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
Add audio playback to a scene | |
Access viewfinder frames, and take photos and movies | |
An interface for capturing camera images | |
An interface for exposure related camera settings | |
An interface for flash related camera settings | |
An interface for focus related camera settings | |
An interface for camera capture related settings | |
Controls video recording with the Camera | |
Add media playback to a scene | |
For specifying a list of media to be played | |
Defines an item in a Playlist | |
Provides a global object with useful functions from Qt Multimedia | |
Access RDS data from a QML application | |
Type provides a way to play sound effects in QML | |
Simple control over torch functionality | |
A convenience type for showing a specified video | |
Render video or camera viewfinder |
The following types are accessed by using Qt Audio Engine:
import QtAudioEngine 1.15
Defines a non-linear attenuation curve for a Sound | |
Defines a linear attenuation curve for a Sound | |
Control all active sound instances by group | |
Organize all your 3d audio content in one place | |
Control global listener parameters | |
Load audio samples, mostly .wav | |
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 | |
Define a variety of samples and parameters to be used for SoundInstance | |
Play 3d audio content |
Multimedia Classes
Contains enums used by the audio classes | |
Represents a collection of audio samples with a specific format and sample rate | |
Provides identifiers for meta-data attributes | |
Contains miscellaneous identifiers used throughout the Qt Multimedia library |