Qt 5.4 Multimedia Backends

For most features, Qt Multimedia builds upon the multimedia framework of the underlying system. Therefore there are several multimedia backends based on different technologies and APIs. The glue between platform specific libraries and Qt Multimedia is contained in a plugin. There are currently three kinds of plugins in Qt Multimedia:

• MediaService plugins, to provide media player, camera, radio, and recording features
• Audio plugins, to provide low-latency audio support
• PlaylistFormat plugins, to support a specific playlist file format

Plugins do not necessarily implement all possible features and different backends have different capabilities. The following tables give an overview of what is supported by each backend in Qt 5.4.

MediaService plugins

Supported media player features by backend

	DirectShow (Windows)	Media Foundation (Windows)	AV Foundation (Mac OS / iOS)	GStreamer (Unix)	Android	BlackBerry
MediaPlayer control	X	X	X	X	X	X
URL source (local and remote)	X	X	X	X	X	X
Stream source	X	X		X
Metadata	X	X	partial	X	X	X
Playback rate	X	X	X	X		X
Track selection				X
HW decoding		Only when using Angle	X		X	X
Video window control	X	X	X	X		X
Video widget control			X	X
Video renderer control (includes OpenGL textures)	X	X	X (only Mac OS)	X	X	X
Audio probe		X		X
Video Probe		X		X

Supported camera features by backend

	DirectShow (Windows)	Media Foundation (Windows)	AV Foundation (Mac OS / iOS)	GStreamer (Unix)	Android	BlackBerry
Camera control	X		X	X	X	X
Video window control				X
Video widget control	X			X
Video renderer control (includes OpenGL textures)	X		X	X	X	X
ViewFinder settings				resolution		resolution, framerate, pixel format
Image capture	X		X	X	X	X
Capture destination	File		File	File, Buffer	File, Buffer	File, Buffer
Image settings				resolution	resolution, quality	resolution, quality
Zoom				X	X	X
Flash				X	X	X
Focus				only focused notification	mode, custom point	mode, custom point
Exposure				Scene mode, compensation, ISO, aperture, ShutterSpeed	Scene mode, compensation	Scene mode
Image Processing				White Balance, Contrast, Brightness, Saturation,	White Balance	White Balance
Locks				Focus	Focus, Exposure, White Balance	Focus, Exposure, White Balance

Supported recording features by backend

	DirectShow (Windows)	Media Foundation (Windows)	AV Foundation (Mac OS / iOS)	GStreamer (Unix)	Android	BlackBerry
Record camera			X	X	X	X
Record audio	Fallback to audio backend	Fallback to audio backend	Fallback to audio backend	X	X	Fallback to audio backend
MetaData writer				X
Audio encoder settings				X	X	X
Video encoder settings				X	X	X
Container settings				X	X

Supported audio decoding features by backend

	DirectShow (Windows)	Media Foundation (Windows)	AV Foundation (Mac OS / iOS)	GStreamer (Unix)	Android	BlackBerry
Decode audio		X		X

Audio plugins

Audio backends implement QAudioInput, QAudioOutput, QAudioDeviceInfo and QSoundEffect

Here is the list of the current audio backends:

• Windows Multimedia
• CoreAudio (Mac OS / iOS)
• PulseAudio (Unix)
• Alsa (Unix)
• OpenSL ES (Android)
• QNX