- Qt 6.8
- Qt Multimedia
- Qt Multimedia on WebAssembly
- Qt 6.8.3 Reference Documentation

# Qt Multimedia on WebAssembly

This page covers the availability of Qt Multimedia features on WebAssembly.

## Limitations

Due to the asynchronous nature of javascript, some features such as getting the list of QMediaDevices, will not be readily available and may take some time to request permissions and gather the list of devices. The audioInputsChanged, audioOutputsChanged and videoInputChanged signals from QMediaDevices class will be emitted when they are available.

Playing video currently works by using a html 2d context, so all operations are on the CPU.

Performance is acceptable, although there is a copy on every frame, so it may be less performant than desktop platforms when playing hi-def video.

Using and selecting different Codecs/video formats have not yet been tested, but whatever video formats the browser supports will most likely work.

Playing data from a stream (using `setSourceDevice(QIODevice*)`), instead of fetching a URL, isn't supported.

Some advanced features may or may not work at this time.

Files can be served from the/any web server, respective of CORS. Because of the limited size of local file storage, playing local files is discouraged.