Phonon is the Multimedia API for KDE. You should evaluate whether Phonon supplies all you need before looking at frameworks like GStreamer, NMM or Helix. The range of applications goes from full featured media players and capture applications to voice/video chats.
Stable release 4.3
A Basic Overview
In Phonon there are three main concepts: MediaObjects, Paths and Outputs. The MediaObjects control the playback/capture and provide the media data. MediaObjects can be connected to Outputs using Path objects which also allow the insertion of Effect objects between MediaObject and Output.
Phonon is not Unix-specific, and backends have been written for it in order to provide the same functionality on other platforms such as Microsoft Windows or Mac OS X.
Phonon is not designed to have every conceivable multimedia feature, but rather as a simple way to perform common functions of media players. Developers that require more control over a backend than Phonon can provide are recommended to use the native API or the Gstreamer API on Linux.
The idea behind Phonon started at aKademy 2004 in Ludwigsberg, where a new multimedia API had to be chosen to replace aRts. No consensus was reached but a few developers got together and decided to try to develop a new framework with multiple backends. The earlist version was called KDEMM (KDE MultiMedia) and was only supported by JuK and Amarok. Matthias Kretz continued to work single handed on the project as part of his university thesis, The project changed name once more but in February 2006 the name Phonon was finally chosen. The first official release was part of KDE 4.0 in January 2008, the same year Phonon was adopted by Qt and released as part Qt 4.4.
Features:
* Phonon will interface with various backends with what developers call "engines"; each engine works with one specific backend. Each backend will let Phonon control basic functions like play, pause, and seek. Phonon will also support higher level functions such as how tracks fade into each other.[3]
* Phonon will be able to switch multimedia frameworks on the fly. The user will be able to switch between frameworks even while listening to music, with only a slight pause during the switch. This change will also be system wide, affecting all applications that use Phonon, so changing frameworks will be much easier.
* Using Solid, Phonon will give the users greater control over accessories like headsets, speakers, and microphones. An example was given that you could have a VoIP conversation only be played through your headset, but have all other sounds come out through speakers.[3]
* Supported backends on Unix-like systems are xine, Gstreamer, VLC and MPlayer.[4]
* Supported backends under Windows include DirectShow, VLC and MPlayer.
* The backend supported under Mac OS X is QuickTime.
Phonon - Multimedia API for KDE
Common problems
- No sound
There are many causes for this one:- You don't have write access to the audio device. This often happens for people that create a new user to test KDE4 and forget to put him into the audio group, or whatever is required on your distribution.
- Incorrect default ordering of the audio devices. Phonon tries to detect which device is S/PDIF or USB or Modem or whatever and order/hide the devices as needed. But as the information is sometimes missing Phonon cannot always determine the type of device correctly. Take a look at Getting Involved to see how to fix this.
- Missing device entries. This is caused by ALSA/HAL/Solid reporting the exact same name for different devices. This ambiguity results in only one of the devices getting shown. Take a look at Getting Involved to see how to fix this.
- Phonon plays to the wrong device. This is related to the above problem, but if you think the default setting is correct, you just want to change it for your system then open the KDE 4 System Settings and click on the Sound icon. In there you have the possibility to define a preference for devices for different categories of applications. E.g. to change the output device for JuK or Amarok you'd click on the Music category and then move the devices around such that the most preferred device is on top of the list. If this device should fail for some reason (e.g. an unplugged USB device) Phonon will fall back to the next device in the list.
- Phonon causes a crash. Yes, there are still bugs in there. Some people have reported the xine PulseAudio output to crash, so you might want to try to (re)move xine's PulseAudio plugin. You can find it in /usr/lib/xine/plugins//xineplug_ao_out_pulseaudio.so. If it still crashes install all the debug packages (especially for xinelib) for your distri and get a backtrace by attaching gdb with "gdb " and then type "thread apply all bt" at the gdb prompt. Report the bug at bugs.kde.org.
- Devices from /etc/asound.conf or ~/.asoundrc are not listed. Phonon uses a function introduced in alsa-libs 1.0.14 to find those devices. To make this function list your entry you need to add a name hint. E.g.
hint {
show on
description "Name to display for the device"
}
A complete example that adds a new volume control named Phonon to your mixer:
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"
How to download and install phonon.dll, phonon4.dll, libphonon.dll – phonon.dll downloadMany *nix applications are being now ported to Windows and when you try to run them, they display missing phonon.dll file error messages specially if the program is Multimedia kind.
Here are the files you can download :
Download these files and copy them in application’s directory. For example, if you are using KDE 4 Windows, then place these files in KDE4’s bin directory – where all KDE4 executables are placed.
source: Phonon
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