Video Player

Introduction

The VideoPlayer_C module enables video playback functionality using Qt’s QMediaPlayer, with support for rendering via a QAbstractVideoSurface. This class provide functionality to integrate video player in qml.

Supported Features:

Video playback: .mp4, .avi, etc.
Play / Pause / Stop control
Duration and position tracking
Surface rendering via QAbstractVideoSurface
Metadata extraction
QML integration with Q_PROPERTY and Q_INVOKABLE
Dynamic creation and destruction of media player

Initialization

VideoPlayer_C* m_videoPlayer = std::make_shared<AudioVideoPlayer_CPlayer_C>(this);
m_engine->rootContext()->setContextProperty("VideoPlayer_Q", m_videoPlayer.get());

Internally, the constructor sets the media to a sample file like /rw_data/sample_video.mp4.

Public API Functions

`void play()`

Starts or resumes video playback.

m_videoPlayer->play();

`void pause()`

Pauses the video.

m_videoPlayer->pause();

`void stop()`

Stops playback and resets internal state.

m_videoPlayer->stop();

`void setMediaPosition(int newPosition)`

Seeks to a specified position in milliseconds.

m_videoPlayer->setMediaPosition(5000);  // 5 seconds

`void initMediaPlayer()`

Initializes the media player instance if it was previously destroyed. Also reattaches the video surface and restores last playback state.

`void destroyMediaPlayer()`

Destroys the player and frees resources. Useful for switching contexts or releasing video hardware.

`void setFormat(int width, int height, int format)`

Sets the video format for the rendering surface. (Currently not fully used in source code)

`void getMetaData()`

Fetches and logs all available metadata from the media file.

m_videoPlayer->getMetaData();

Properties (Q_PROPERTY)

Property	Type	Description
`videoSurface`	`QAbstractVideoSurface*`	Surface used for rendering frames.
`position`	`int`	Current playback position (ms).
`duration`	`int`	Total media duration (ms).
`state`	`QMediaPlayer::State`	Current playback state.

Slots

`void setVideoSurface(QAbstractVideoSurface *surface)`

Attaches a new video rendering surface to the media player.

`void onPositionChanged(qint64 value)`

Updates the current playback position.

`void onDurationChangeed(qint64 value)`

Updates the media duration.

`void onStateChanged(QMediaPlayer::State value)`

Updates the player’s internal state.

`void onNewVideoContentReceived(const QVideoFrame &frame)`

Receives raw frames and pushes them to the video surface.

// Called when a new frame is received
m_surface->present(frame);

`void onMediaStatusChanged(QMediaPlayer::MediaStatus status)`

Handles changes in media status like buffering, loaded, etc.

`void setPosition(int position)`

Sets the current playback position and emits positionChanged.

`void setDuration(int duration)`

Sets media duration and emits durationChanged.

`void setState(QMediaPlayer::State state)`

Sets player state and emits stateChanged.

Signals

Signal	Description
`void frameFinished()`	Emitted when a video frame is completed.
`void positionChanged(int)`	Emitted when playback position updates.
`void durationChanged(int)`	Emitted when total video duration changes.
`void stateChanged(State)`	Emitted on play/pause/stop state change.

Usage Example

Basic Video Playback

m_videoPlayer->play();

Pause / Stop

m_videoPlayer->pause();
m_videoPlayer->stop();

Seek to Position

m_videoPlayer->setMediaPosition(120000);  // Jump to 2 minutes

Dynamic Initialization / Destruction

m_videoPlayer->destroyMediaPlayer();
m_videoPlayer->initMediaPlayer();

Metadata Logging

m_videoPlayer->getMetaData();  // Logs all metadata keys & values

Connecting to Signals

QObject::connect(m_videoPlayer, &VideoPlayer_C::positionChanged, [](int pos){
    qDebug() << "Position: " << pos;
});

Default Video Path Resolution

The constructor attempts to automatically resolve a path like:

/rw_data/sample_video.mp4

$HOME/sample_video.mp4

It uses getcwd() and conditional compilation with OS_EMBEDDED to resolve it appropriately.

Usage of `VideoPlayer_Q` with `VideoOutput`

In this code, you’re using the VideoOutput element to display video content from a backend media player object named VideoPlayer_Q.

VideoOutput { id: videoOut source: VideoPlayer_Q anchors.fill: parent }

What’s Happening:

VideoOutput is a built-in QML type that renders video frames.
source: VideoPlayer_Q connects it to a video player object.
When you call VideoPlayer_Q.play(), the video will appear inside this VideoOutput.

Video Player

Introduction

Supported Features:

Initialization

Public API Functions

void play()

void pause()

void stop()

void setMediaPosition(int newPosition)

void initMediaPlayer()

void destroyMediaPlayer()

void setFormat(int width, int height, int format)

void getMetaData()