AbstractMediaStream Class Reference [Playback]

Base class for custom media data streams. More...

#include <Phonon/AbstractMediaStream>

Inheritance diagram for AbstractMediaStream:

List of all members.

Protected Member Functions
	AbstractMediaStream (QObject *parent=0)
qint64	streamSize () const
void	setStreamSize (qint64)
bool	streamSeekable () const
void	setStreamSeekable (bool)
void	writeData (const QByteArray &data)
void	endOfData ()
void	error (Phonon::ErrorType errorType, const QString &errorString)
virtual void	reset ()=0
virtual void	needData ()=0
virtual void	enoughData ()
virtual void	seekStream (qint64 offset)

---

Detailed Description

Base class for custom media data streams.

Implement this class to provide a custom data stream to the backend. The class supports both, the push and the pull model.

Push:

 PushStream::PushStream(QObject *parent)
   : AbstractMediaStream(parent), m_timer(new QTimer(this))
 {
   setStreamSize(getMediaStreamSize());

   connect(m_timer, SIGNAL(timeout()), SLOT(moreData()));
   m_timer->setInterval(0);
 }

 void PushStream::moreData()
 {
   const QByteArray data = getMediaData();
   if (data.isEmpty()) {
     endOfData();
   } else {
     writeData(data);
   }
 }

 void PushStream::needData()
 {
   m_timer->start();
   moreData();
 }

 void PushStream::enoughData()
 {
   m_timer->stop();
 }

Pull:

 PullStream::PullStream(QObject *parent)
   : AbstractMediaStream(parent)
 {
   setStreamSize(getMediaStreamSize());
 }

 void PullStream::needData()
 {
   const QByteArray data = getMediaData();
   if (data.isEmpty()) {
     endOfData();
   } else {
     writeData(data);
   }
 }

Author:

Matthias Kretz <kretz@kde.org>

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Constructor & Destructor Documentation

AbstractMediaStream

(

QObject *

parent = 0

)

[explicit, protected]

Constructs an AbstractMediaStream object with a parent.

---

Member Function Documentation

void endOfData

(

)

[protected]

Tells the backend that the media data stream is at its end.

Warning:

Don't call this function before the first needData() is emitted.

virtual void enoughData

(

)

[protected, virtual]

Reimplement this function to be notified when the backend has enough data and your stream object may take a break.

This method is important for pushing data to the backend in order to not fill the backend buffer unnecessarily.

void error	(	Phonon::ErrorType	errorType,
		const QString &	errorString
	)			[protected]

If an I/O error occurs you should call this function to make MediaObject go into ErrorState.

See also:

MediaObject::errorType()

MediaObject::errorString()

virtual void needData

(

)

[protected, pure virtual]

Reimplement this function to be notified when the backend needs data.

When this function is called you should try to call writeData or endOfData before returning.

virtual void reset

(

)

[protected, pure virtual]

Reimplement this function to reset the stream.

Subsequent calls to writeData should start from the first position of the data unless a seek is requested.

The function is necessary for the case where a non-seekable MediaStream is played more than once. For a seekable stream the implementation can simply call

 seekStream(0);

.

virtual void seekStream

(

qint64

offset

)

[protected, virtual]

Reimplement this function if your stream is seekable.

When this function is called the next call to writeData has to be at the requested offset.

Warning:

Do not call the parent implementation.

void setStreamSeekable

(

bool

)

[protected]

Sets whether your data stream is seekable.

Defaults to false.

If you set this to true you have to implement the seekStream function.

void setStreamSize

(

qint64

)

[protected]

Sets the size of the stream in number of bytes.

A negative value means that the length of the stream cannot be known.

Defaults to 0.

This function has to be called. A backend will not call needData() until the stream size is set.

bool streamSeekable

(

)

const [protected]

Returns whether your data stream is set as seekable.

Defaults to false.

qint64 streamSize

(

)

const [protected]

Returns the stream size that was set with setStreamSize.

A negative value means that the length of the stream cannot be known.

Defaults to 0.

void writeData

(

const QByteArray &

data

)

[protected]

Sends the media data to the backend for decoding.

Warning:

Don't call this function before the first needData() is emitted.

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The documentation for this class was generated from the following file:

• abstractmediastream.h