QMediaPlayer Class

The QMediaPlayer class allows the playing of a media source. More...

Header:	#include <QMediaPlayer>
qmake:	QT += multimedia
Inherits:	QMediaObject

• List of all members, including inherited members
• Obsolete members

Public Types

enum	Error { NoError, ResourceError, FormatError, NetworkError, AccessDeniedError, ServiceMissingError }
enum	Flag { LowLatency, StreamPlayback, VideoSurface }
flags	Flags
enum	MediaStatus { UnknownMediaStatus, NoMedia, LoadingMedia, LoadedMedia, StalledMedia, …, InvalidMedia }
enum	State { StoppedState, PlayingState, PausedState }

Properties

audioAvailable : const bool audioRole : QAudio::Role bufferStatus : const int currentMedia : const QMediaContent customAudioRole : QString duration : const qint64 error : const QString media : QMediaContent mediaStatus : const MediaStatus

muted : bool playbackRate : qreal playlist : QMediaPlaylist* position : qint64 seekable : const bool state : const State videoAvailable : const bool volume : int

Public Functions

	QMediaPlayer(QObject *parent = nullptr, QMediaPlayer::Flags flags = Flags())
virtual	~QMediaPlayer()
QAudio::Role	audioRole() const
int	bufferStatus() const
QMediaContent	currentMedia() const
QString	customAudioRole() const
qint64	duration() const
QMediaPlayer::Error	error() const
QString	errorString() const
bool	isAudioAvailable() const
bool	isMuted() const
bool	isSeekable() const
bool	isVideoAvailable() const
QMediaContent	media() const
QMediaPlayer::MediaStatus	mediaStatus() const
const QIODevice *	mediaStream() const
qreal	playbackRate() const
QMediaPlaylist *	playlist() const
qint64	position() const
void	setAudioRole(QAudio::Role audioRole)
void	setCustomAudioRole(const QString &audioRole)
void	setVideoOutput(QVideoWidget *output)
void	setVideoOutput(QGraphicsVideoItem *output)
void	setVideoOutput(QAbstractVideoSurface *surface)
void	setVideoOutput(const QVector<QAbstractVideoSurface *> &surfaces)
QMediaPlayer::State	state() const
QList<QAudio::Role>	supportedAudioRoles() const
QStringList	supportedCustomAudioRoles() const
int	volume() const

Reimplemented Public Functions

virtual QMultimedia::AvailabilityStatus

availability() const override

Public Slots

void	pause()
void	play()
void	setMedia(const QMediaContent &media, QIODevice *stream = nullptr)
void	setMuted(bool muted)
void	setPlaybackRate(qreal rate)
void	setPlaylist(QMediaPlaylist *playlist)
void	setPosition(qint64 position)
void	setVolume(int volume)
void	stop()

Signals

void	audioAvailableChanged(bool available)
void	audioRoleChanged(QAudio::Role role)
void	bufferStatusChanged(int percentFilled)
void	currentMediaChanged(const QMediaContent &media)
void	customAudioRoleChanged(const QString &role)
void	durationChanged(qint64 duration)
void	error(QMediaPlayer::Error error)
void	mediaChanged(const QMediaContent &media)
void	mediaStatusChanged(QMediaPlayer::MediaStatus status)
void	mutedChanged(bool muted)
void	playbackRateChanged(qreal rate)
void	positionChanged(qint64 position)
void	seekableChanged(bool seekable)
void	stateChanged(QMediaPlayer::State state)
void	videoAvailableChanged(bool videoAvailable)
void	volumeChanged(int volume)

Static Public Members

QMultimedia::SupportEstimate

hasSupport(const QString &mimeType, const QStringList &codecs = QStringList(), QMediaPlayer::Flags flags = Flags())

Detailed Description

The QMediaPlayer class is a high level media playback class. It can be used to playback such content as songs, movies and internet radio. The content to playback is specified as a QMediaContent object, which can be thought of as a main or canonical URL with additional information attached. When provided with a QMediaContent playback may be able to commence.

player = new QMediaPlayer;
connect(player, SIGNAL(positionChanged(qint64)), this, SLOT(positionChanged(qint64)));
player->setMedia(QUrl::fromLocalFile("/Users/me/Music/coolsong.mp3"));
player->setVolume(50);
player->play();

QVideoWidget can be used with QMediaPlayer for video rendering and QMediaPlaylist for accessing playlist functionality.

playlist = new QMediaPlaylist;
playlist->addMedia(QUrl("http://example.com/movie1.mp4"));
playlist->addMedia(QUrl("http://example.com/movie2.mp4"));
playlist->addMedia(QUrl("http://example.com/movie3.mp4"));
playlist->setCurrentIndex(1);

player = new QMediaPlayer;
player->setPlaylist(playlist);

videoWidget = new QVideoWidget;
player->setVideoOutput(videoWidget);
videoWidget->show();

player->play();

Since QMediaPlayer is a QMediaObject, you can use several of the QMediaObject functions for things like:

• Accessing the currently playing media's metadata (QMediaObject::metaData() and predefined meta-data keys)
• Checking to see if the media playback service is currently available (QMediaObject::availability())

See also QMediaObject, QMediaService, QVideoWidget, and QMediaPlaylist.

Member Type Documentation

enum QMediaPlayer::Error

Defines a media player error condition.

Constant	Value	Description
QMediaPlayer::NoError	0	No error has occurred.
QMediaPlayer::ResourceError	1	A media resource couldn't be resolved.
QMediaPlayer::FormatError	2	The format of a media resource isn't (fully) supported. Playback may still be possible, but without an audio or video component.
QMediaPlayer::NetworkError	3	A network error occurred.
QMediaPlayer::AccessDeniedError	4	There are not the appropriate permissions to play a media resource.
QMediaPlayer::ServiceMissingError	5	A valid playback service was not found, playback cannot proceed.

enum QMediaPlayer::Flagflags QMediaPlayer::Flags

Constant	Value	Description
QMediaPlayer::LowLatency	0x01	The player is expected to be used with simple audio formats, but playback should start without significant delay. Such playback service can be used for beeps, ringtones, etc.
QMediaPlayer::StreamPlayback	0x02	The player is expected to play QIODevice based streams. If passed to QMediaPlayer constructor, the service supporting streams playback will be chosen.
QMediaPlayer::VideoSurface	0x04	The player is expected to be able to render to a QAbstractVideoSurface output.

The Flags type is a typedef for QFlags<Flag>. It stores an OR combination of Flag values.

enum QMediaPlayer::MediaStatus

Defines the status of a media player's current media.

Constant	Value	Description
QMediaPlayer::UnknownMediaStatus	0	The status of the media cannot be determined.
QMediaPlayer::NoMedia	1	The is no current media. The player is in the StoppedState.
QMediaPlayer::LoadingMedia	2	The current media is being loaded. The player may be in any state.
QMediaPlayer::LoadedMedia	3	The current media has been loaded. The player is in the StoppedState.
QMediaPlayer::StalledMedia	4	Playback of the current media has stalled due to insufficient buffering or some other temporary interruption. The player is in the PlayingState or PausedState.
QMediaPlayer::BufferingMedia	5	The player is buffering data but has enough data buffered for playback to continue for the immediate future. The player is in the PlayingState or PausedState.
QMediaPlayer::BufferedMedia	6	The player has fully buffered the current media. The player is in the PlayingState or PausedState.
QMediaPlayer::EndOfMedia	7	Playback has reached the end of the current media. The player is in the StoppedState.
QMediaPlayer::InvalidMedia	8	The current media cannot be played. The player is in the StoppedState.

enum QMediaPlayer::State

Defines the current state of a media player.

Constant	Value	Description
QMediaPlayer::StoppedState	0	The media player is not playing content, playback will begin from the start of the current track.
QMediaPlayer::PlayingState	1	The media player is currently playing content.
QMediaPlayer::PausedState	2	The media player has paused playback, playback of the current track will resume from the position the player was paused at.

Member Function Documentation

QMediaPlayer::QMediaPlayer(QObject *parent = nullptr, QMediaPlayer::Flags flags = Flags())

Construct a QMediaPlayer instance parented to parent and with flags.

[signal] void QMediaPlayer::audioAvailableChanged(bool available)

Signals the availability of audio content has changed to available.

Note: Notifier signal for property audioAvailable.

[signal] void QMediaPlayer::audioRoleChanged(QAudio::Role role)

Signals that the audio role of the media player has changed.

Note: Notifier signal for property audioRole.

This function was introduced in Qt 5.6.

[signal] void QMediaPlayer::bufferStatusChanged(int percentFilled)

Signal the amount of the local buffer filled as a percentage by percentFilled.

Note: Notifier signal for property bufferStatus.

[signal] void QMediaPlayer::currentMediaChanged(const QMediaContent &media)

Signals that the current playing content has been changed to media.

Note: Notifier signal for property currentMedia.

See also currentMedia() and mediaChanged().

[signal] void QMediaPlayer::customAudioRoleChanged(const QString &role)

Signals that the audio role of the media player has changed.

Note: Notifier signal for property customAudioRole.

This function was introduced in Qt 5.11.

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

Signal the duration of the content has changed to duration, expressed in milliseconds.

Note: Notifier signal for property duration.

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

Signals that an error condition has occurred.

Note: Signal error is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:

connect(mediaPlayer, QOverload<QMediaPlayer::Error>::of(&QMediaPlayer::error),
    [=](QMediaPlayer::Error error){ /* ... */ });

See also errorString().

[signal] void QMediaPlayer::mediaChanged(const QMediaContent &media)

Signals that the media source has been changed to media.

Note: Notifier signal for property media.

See also media() and currentMediaChanged().

[signal] void QMediaPlayer::mediaStatusChanged(QMediaPlayer::MediaStatus status)

Signals that the status of the current media has changed.

Note: Notifier signal for property mediaStatus.

See also mediaStatus().

[signal] void QMediaPlayer::mutedChanged(bool muted)

Signal the mute state has changed to muted.

Note: Notifier signal for property muted.

[slot] void QMediaPlayer::pause()

Pause playing the current source.

[slot] void QMediaPlayer::play()

Start or resume playing the current source.

[signal] void QMediaPlayer::playbackRateChanged(qreal rate)

Signals the playbackRate has changed to rate.

Note: Notifier signal for property playbackRate.

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

Signal the position of the content has changed to position, expressed in milliseconds.

Note: Notifier signal for property position.

[signal] void QMediaPlayer::seekableChanged(bool seekable)

Signals the seekable status of the player object has changed.

Note: Notifier signal for property seekable.

[slot] void QMediaPlayer::setMedia(const QMediaContent &media, QIODevice *stream = nullptr)

Sets the current media source.

If a stream is supplied; media data will be read from it instead of resolving the media source. In this case the url should be provided to resolve additional information about the media such as mime type. The stream must be open and readable. For macOS the stream should be also seekable.

Setting the media to a null QMediaContent will cause the player to discard all information relating to the current media source and to cease all I/O operations related to that media.

Note: This function returns immediately after recording the specified source of the media. It does not wait for the media to finish loading and does not check for errors. Listen for the mediaStatusChanged() and error() signals to be notified when the media is loaded and when an error occurs during loading.

Since Qt 5.12.2, the url scheme gst-pipeline provides custom pipelines for the GStreamer backend.

player = new QMediaPlayer;
player->setMedia(QUrl("gst-pipeline: videotestsrc ! autovideosink"));
player->play();

If QAbstractVideoSurface is used as the video output, qtvideosink can be used as a video sink element directly in the pipeline. After that the surface will receive the video frames in QAbstractVideoSurface::present().

class Surface : public QAbstractVideoSurface
{
public:
    Surface(QObject *p) : QAbstractVideoSurface(p) { }
    QList<QVideoFrame::PixelFormat> supportedPixelFormats(QAbstractVideoBuffer::HandleType) const override
    {
        // Make sure that the driver supports this pixel format.
        return QList<QVideoFrame::PixelFormat>() << QVideoFrame::Format_YUYV;
    }

    // Video frames are handled here.
    bool present(const QVideoFrame &) override { return true; }
};

player = new QMediaPlayer;
player->setVideoOutput(new Surface(player));
player->setMedia(QUrl("gst-pipeline: videotestsrc ! qtvideosink"));
player->play();

If QVideoWidget is used as the video output and the pipeline contains a video sink element named qtvideosink, current QVideoWidget will be used to render the video.

player = new QMediaPlayer;
videoWidget = new QVideoWidget;
videoWidget->show();
player->setVideoOutput(videoWidget);
player->setMedia(QUrl("gst-pipeline: videotestsrc ! xvimagesink name=\"qtvideosink\""));
player->play();

If the pipeline contains appsrc element, it will be used to push data from stream.

QImage img("images/qt-logo.png");
img = img.convertToFormat(QImage::Format_ARGB32);
QByteArray ba(reinterpret_cast<const char *>(img.bits()), img.sizeInBytes());
QBuffer buffer(&ba);
buffer.open(QIODevice::ReadOnly);
player = new QMediaPlayer;
player->setMedia(QUrl("gst-pipeline: appsrc blocksize=4294967295 ! \
    video/x-raw,format=BGRx,framerate=30/1,width=200,height=147 ! \
    coloreffects preset=heat ! videoconvert ! video/x-raw,format=I420 ! jpegenc ! rtpjpegpay ! \
    udpsink host=127.0.0.1 port=5000"), &buffer);
player->play();

QMediaPlayer *receiver = new QMediaPlayer;
videoWidget = new QVideoWidget;
receiver->setVideoOutput(videoWidget);
receiver->setMedia(QUrl("gst-pipeline: udpsrc port=5000 ! \
    application/x-rtp,encoding-name=JPEG,payload=26 ! rtpjpegdepay ! jpegdec ! \
    xvimagesink name=qtvideosink"));
receiver->play();
// Content will be shown in this widget.
videoWidget->show();

Note: Setter function for property media.

See also media().

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

Signal the state of the Player object has changed.

Note: Notifier signal for property state.

[slot] void QMediaPlayer::stop()

Stop playing, and reset the play position to the beginning.

[signal] void QMediaPlayer::videoAvailableChanged(bool videoAvailable)

Signal the availability of visual content has changed to videoAvailable.

Note: Notifier signal for property videoAvailable.

[signal] void QMediaPlayer::volumeChanged(int volume)

Signal the playback volume has changed to volume.

Note: Notifier signal for property volume.

[virtual] QMediaPlayer::~QMediaPlayer()

Destroys the player object.

[override virtual] QMultimedia::AvailabilityStatus QMediaPlayer::availability() const

Reimplements: QMediaObject::availability() const.

QMediaPlayer::Error QMediaPlayer::error() const

Returns the current error state.

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

Returns the level of support a media player has for a mimeType and a set of codecs.

The flags argument allows additional requirements such as performance indicators to be specified.

const QIODevice *QMediaPlayer::mediaStream() const

Returns the stream source of media data.

This is only valid if a stream was passed to setMedia().

See also setMedia().

void QMediaPlayer::setVideoOutput(QVideoWidget *output)

Attach a QVideoWidget video output to the media player.

If the media player has already video output attached, it will be replaced with a new one.

void QMediaPlayer::setVideoOutput(QGraphicsVideoItem *output)

Attach a QGraphicsVideoItem video output to the media player.

If the media player has already video output attached, it will be replaced with a new one.

void QMediaPlayer::setVideoOutput(QAbstractVideoSurface *surface)

Sets a video surface as the video output of a media player.

If a video output has already been set on the media player the new surface will replace it.

void QMediaPlayer::setVideoOutput(const QVector<QAbstractVideoSurface *> &surfaces)

Sets multiple video surfaces as the video output of a media player. This allows the media player to render video frames on different surfaces.

All video surfaces must support at least one shared QVideoFrame::PixelFormat.

If a video output has already been set on the media player the new surfaces will replace it.

This function was introduced in Qt 5.15.

See also QAbstractVideoSurface::supportedPixelFormats.

QList<QAudio::Role> QMediaPlayer::supportedAudioRoles() const

Returns a list of supported audio roles.

If setting the audio role is not supported, an empty list is returned.

This function was introduced in Qt 5.6.

See also audioRole.

QStringList QMediaPlayer::supportedCustomAudioRoles() const

Returns a list of supported custom audio roles. An empty list may indicate that the supported custom audio roles aren't known. The list may not be complete.

This function was introduced in Qt 5.11.

See also customAudioRole.