內容

公共類型
特性
公共函數
公共槽
信號
靜態公共成員
詳細描述

QAudioDecoder 類

The QAudioDecoder class allows decoding audio. 更多...

頭：	#include <QAudioDecoder>
qmake:	QT += multimedia
繼承：	QMediaObject

該類在開發且可能改變。

所有成員列錶，包括繼承成員

公共類型

enum	Error { NoError, ResourceError, FormatError, AccessDeniedError, ServiceMissingError }
enum	State { StoppedState, DecodingState }

特性

bufferAvailable : const bool
error : const QString
sourceFilename : QString
state : const State

1 特性繼承自 QMediaObject
1 特性繼承自 QObject

公共函數

	QAudioDecoder (QObject * parent = Q_NULLPTR)
	~QAudioDecoder ()
QAudioFormat	audioFormat () const
bool	bufferAvailable () const
qint64	duration () const
Error	error () const
QString	errorString () const
qint64	position () const
QAudioBuffer	read () const
void	setAudioFormat (const QAudioFormat & format )
void	setSourceDevice (QIODevice * device )
void	setSourceFilename (const QString & fileName )
QIODevice *	sourceDevice () const
QString	sourceFilename () const
狀態	state () const

10 公共函數繼承自 QMediaObject
32 公共函數繼承自 QObject

公共槽

void	start ()
void	stop ()

1 公共槽繼承自 QObject

信號

void	bufferAvailableChanged (bool available )
void	bufferReady ()
void	durationChanged (qint64 duration )
void	error (QAudioDecoder::Error error )
void	finished ()
void	formatChanged (const QAudioFormat & format )
void	positionChanged (qint64 position )
void	sourceChanged ()
void	stateChanged (QAudioDecoder::State state )

6 信號繼承自 QMediaObject
2 信號繼承自 QObject

靜態公共成員

QMultimedia::SupportEstimate

hasSupport (const QString & mimeType , const QStringList & codecs = QStringList())

11 靜態公共成員繼承自 QObject

額外繼承成員

2 保護函數繼承自 QMediaObject
9 保護函數繼承自 QObject

詳細描述

The QAudioDecoder class allows decoding audio.

The QAudioDecoder class is a high level class for decoding local audio media files. It is similar to the QMediaPlayer class except that audio is provided back through this API rather than routed directly to audio hardware, and playlists and network and streaming based media is not supported.

另請參閱 QAudioBuffer .

成員類型文檔編製

enum QAudioDecoder:: Error

定義媒體播放器錯誤條件。

常量	值	描述
`QAudioDecoder::NoError`	`0`	沒有齣現錯誤。
`QAudioDecoder::ResourceError`	`1`	無法解析媒體資源。
`QAudioDecoder::FormatError`	`2`	媒體資源格式不支持。
`QAudioDecoder::AccessDeniedError`	`3`	沒有適當權限來播放媒體資源。
`QAudioDecoder::ServiceMissingError`	`4`	找不到有效迴放服務，無法繼續進行播放。開頭

enum QAudioDecoder:: State

定義媒體播放器的當前狀態。

常量	值	描述
`QAudioDecoder::StoppedState`	`0`	The decoder is not decoding. Decoding will start at the start of the media.
`QAudioDecoder::DecodingState`	`1`	The audio player is currently decoding media.

特性文檔編製

bufferAvailable : const bool

This property holds whether there is a decoded audio buffer available

訪問函數：

bool	bufferAvailable () const

通知程序信號：

void	bufferAvailableChanged (bool available )

error : const QString

此特性保持描述最後一個錯誤條件的字符串。

訪問函數：

QString

errorString () const

另請參閱 error ().

sourceFilename : QString

This property holds the active filename being decoded by the decoder object.

訪問函數：

QString	sourceFilename () const
void	setSourceFilename (const QString & fileName )

通知程序信號：

void	sourceChanged ()

state : const State

This property holds the audio decoder's playback state.

By default this property is QAudioDecoder::Stopped

訪問函數：

狀態	state () const

通知程序信號：

void	stateChanged (QAudioDecoder::State state )

另請參閱 start () 和 stop ().

成員函數文檔編製

QAudioDecoder:: QAudioDecoder ( QObject * parent = Q_NULLPTR)

Construct an QAudioDecoder instance parented to parent .

QAudioDecoder:: ~QAudioDecoder ()

銷毀音頻解碼器對象。

QAudioFormat QAudioDecoder:: audioFormat () const

Returns the current audio format of the decoded stream.

Any buffers returned should have this format.

另請參閱 setAudioFormat () 和 formatChanged ().

bool QAudioDecoder:: bufferAvailable () const

Returns true if a buffer is available to be read, and false otherwise. If there is no buffer available, calling the read () function will return an invalid buffer.

注意： getter 函數對於特性 bufferAvailable .

`[signal]` void QAudioDecoder:: bufferAvailableChanged ( bool available )

Signals the availability (if available is true) of a new buffer.

若 available is false, there are no buffers available.

注意： 通知程序信號對於特性 bufferAvailable .

另請參閱 bufferAvailable () 和 bufferReady ().

`[signal]` void QAudioDecoder:: bufferReady ()

Signals that a new decoded audio buffer is available to be read.

另請參閱 read () 和 bufferAvailable ().

qint64 QAudioDecoder:: duration () const

Returns total duration (in milliseconds) of the audio stream or -1 if not available.

`[signal]` void QAudioDecoder:: durationChanged ( qint64 duration )

Signals that the estimated duration of the decoded data has changed.

另請參閱 positionChanged ().

Error QAudioDecoder:: error () const

返迴當前錯誤狀態。

`[signal]` void QAudioDecoder:: error ( QAudioDecoder::Error error )

發射信號，當 error 條件齣現。

注意： 信號 error 在此類中是重載。要使用函數指針句法連接到此信號，必須在靜態鑄造中指定信號類型，如此範例所示：

connect(audioDecoder, static_cast<void(QAudioDecoder::*)(QAudioDecoder::Error)>(&QAudioDecoder::error),
    [=](QAudioDecoder::Error error){ /* ... */ });

另請參閱 errorString ().

`[signal]` void QAudioDecoder:: finished ()

Signals that the decoding has finished successfully. If decoding fails, error signal is emitted instead.

另請參閱 start (), stop ()，和 error ().

`[signal]` void QAudioDecoder:: formatChanged (const QAudioFormat & format )

Signals that the current audio format of the decoder has changed to format .

另請參閱 audioFormat () 和 setAudioFormat ().

`[static]` QMultimedia::SupportEstimate QAudioDecoder:: hasSupport (const QString & mimeType , const QStringList & codecs = QStringList())

Returns the level of support an audio decoder has for a mimeType 和一組 codecs .

qint64 QAudioDecoder:: position () const

Returns position (in milliseconds) of the last buffer read from the decoder or -1 if no buffers have been read.

`[signal]` void QAudioDecoder:: positionChanged ( qint64 position )

Signals that the current position of the decoder has changed.

另請參閱 durationChanged ().

QAudioBuffer QAudioDecoder:: read () const

Read a buffer from the decoder, if one is available. Returns an invalid buffer if there are no decoded buffers currently available, or on failure. In both cases this function will not block.

You should either respond to the bufferReady () signal or check the bufferAvailable () function before calling read() to make sure you get useful data.

void QAudioDecoder:: setAudioFormat (const QAudioFormat & format )

Set the desired audio format for decoded samples to format .

This property can only be set while the decoder is stopped. Setting this property at other times will be ignored.

If the decoder does not support this format, error () 會被設為 FormatError .

If you do not specify a format, the format of the decoded audio itself will be used. Otherwise, some format conversion will be applied.

If you wish to reset the decoded format to that of the original audio file, you can specify an invalid format .

另請參閱 audioFormat ().

void QAudioDecoder:: setSourceDevice ( QIODevice * device )

設置當前音頻 QIODevice to device .

When this property is set any current decoding is stopped, and any audio buffers are discarded.

You can only specify either a source filename or a source QIODevice . Setting one will unset the other.

另請參閱 sourceDevice ().

void QAudioDecoder:: setSourceFilename (const QString & fileName )

Sets the current audio file name to fileName .

When this property is set any current decoding is stopped, and any audio buffers are discarded.

You can only specify either a source filename or a source QIODevice . Setting one will unset the other.

注意： setter 函數對於特性 sourceFilename .

另請參閱 sourceFilename ().

`[signal]` void QAudioDecoder:: sourceChanged ()

Signals that the current source of the decoder has changed.

注意： 通知程序信號對於特性 sourceFilename .

另請參閱 sourceFilename () 和 sourceDevice ().

QIODevice *QAudioDecoder:: sourceDevice () const

返迴當前源 QIODevice , if one was set. If setSourceFilename () was called, this will be 0.

另請參閱 setSourceDevice ().

QString QAudioDecoder:: sourceFilename () const

Returns the current file name to decode. If setSourceDevice was called, this will be empty.

注意： getter 函數對於特性 sourceFilename .

另請參閱 setSourceFilename ().

`[slot]` void QAudioDecoder:: start ()

開始解碼音頻資源。

As data gets decoded, the bufferReady () signal will be emitted when enough data has been decoded. Calling read () will then return an audio buffer without blocking.

若調用 read () before a buffer is ready, an invalid buffer will be returned, again without blocking.

另請參閱 read ().

`[signal]` void QAudioDecoder:: stateChanged ( QAudioDecoder::State state )

發射信號，當 state of the decoder object has changed.

注意： 通知程序信號對於特性 state .

`[slot]` void QAudioDecoder:: stop ()

停止解碼音頻。調用 start () again will resume decoding from the beginning.

內容

QAudioDecoder 類

公共類型

特性

公共函數

公共槽

信號

靜態公共成員

額外繼承成員

詳細描述

成員類型文檔編製

enum QAudioDecoder:: Error

enum QAudioDecoder:: State

特性文檔編製

bufferAvailable : const bool

error : const QString

sourceFilename : QString

state : const State

成員函數文檔編製

QAudioDecoder:: QAudioDecoder ( QObject * parent = Q_NULLPTR)

QAudioDecoder:: ~QAudioDecoder ()

QAudioFormat QAudioDecoder:: audioFormat () const

bool QAudioDecoder:: bufferAvailable () const

[signal] void QAudioDecoder:: bufferAvailableChanged ( bool available )

[signal] void QAudioDecoder:: bufferReady ()

qint64 QAudioDecoder:: duration () const

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

Error QAudioDecoder:: error () const

[signal] void QAudioDecoder:: error ( QAudioDecoder::Error error )

[signal] void QAudioDecoder:: finished ()

[signal] void QAudioDecoder:: formatChanged (const QAudioFormat & format )

[static] QMultimedia::SupportEstimate QAudioDecoder:: hasSupport (const QString & mimeType , const QStringList & codecs = QStringList())

qint64 QAudioDecoder:: position () const

[signal] void QAudioDecoder:: positionChanged ( qint64 position )

QAudioBuffer QAudioDecoder:: read () const

void QAudioDecoder:: setAudioFormat (const QAudioFormat & format )

void QAudioDecoder:: setSourceDevice ( QIODevice * device )

void QAudioDecoder:: setSourceFilename (const QString & fileName )

[signal] void QAudioDecoder:: sourceChanged ()

QIODevice *QAudioDecoder:: sourceDevice () const

QString QAudioDecoder:: sourceFilename () const

[slot] void QAudioDecoder:: start ()

[signal] void QAudioDecoder:: stateChanged ( QAudioDecoder::State state )

[slot] void QAudioDecoder:: stop ()

`[signal]` void QAudioDecoder:: bufferAvailableChanged ( bool available )

`[signal]` void QAudioDecoder:: bufferReady ()

`[signal]` void QAudioDecoder:: durationChanged ( qint64 duration )

`[signal]` void QAudioDecoder:: error ( QAudioDecoder::Error error )

`[signal]` void QAudioDecoder:: finished ()

`[signal]` void QAudioDecoder:: formatChanged (const QAudioFormat & format )

`[static]` QMultimedia::SupportEstimate QAudioDecoder:: hasSupport (const QString & mimeType , const QStringList & codecs = QStringList())

`[signal]` void QAudioDecoder:: positionChanged ( qint64 position )

`[signal]` void QAudioDecoder:: sourceChanged ()

`[slot]` void QAudioDecoder:: start ()

`[signal]` void QAudioDecoder:: stateChanged ( QAudioDecoder::State state )

`[slot]` void QAudioDecoder:: stop ()