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QMediaRecorder 类

QMediaRecorder 类用于编码和录制捕获会话。 更多...

头： #include <QMediaRecorder>
CMake: find_package(Qt6 REQUIRED COMPONENTS Multimedia)
target_link_libraries(mytarget PRIVATE Qt6::Multimedia)
qmake: QT += multimedia
实例化： MediaRecorder
继承： QObject

公共类型

enum EncodingMode { ConstantQualityEncoding, ConstantBitRateEncoding, AverageBitRateEncoding, TwoPassEncoding }
enum Error { NoError, ResourceError, FormatError, OutOfSpaceError, LocationNotWritable }
enum Quality { VeryLowQuality, LowQuality, NormalQuality, HighQuality, VeryHighQuality }
enum RecorderState { StoppedState, RecordingState, PausedState }

特性

公共函数

QMediaRecorder (QObject * parent = nullptr)
virtual ~QMediaRecorder ()
QUrl actualLocation () const
void addMetaData (const QMediaMetaData & metaData )
int audioBitRate () const
int audioChannelCount () const
int audioSampleRate () const
QMediaCaptureSession * captureSession () const
qint64 duration () const
QMediaRecorder::EncodingMode encodingMode () const
QMediaRecorder::Error error () const
QString errorString () const
bool isAvailable () const
QMediaFormat mediaFormat () const
QMediaMetaData metaData () const
QUrl outputLocation () const
QMediaRecorder::Quality quality () const
QMediaRecorder::RecorderState recorderState () const
void setAudioBitRate (int bitRate )
void setAudioChannelCount (int channels )
void setAudioSampleRate (int sampleRate )
void setEncodingMode (QMediaRecorder::EncodingMode mode )
void setMediaFormat (const QMediaFormat & format )
void setMetaData (const QMediaMetaData & metaData )
void setOutputLocation (const QUrl & location )
void setQuality (QMediaRecorder::Quality quality )
void setVideoBitRate (int bitRate )
void setVideoFrameRate (qreal frameRate )
void setVideoResolution (const QSize & size )
void setVideoResolution (int width , int height )
int videoBitRate () const
qreal videoFrameRate () const
QSize videoResolution () const

公共槽

void pause ()
void record ()
void stop ()

信号

void actualLocationChanged (const QUrl & location )
void audioBitRateChanged ()
void audioChannelCountChanged ()
void audioSampleRateChanged ()
void durationChanged (qint64 duration )
void encoderSettingsChanged ()
void encodingModeChanged ()
void errorChanged ()
void errorOccurred (QMediaRecorder::Error error , const QString & errorString )
void mediaFormatChanged ()
void metaDataChanged ()
void qualityChanged ()
void recorderStateChanged (QMediaRecorder::RecorderState state )
void videoBitRateChanged ()
void videoFrameRateChanged ()
void videoResolutionChanged ()

详细描述

QMediaRecorder 类编码和录制的媒体生成于 QMediaCaptureSession . 

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

成员类型文档编制

enum QMediaRecorder:: EncodingMode

枚举编码模式。

常量 值 描述
QMediaRecorder::ConstantQualityEncoding 0 Encoding will aim to have a constant quality, adjusting bitrate to fit.
QMediaRecorder::ConstantBitRateEncoding 1 Encoding will use a constant bit rate, adjust quality to fit.
QMediaRecorder::AverageBitRateEncoding 2 Encoding will try to keep an average bitrate setting, but will use more or less as needed.
QMediaRecorder::TwoPassEncoding 3 The media will first be processed to determine the characteristics, and then processed a second time allocating more bits to the areas that need it.

enum QMediaRecorder:: Error

常量 值 描述
QMediaRecorder::NoError 0 没有错误。
QMediaRecorder::ResourceError 1 设备未就绪 (或不可用)。
QMediaRecorder::FormatError 2 不支持当前格式。
QMediaRecorder::OutOfSpaceError 3 设备没有剩余空间。
QMediaRecorder::LocationNotWritable 4 输出位置不可写。

enum QMediaRecorder:: Quality

枚举品质编码级别。

常量 值
QMediaRecorder::VeryLowQuality 0
QMediaRecorder::LowQuality 1
QMediaRecorder::NormalQuality 2
QMediaRecorder::HighQuality 3
QMediaRecorder::VeryHighQuality 4

enum QMediaRecorder:: RecorderState

常量 值 描述
QMediaRecorder::StoppedState 0 录制器不活动。
QMediaRecorder::RecordingState 1 请求录制。
QMediaRecorder::PausedState 2 录制器暂停。

特性文档编制

[read-only] actualLocation : const QUrl

此特性保持最后媒体内容的实际位置。

The actual location is usually available after recording starts, and reset when new location is set or new recording starts.

访问函数：

QUrl actualLocation () const

通知程序信号：

void actualLocationChanged (const QUrl & location )

[read-only] duration : const qint64

此特性保持录制媒体的持续时间 (以毫秒为单位)。

访问函数：

qint64 duration () const

通知程序信号：

void durationChanged (qint64 duration )

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

返回当前错误状态。

访问函数：

QMediaRecorder::Error error () const

通知程序信号：

void errorChanged ()

另请参阅 errorString ().

[read-only] errorString : const QString

返回描述当前错误状态的字符串。

访问函数：

QString errorString () const

通知程序信号：

void errorChanged ()

另请参阅 error ().

mediaFormat : QMediaFormat

返回录制媒体格式。

访问函数：

QMediaFormat mediaFormat () const
void setMediaFormat (const QMediaFormat & format )

通知程序信号：

void mediaFormatChanged ()

metaData : QMediaMetaData

返回录制关联的 metaData。

访问函数：

QMediaMetaData metaData () const
void setMetaData (const QMediaMetaData & metaData )

通知程序信号：

void metaDataChanged ()

outputLocation : QUrl

此特性保持媒体内容的目的地位置。

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 an errorOccured() signal is emitted.

The output location can be relative or empty; in the latter case the recorder uses the system specific place and file naming scheme.

访问函数：

QUrl outputLocation () const
void setOutputLocation (const QUrl & location )

quality : Quality

返回录制品质。

访问函数：

QMediaRecorder::Quality quality () const
void setQuality (QMediaRecorder::Quality quality )

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

此特性保持媒体录制器的当前状态。

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.

访问函数：

QMediaRecorder::RecorderState recorderState () const

通知程序信号：

void recorderStateChanged (QMediaRecorder::RecorderState state )

成员函数文档编制

QMediaRecorder:: QMediaRecorder ( QObject * parent = nullptr)

Constructs a media recorder which records the media produced by a microphone and camera. The media recorder is a child of parent .

[虚拟] QMediaRecorder:: ~QMediaRecorder ()

销毁媒体录制器对象。

[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： 通知程序信号对于特性 actualLocation .

void QMediaRecorder:: addMetaData (const QMediaMetaData & metaData )

添加 metaData 到录制媒体。

int QMediaRecorder:: audioBitRate () const

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

另请参阅 setAudioBitRate ().

[signal] void QMediaRecorder:: audioBitRateChanged ()

Signals when the recording audio bit rate changes.

int QMediaRecorder:: audioChannelCount () const

Returns the number of audio channels.

另请参阅 setAudioChannelCount ().

[signal] void QMediaRecorder:: audioChannelCountChanged ()

Signals when the recording audio channel count changes.

int QMediaRecorder:: audioSampleRate () const

Returns the audio sample rate in Hz.

另请参阅 setAudioSampleRate ().

[signal] void QMediaRecorder:: audioSampleRateChanged ()

Signals when the recording audio sample rate changes.

QMediaCaptureSession *QMediaRecorder:: captureSession () const

Returns the media capture session.

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

信号 duration of the recorded media has changed.

注意： 通知程序信号对于特性 duration .

[signal] void QMediaRecorder:: encoderSettingsChanged ()

Signals when the encoder settings change.

QMediaRecorder::EncodingMode QMediaRecorder:: encodingMode () const

Returns the encoding mode.

另请参阅 setEncodingMode () 和 EncodingMode .

[signal] void QMediaRecorder:: encodingModeChanged ()

Signals when the encoding mode changes.

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

Signals that an error has occurred, with errorString containing a description of the error.

bool QMediaRecorder:: isAvailable () const

返回 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： 通知程序信号对于特性 metaData .

[slot] void QMediaRecorder:: pause ()

暂停录制。

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.

[slot] void QMediaRecorder:: record ()

开始录制。

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

若录制失败 error () signal is emitted with recorder state being reset back to QMediaRecorder::StoppedState .

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 函数对于特性 recorderState。

另请参阅 QMediaRecorder::RecorderState .

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

Signals that a media recorder's state 已改变。

注意： 通知程序信号对于特性 recorderState .

void QMediaRecorder:: setAudioBitRate ( int bitRate )

设置音频 bitRate 以位每秒为单位。

另请参阅 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.

另请参阅 audioChannelCount ().

void QMediaRecorder:: setAudioSampleRate ( int sampleRate )

设置音频 sampleRate (以 Hz 为单位)。

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.

另请参阅 audioSampleRate ().

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

设置编码 mode 设置。

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

另请参阅 encodingMode () 和 EncodingMode .

void QMediaRecorder:: setMetaData (const QMediaMetaData & metaData )

将元数据设为 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 函数对于特性 metaData .

另请参阅 metaData ().

void QMediaRecorder:: setVideoBitRate ( int bitRate )

设置视频 bitRate 以位每秒为单位。

另请参阅 videoBitRate ().

void QMediaRecorder:: setVideoFrameRate ( qreal frameRate )

设置视频 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.

另请参阅 videoFrameRate ().

void QMediaRecorder:: setVideoResolution (const QSize & size )

Sets the resolution of the encoded video to size .

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

另请参阅 videoResolution ().

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

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

这是重载函数。

[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.

另请参阅 setVideoBitRate ().

[signal] void QMediaRecorder:: videoBitRateChanged ()

Signals when the recording video bit rate changes.

qreal QMediaRecorder:: videoFrameRate () const

返回视频帧速率。

另请参阅 setVideoFrameRate ().

[signal] void QMediaRecorder:: videoFrameRateChanged ()

Signals when the recording video frame rate changes.

QSize QMediaRecorder:: videoResolution () const

Returns the resolution of the encoded video.

另请参阅 setVideoResolution ().

[signal] void QMediaRecorder:: videoResolutionChanged ()

Signals when the video recording resolution changes.

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