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QAudioDecoder ClassThe QAudioDecoder class allows decoding audio. More... #include <QAudioDecoder>This class is under development and is subject to change. Inherits: QMediaObject. Public Types
Properties
Public Functions
Public Slots
Signals
Static Public Members
Additional Inherited Members
Detailed DescriptionThe 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. See also QAudioBuffer. Member Type Documentation
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| Constant | Value | Description |
|---|---|---|
| QAudioDecoder::NoError | 0 | No error has occurred. |
| QAudioDecoder::ResourceError | 1 | A media resource couldn't be resolved. |
| QAudioDecoder::FormatError | 2 | The format of a media resource isn't supported. |
| QAudioDecoder::AccessDeniedError | 3 | There are not the appropriate permissions to play a media resource. |
| QAudioDecoder::ServiceMissingError | 4 | A valid playback service was not found, playback cannot proceed. |
enum QAudioDecoder::State
Defines the current state of a media player.
| Constant | Value | Description |
|---|---|---|
| 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. |
Property Documentation
bufferAvailable : const bool
Access functions:
| bool | bufferAvailable() const |
Notifier signal:
| void | bufferAvailableChanged(bool available) |
error : const QString
This property holds a string describing the last error condition.
Access functions:
| QString | errorString() const |
See also error().
sourceFilename : QString
This property holds the active filename being decoded by the decoder object.
Access functions:
| QString | sourceFilename() const |
| void | setSourceFilename(const QString & fileName) |
Notifier signal:
| void | sourceChanged() |
state : const State
This property holds the audio decoder's playback state.
By default this property is QAudioDecoder::Stopped
Access functions:
| State | state() const |
Notifier signal:
| void | stateChanged(QAudioDecoder::State state) |
Member Function Documentation
QAudioDecoder::QAudioDecoder(QObject * parent = 0)
Construct an QAudioDecoder instance parented to parent.
QAudioDecoder::~QAudioDecoder()
Destroys the audio decoder object.
QAudioFormat QAudioDecoder::audioFormat() const
Returns the current audio format of the decoded stream.
Any buffers returned should have this format.
See also setAudioFormat() and formatChanged().
void QAudioDecoder::bufferReady() [signal]
Signals that a new decoded audio buffer is available to be read.
See also read() and bufferAvailable().
qint64 QAudioDecoder::duration() const
Returns total duration (in milliseconds) of the audio stream or -1 if not available.
void QAudioDecoder::durationChanged(qint64 duration) [signal]
Signals that the estimated duration of the decoded data has changed.
See also positionChanged().
Error QAudioDecoder::error() const
Returns the current error state.
void QAudioDecoder::error(QAudioDecoder::Error error) [signal]
Signals that an error condition has occurred.
See also errorString().
void QAudioDecoder::finished() [signal]
Signals that the decoding has finished successfully. If decoding fails, error signal is emitted instead.
See also start(), stop(), and error().
void QAudioDecoder::formatChanged(const QAudioFormat & format) [signal]
Signals that the current audio format of the decoder has changed to format.
See also audioFormat() and setAudioFormat().
QtMultimedia::SupportEstimate QAudioDecoder::hasSupport(const QString & mimeType, const QStringList & codecs = QStringList()) [static]
Returns the level of support an audio decoder has for a mimeType and a set of 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.
void QAudioDecoder::positionChanged(qint64 position) [signal]
Signals that the current position of the decoder has changed.
See also durationChanged().
QAudioBuffer QAudioDecoder::read() const
Read a buffer from the decoder. Returns invalid buffer on failure.
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() will be set to 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.
See also audioFormat().
void QAudioDecoder::setSourceDevice(QIODevice * device)
Sets the current audio 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.
See also sourceDevice().
QIODevice * QAudioDecoder::sourceDevice() const
Returns the current source QIODevice, if one was set. If setSourceFilename() was called, this will be 0.
See also setSourceDevice().
void QAudioDecoder::start() [slot]
Starts decoding the audio resource.
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.
Alternatively, if you wish to block until enough data has been decoded, you can call read() at any time to block until a buffer is ready.
See also read().
void QAudioDecoder::stop() [slot]
Stop decoding audio. Calling start() again will resume decoding from the beginning.