Qt 5.4 Multimedia Backends

Qt 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

{background:#009900}. |. |. 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 | | |

h4. Supported camera features by backend

{background:#009900}. |. |. 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

{background:#009900}. |. |. 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 | |

h4. Supported audio decoding features by backend {background:#009900}. |. |. 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