Qt Reference Documentation

# Phonon Namespace

The Phonon namespace contains classes and functions for multimedia applications. More...

     #include <Phonon>

This namespace was introduced in Qt 4.4.

## Namespaces

namespace | BackendCapabilities

## Classes

class | AudioDataOutput
class | AudioOutput
class | Effect
class | EffectParameter
class | EffectWidget
class | MediaController
class | MediaNode
class | MediaObject
class | MediaSource
class | ObjectDescription
class | Path
class | SeekSlider
class | VideoPlayer
class | VideoWidget
class | VideoWidgetInterface44
class | VolumeSlider

## Types

typedef | AudioOutputDevice
typedef | AudioOutputDeviceModel
enum | Category { NoCategory, NotificationCategory, MusicCategory, VideoCategory, CommunicationCategory, GameCategory }
enum | DiscType { NoDisc, Cd, Dvd, Vcd }
typedef | EffectDescription
typedef | EffectDescriptionModel
enum | ErrorType { NoError, NormalError, FatalError }
enum | MetaData { ArtistMetaData, AlbumMetaData, TitleMetaData, DateMetaData, ..., MusicBrainzDiscIdMetaData }
enum | ObjectDescriptionType { AudioOutputDeviceType, EffectType }
enum | State { LoadingState, StoppedState, PlayingState, BufferingState, PausedState, ErrorState }
typedef | VideoWidgetInterfaceLatest

## Functions

QString | categoryToString ( Category c )
Path | createPath ( MediaNode * source, MediaNode * sink )
MediaObject * | createPlayer ( Phonon::Category category, const MediaSource & source = MediaSource() )
const char * | phononVersion ()

## Detailed Description

The Phonon namespace contains classes and functions for multimedia applications.

This namespace contains classes to access multimedia functions for audio and video playback. Those classes are not dependent on any specific framework, but rather use exchangeable backends to do the work.

See the Phonon Module page for general information about the framework and the Phonon Overview for an introductory tour of its features.

## Namespaces

### namespace Phonon::BackendCapabilities

The BackendCapabilities namespace contains functions to describe the capabilities of the multimedia backend.

This namespace was introduced in Qt 4.4.

## Classes

### class AudioDataOutput

The AudioDataOutput class provides access to audio data. More...

### class AudioOutput

The AudioOutput class is used to send data to audio output devices. More...

### class Effect

The Effect class is used to transform audio streams. More...

### class EffectParameter

The EffectParameter class describes one parameter of an effect. More...

### class EffectWidget

The EffectWidget class provides a widget to control the parameters of an Effect. More...

### class MediaController

The MediaController class controls optional features of a media file/device. More...

### class MediaNode

The MediaNode class is the base class for all nodes in a media graph. More...

### class MediaObject

The MediaObject class provides an interface for media playback. More...

### class MediaSource

The MediaSource class provides multimedia data for media objects. More...

### class ObjectDescription

The ObjectDescription class provides information about Phonon objects. More...

### class Path

The Path class describes connections between media nodes. More...

### class SeekSlider

The SeekSlider class provides a slider for seeking to positions in media streams. More...

### class VideoPlayer

The VideoPlayer widget is used to perform playback of video. More...

### class VideoWidget

The VideoWidget class provides a widget that is used to display video. More...

### class VideoWidgetInterface44

### class VolumeSlider

The VolumeSlider widget provides a slider that is used to control the volume of an audio output device. More...

## Type Documentation

### typedef Phonon::AudioOutputDevice

This typedef of ObjectDescription describes an audio output device, such as soundcards (with different drivers), sound servers, or other virtual outputs like playback on a different computer on the network.

A list of available devices is given by the backend with Backendcapabilities::availableAudioOutputDevices()

         QList<Phonon::AudioOutputDevice> audioOutputDevices =
                 Phonon::BackendCapabilities::availableAudioOutputDevices();

### typedef Phonon::AudioOutputDeviceModel

provides an item view model containing available audio output devices.

### enum Phonon::Category

Sets the category your program should be listed in in the mixer.

Constant | Value | Description
--- | --- | ---
`Phonon::NoCategory` | `-1` | Will make use of the default device.
`Phonon::NotificationCategory` | `0` | If the sounds produced are notifications (ping, beep and such) you should use this category.
`Phonon::MusicCategory` | `1` | If your application is a music player (like a jukebox or media player playing an audio file).
`Phonon::VideoCategory` | `2` | If the sound is the audio channel of a video.
`Phonon::CommunicationCategory` | `3` | If your applications produces sounds from communication with somebody else (VoIP, voice chat).
`Phonon::GameCategory` | `4` | Sound produced by a computer game should go into this category.
`Phonon::AccessibilityCategory` | `5` | Sounds produced for accessibility (e.g., Text-To-Speech) Holds the largest value of categories.

A Jukebox will set this to Music, a VoIP program to Communication, a DVD player to video, and so on.

Note: These categories can also become useful for an application that controls the volumes automatically, like turning down the music when a call comes in, or turning down the notifications when the media player knows it's playing classical music.

### enum Phonon::DiscType

Enum to identify the media discs supported by MediaObject.

Constant | Value | Description
--- | --- | ---
`Phonon::NoDisc` | `-1` | No disc was selected. This is only useful as a return value from MediaSource::diskType().
`Phonon::Cd` | `0` | Identifies Audio CDs.
`Phonon::Dvd` | `1` | Identifies DVDs (not arbitrary data DVDs, only movie DVDs).
`Phonon::Vcd` | `2` | Identifies Video CDs.

See also MediaSource and MediaObject.

### typedef Phonon::EffectDescription

EffectDescription gives a description of an audio effect. It is a typedef of the ObjectDescription class. Please see its class description for details.

EffectDescription is used to create audio Effects, which can be inserted into a media graph, altering an audio stream.

See also Phonon::ObjectDescription, Capabilities Example, and Media Player.

### typedef Phonon::EffectDescriptionModel

provides a item view model containing available audio effects.

### enum Phonon::ErrorType

This enum describes the severity when an error has occurred during playback.

After a media object has entered the ErrorState, one can query the type of error from MediaObject::errorType(). Note that you should query the error when receiving the MediaObject::stateChanged() signal, because the error type will be lost if the media object leaves the error state.

Constant | Value | Description
--- | --- | ---
`Phonon::NoError` | `0` | No error. MediaObject::errorType() returns this if MediaObject::state() != Phonon::ErrorState.
`Phonon::NormalError` | `1` | An error has occurred with the playback of the current source. It might be possible to continue playback, for instance, if only the audio stream in a video cannot be played back. The media object will then leave the error state again.
`Phonon::FatalError` | `2` | . Something important does not work. Your program cannot continue the playback of the current source, but it might be possible to try another.

See also MediaObject::errorType().

### enum Phonon::MetaData

Provided as keys for Phonon::MediaObject::metaData(). The enum values matches strings defined in the Ogg Vorbis specification

Constant | Value
--- | ---
`Phonon::ArtistMetaData` | `0`
`Phonon::AlbumMetaData` | `1`
`Phonon::TitleMetaData` | `2`
`Phonon::DateMetaData` | `3`
`Phonon::GenreMetaData` | `4`
`Phonon::TracknumberMetaData` | `5`
`Phonon::DescriptionMetaData` | `6`
`Phonon::MusicBrainzDiscIdMetaData` | `7`

### enum Phonon::ObjectDescriptionType

This enum defines the type of information that is contained in a ObjectDescription object.

Constant | Value | Description
--- | --- | ---
`Phonon::AudioOutputDeviceType` | `0` | An audio output device (AudioOutputDevice). This can be soundcards (with different drivers), sound servers, or other virtual outputs like playback on a different computer on the network.
`Phonon::EffectType` | `1` | An audio effect (EffectDescription).

### enum Phonon::State

The state enum describes the different states a media object can take. Several functions of MediaObject are asynchronous, so even if a you have requested a state change through a function call, e.g., through play(), you cannot be sure that the change has taken place before you receive the stateChanged() signal.

A media object can at any time change into any state, regardless of the state it previously had.

Constant | Value | Description
--- | --- | ---
`Phonon::LoadingState` | `0` | After construction it might take a while before the media object is ready to play(). This state is commonly used by backends to initialize the media graph and loading the source. When the object leaves the loading state, it will enter the StoppedState unless an error occurred or another state is requested through a function call, e.g., MediaObject::play().
`Phonon::StoppedState` | `1` | In the stopped state, the media object is ready to play its current media source. The current position in the media stream is then 0.
`Phonon::PlayingState` | `2` | The media object is playing back its media source.
`Phonon::BufferingState` | `3` | The Player is waiting for data to be able to start or continue playing. This state is commonly used to wait for media data over a network connection.
`Phonon::PausedState` | `4` | The media player has currently paused its playback, i.e., it stops playing but keeps the current playback position in the stream.

`Phonon::ErrorState`

`5`

When a media object enters the error state a problem with the playback has occurred. The possible errors are grouped into two categories by Phonon::ErrorType, and the type can be queried through errorType(). A FatalError implies that the playback cannot continue, but one can still try with a new media source. With a NormalError it might be possible to continue playback, and a media object may therefore change state from the ErrorState.

This enum was introduced or modified in Qt 4.4.

See also MediaObject.

### typedef Phonon::VideoWidgetInterfaceLatest

This typedef was introduced in Qt 4.7.

## Function Documentation

### QString Phonon::categoryToString ( Category c )

Returns a (translated) string to show to the user identifying the given Category (c).

### Path Phonon::createPath ( MediaNode * source, MediaNode * sink )

Creates a new Path connecting the two MediaNodes source and sink.

The implementation will automatically select the right format and media type. E.g. connecting a MediaObject and AudioOutput will create a Path object connecting the audio. This might be represented as PCM or perhaps even AC3 depending on the AudioOutput object.

source The MediaNode to connect an output from sink The MediaNode to connect to.

### MediaObject * Phonon::createPlayer ( Phonon::Category category, const MediaSource & source = MediaSource() )

Convenience function to create a MediaObject and AudioOutput connected by a path. The MediaObject return will have source set as its current source and the specified category.

### const char * Phonon::phononVersion ()

Returns the Phonon version.

This function was introduced in Qt 4.5.