Phonon::AbstractMediaStream Class Reference

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

#include <phonon/AbstractMediaStream>

Inheritance diagram for Phonon::AbstractMediaStream:

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 Q_INVOKABLE void	reset ()=0
virtual Q_INVOKABLE void	needData ()=0
virtual Q_INVOKABLE void	enoughData ()
virtual Q_INVOKABLE void	seekStream (qint64 offset)
	AbstractMediaStream (AbstractMediaStreamPrivate &dd, QObject *parent)

Protected Attributes
QScopedPointer < AbstractMediaStreamPrivate >	d_ptr

Friends
class	MediaObject
class	MediaObjectPrivate
class	StreamInterface

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.nosp@m.@kde.nosp@m..org

Constructor & Destructor Documentation

Phonon::AbstractMediaStream::AbstractMediaStream ( QObject *  parent = 0)

explicitprotected

Constructs an AbstractMediaStream object with a parent.

Member Function Documentation

void Phonon::AbstractMediaStream::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.

void Phonon::AbstractMediaStream::enoughData ( )

protectedvirtual

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 Phonon::AbstractMediaStream::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 Q_INVOKABLE void Phonon::AbstractMediaStream::needData ( )

protectedpure 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 Q_INVOKABLE void Phonon::AbstractMediaStream::reset ( )

protectedpure 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);

.

void Phonon::AbstractMediaStream::seekStream ( qint64  offset)

protectedvirtual

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 Phonon::AbstractMediaStream::setStreamSeekable ( bool  s)

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 Phonon::AbstractMediaStream::setStreamSize ( qint64  newSize)

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 Phonon::AbstractMediaStream::streamSeekable ( ) const

protected

Returns whether your data stream is set as seekable.

Defaults to false.

qint64 Phonon::AbstractMediaStream::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 Phonon::AbstractMediaStream::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.

---

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

• /home/me/src/git/p/phonon/phonon/abstractmediastream.h
• /home/me/src/git/p/phonon/phonon/abstractmediastream.cpp