once the state of the media recorder changes to QMediaRecorder::StoppedState .

int QMediaRecorder:: videoBitRate () const

Returns the bit rate of the compressed video stream in bits per second.

注意： getter 函數對於特性 videoBitRate。

另請參閱 setVideoBitRate ().

[signal] void QMediaRecorder:: videoBitRateChanged ()

Signals when the recording video bit rate changes.

注意： 通知程序信號對於特性 videoBitRate .

qreal QMediaRecorder:: videoFrameRate () const

返迴視頻幀速率。

注意： getter 函數對於特性 videoFrameRate。

另請參閱 setVideoFrameRate ().

[signal] void QMediaRecorder:: videoFrameRateChanged ()

Signals when the recording video frame rate changes.

注意： 通知程序信號對於特性 videoFrameRate .

QSize QMediaRecorder:: videoResolution () const

Returns the resolution of the encoded video.

注意： getter 函數對於特性 videoResolution。

另請參閱 setVideoResolution ().

[signal] void QMediaRecorder:: videoResolutionChanged ()

Signals when the video recording resolution changes.

注意： 通知程序信號對於特性 videoResolution .