Multimedia

Multimedia support in Qt is provided by the Qt Multimedia module. The Qt Multimedia module provides a rich feature set that enables you to easily take advantage of a platform's multimedia capabilities such as media playback and the use of camera and radio devices.

Features

Here are some examples of what can be done with Qt Multimedia APIs:

Access raw audio devices for input and output
Play low latency sound effects
Play media files in playlists (such as compressed audio or video files)
Record audio and compress it
Tune and listen to radio stations
Use a camera, including viewfinder, image capture, and movie recording
Play 3D positional audio with Qt Audio Engine
Decode audio media files into memory for processing
Accessing video frames or audio buffers as they are played or recorded

Multimedia Components

Qt's multimedia APIs are categorized into four main components. More information (including background information and class references) is available here:

Multimedia Recipes

For some quick recipes, look at the overviews above and consult this table:

Use case	Examples	QML Types	C++ Classes
Playing a sound effect			QSoundEffect
Playing low latency audio	audioinput, spectrum		QAudioOutput
Playing encoded audio (MP3, AAC etc)	player	Audio, MediaPlayer	QMediaPlayer
Accessing raw audio input data	spectrum, audioinput		QAudioInput
Recording encoded audio data	audiorecorder		QAudioRecorder
Discovering raw audio devices	audiodevices		QAudioDeviceInfo
Video Playback	player, qmlvideo, qmlvideofx	MediaPlayer, VideoOutput, Video	QMediaPlayer, QVideoWidget, QGraphicsVideoItem
Video Processing	qmlvideofx	MediaPlayer, VideoOutput	QMediaPlayer, QAbstractVideoSurface, QVideoFrame
Listening to the radio	declarative-radio	Radio, RadioData	QRadioTuner, QRadioData
Accessing camera viewfinder	camera, declarative-camera	Camera, VideoOutput	QCamera, QVideoWidget, QGraphicsVideoItem
Viewfinder processing		Camera, VideoOutput	QCamera, QAbstractVideoSurface, QVideoFrame
Capturing photos	camera, declarative-camera	Camera	QCamera, QCameraImageCapture
Capturing movies	camera, declarative-camera	Camera	QCamera, QMediaRecorder
3D sound sources		Audio Engine	AudioEngine, Sound

Limitations

The Qt Multimedia APIs build upon the multimedia framework of the underlying platform. This can mean that support for various codecs or containers can vary between machines, depending on what the end user has installed.

Advanced Usage

For developers wishing to access some platform specific settings, or to port the Qt Multimedia APIs to a new platform or technology, see Multimedia Backend Development.

Changes from Previous Versions

If you previously used Qt Multimedia in Qt 4, or used Qt Multimedia Kit in Qt Mobility, please see Changes in Qt Multimedia for more information on what changed, and what you might need to change when porting code.

Reference Documentation

QML Types

The QML types are accessed by using:

import QtMultimedia 5.8

Video	A convenience type for showing a specified video
Audio	Add audio playback to a scene
MediaPlayer	Add media playback to a scene
Camera	Access viewfinder frames, and take photos and movies
CameraCapture	An interface for capturing camera images
CameraExposure	An interface for exposure related camera settings
CameraFlash	An interface for flash related camera settings
CameraFocus	An interface for focus related camera settings
CameraImageProcessing	An interface for camera capture related settings
CameraRecorder	Controls video recording with the Camera
QtMultimedia	Provides a global object with useful functions from Qt Multimedia
Playlist	For specifying a list of media to be played
PlaylistItem	Defines an item in a Playlist
Radio	Access radio functionality from a QML application
RadioData	Access RDS data from a QML application
Torch	Simple control over torch functionality
SoundEffect	Type provides a way to play sound effects in QML
VideoOutput	Render video or camera viewfinder

The following types are accessed by using Qt Audio Engine:

import QtAudioEngine 1.1

AttenuationModelInverse	Defines a non-linear attenuation curve for a Sound
AttenuationModelLinear	Defines a linear attenuation curve for a Sound
AudioCategory	Control all active sound instances by group
AudioEngine	Organize all your 3d audio content in one place
AudioListener	Control global listener parameters
AudioSample	Load audio samples, mostly .wav
PlayVariation	Define a playback variation for sounds. So each time the playback of the same sound can be a slightly different even with the same AudioSample
Sound	Define a variety of samples and parameters to be used for SoundInstance
SoundInstance	Play 3d audio content

Multimedia Classes

QStaticText	Enables optimized drawing of text when the text and its layout is updated rarely
QGraphicsEffect	The base class for all graphics effects
QAudio	Contains enums used by the audio classes
QAudioBuffer	Represents a collection of audio samples with a specific format and sample rate
QAudioBuffer::StereoFrame	Simple wrapper for a stereo audio frame
QAudioDecoder	Allows decoding audio
QAudioDeviceInfo	Interface to query audio devices and their functionality
QAudioInput	Interface for receiving audio data from an audio input device
QAudioOutput	Interface for sending audio data to an audio output device
QAudioProbe	Allows you to monitor audio being played or recorded
QAbstractAudioDeviceInfo	Base class for audio backends
QAbstractAudioInput	Access for QAudioInput to access the audio device provided by the plugin
QAbstractAudioOutput	Base class for audio backends
QAudioSystemPlugin	Abstract base for audio plugins
QSound	Method to play .wav sound files
QSoundEffect	Way to play low latency sound effects
QCameraExposure	Interface for exposure related camera settings
QCameraFocus	Interface for focus and zoom related camera settings
QCameraFocusZone	Information on zones used for autofocusing a camera
QCameraImageCapture	Used for the recording of media content
QCameraImageProcessing	Interface for image processing related camera settings
QCameraInfo	General information about camera devices
QCameraViewfinderSettings	Set of viewfinder settings
QMediaContent	Access to the resources relating to a media content
QMediaPlayer	Allows the playing of a media source
QMediaPlaylist	List of media content to play
QMediaResource	Description of a media resource
QMediaBindableInterface	The base class for objects extending media objects functionality
QMediaControl	Base interface for media service controls
QMediaMetaData	Provides identifiers for meta-data attributes
QMediaObject	Common base for multimedia objects
QMediaService	Common base class for media service implementations
QMediaTimeInterval	Represents a time interval with integer precision
QMediaTimeRange	Represents a set of zero or more disjoint time intervals
QMultimedia	Contains miscellaneous identifiers used throughout the Qt Multimedia library
QRadioData	Interfaces to the RDS functionality of the system radio
QRadioTuner	Interface to the systems analog radio device
QAudioRecorder	Used for the recording of audio
QAudioEncoderSettings	Set of audio encoder settings
QImageEncoderSettings	Set of image encoder settings
QVideoEncoderSettings	Set of video encoder settings
QMediaRecorder	Used for the recording of media content
QAbstractVideoFilter	Represents a filter that is applied to the video frames received by a VideoOutput type
QVideoFilterRunnable	Represents the implementation of a filter that owns all graphics and computational resources, and performs the actual filtering or calculations
QAbstractVideoSurface	Base class for video presentation surfaces
QVideoProbe	Allows you to monitor video frames being played or recorded
QVideoSurfaceFormat	Specifies the stream format of a video presentation surface
QGraphicsVideoItem	Graphics item which display video produced by a QMediaObject
QVideoWidget	Widget which presents video produced by a media object
QAudioFormat	Stores audio stream parameter information
QCamera::FrameRateRange	A FrameRateRange represents a range of frame rates as minimum and maximum rate
QCamera	Interface for system camera devices
QAbstractPlanarVideoBuffer	Abstraction for planar video data
QAbstractVideoBuffer	Abstraction for video data
QVideoFrame	Represents a frame of video data

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