Phonon

Sebbene Phonon sia sviluppato principalmente pensando agli sviluppatori software e sia progettato concentrandosi sulla facilità di sviluppo, fornisce anche parecchie funzionalità e vantaggi per l'utente finale.

Funzioni

• Configurazione centralizzata di audio e video: la configurazione dell'hardware e dei framework multimediali è offerta in un'unica finestra centralizzata in modo che le applicazioni non debbano re-implementare finestre di configurazione specializzate.
• Struttura orientata allo scopo: invece di chiederti di selezionare uscite audio speciali per applicazioni specifiche, le applicazioni Phonon descrivono il tipo di uscita audio prodotta (notifiche, musica, video, comunicazione) e questo ti permette di selezionare individualmente le uscite per queste categorie.
• Selezione automatica del dispositivo: l'utilizzo di dispositivi audio e video collegabili come auricolari USB o Bluetooth è oggi quasi costante. Phonon opera sulle informazioni e segnali provenienti da Solid, il sottosistema hardware di KDE, e utilizza automaticamente i nuovi dispositivi.

Risoluzione dei problemi

Nessun suono

Ci sono molte possibili ragioni per la mancanza completa dell'audio.

Ordinamento predefinito dei dispositivi non corretto

Phonon cerca automaticamente di ordinare i dispositivi audio utilizzando le informazioni disponibili e un database con informazioni sui dispositivi di cui è corredato. Sfortunatamente questo sistema non sempre funziona, ma leggi Come collaborare per informazioni su come puoi aiutare a sistemare problemi di questo tipo.

Missing device entries

This can be caused by Solid or other system libraries reporting the same name for several devices, which makes Phonon unable to properly display these devices to you. Please see Getting Involved on how to help fix this.

Unable to access audio device

If your user account has insufficient permissions to access the audio device, Phonon will be unable to play sound. Please consult the documentation of your distribution on how to ensure that your user account is properly set up (make sure that your user account is a part of the audio user account group).

Sound out of the wrong device

This is related to the point above this. Also make sure that the correct device is listed at the top in the Sound and Video area of System Settings. In case an audio device isn't available (an USB-headset unplugged, for example), Phonon will attempt the next device in the list.

Phonon causes a crash

Please search on bugs.kde.org to see if the bug is already reported. If it isn't, please report it, and if it already exists but you have new information not already reported, please add your new information to the existing report.

Devices from ~/.asoundrc or /etc/asound.conf are not listed

Make sure you have a name hint set for your device. An example of a complete device entry, with a hint:

pcm.softvolPhonon {
     type softvol
     slave.pcm "default:CARD=0"
     control {
        name "Phonon"
        card 0
     }
     min_dB -51.0
     max_dB 0.0
     resolution 100
     hint {
        show on
        description "My Soundcard with extra Volume Control"
     }
}

Backend libraries

Phonon itself is just a thin shim, and makes use of backend libraries to provide the actual functionality.

• Phonon-Xine: This is the first proper backend for Phonon.
• Phonon-VLC: VLC is a very popular cross-platform media player, and it is written using a multimedia library named libvlc, which we also use to power a backend for Phonon. This is also under active development, and is receiving a lot of work from both VLC and Phonon developers.
• Phonon-GStreamer: GStreamer is a multimedia library from the GNOME project. This backend is currently the recommended Kubuntu backend, although it is rather unstable.
• Phonon-DS9: This is a native backend for Microsoft Windows utilizing DirectShow 9.
• Phonon-QT7: This is a native backend for Mac OS X, utilizing QuickTime 7.
• Phonon-MPlayer: This is a third-party backend for Phonon, utilizing the popular mplayer application for playback.
• Phonon-NMM: This is an abandoned and unmaintained backend started by the Graphics Lab at Saarland University and Motama.

Getting Involved

There are several ways you can get involved as a user.

• Reporting audio hardware: Download the soundcardinfo.sh script and run it, and attach the output to bugs.kde.org. This enables us to add your hardware information to our audio device database.
• Quality assurance: Simply run and use Phonon, and report bugs and irregularities to the developers.
• Documentation: You can help expand this page and other Phonon documentation. It doesn't take much to help, and it helps!
• Promotion: Spreading the word about KDE and Phonon is always welcome.
• Appreciation: Encouraging words can help lift the spirits of weary multimedia developers way beyond the clouds, when faced with nasty bugs and other challenges. Positive emails, messages on IRC, beer, pizza, gadgets and other developer fuel is very welcome!