Phonon: Multimedia in KDE 4

After many months of work on the new Multimedia API for KDE 4 it is time to
finally announce Phonon. Phonon will
provide a task oriented API for multimedia, making it easy for KDE
applications to use media playback and capture functionality (and more)
resulting in application developers being free to concentrate on the user
interface aspects. The number of possibilities to integrate multimedia into the
desktop experience
make Phonon especially interesting.

Phonon uses exchangeable backends to do the real work which can be implemented using GStreamer, NMM, Xine, Helix or whatever else you can come up with. In turn KDE applications do not need to develop media engine abstractions anymore as Phonon provides it for them.

The folks from Motama have already started work on a Phonon-NMM backend and we will give a joint presentation at
upcoming LinuxTag this year (also see their announcement). Meet us on Saturday, May 6th at 10:00 in Hall 6.2 or later at the KDE booth.

As there is still a lot of work that needs to be done until Phonon is released with KDE 4.0 it is a great chance to get involved now, for example doing a Google Summer of Code project.

Phonon is supported by basysKom GmbH, Motama GmbH, KDE-NL who are organising a KDE Multimedia meeting and most importantly the community for providing feedback & code.


While central configuration should of course be available, it should also be possible to override that per application, imho. It would be unfortunate, if the user would be forced to go with one backend for all (KDE) applications, instead being able to choose backend X for app A and Y for app B. There can be differences in functionality, e.g. supported (or licensed) codecs needed for a specific task compared to less cpu usage by another backend that suffices for usual tasks.

By Carlo at Fri, 2006/04/28 - 5:00am

All applications which ship with KDE should use one single interface backend.

By gerd at Fri, 2006/04/28 - 5:00am

I think I said already that this is probably not a good idea, since it would restrict all applications, which use Phonen to the limitations of one backend.

By Carlo at Fri, 2006/04/28 - 5:00am

But having multiple backends concurrently will lead to the problem mentioned above, where one backend hogs the soundcard and the other backend can't play any sounds. For example, you won't be able to hear system notifications (beeps or gongs) that are outputted via one backend if you are watching a movie that is outputted via the other backend.

By ac at Fri, 2006/04/28 - 5:00am

Re-read earlier comments, that´s a sound server issue. If you have an uptodate linux system with alsa then it´s not an issue, else make sure to set up the backends to use the _same_ sound server.

By koos at Fri, 2006/04/28 - 5:00am

I was wondering if phonon willmake it possible to have per-application settings for things like volumne and/or soundcard and channel on that card? I think something like that would be very usefull, enabling one to route system sounds to small speakers connected to the simple on board sound system, the music you are playing to the amplifier connected to your additional soundcard and your VoIP session to your headset, while giving them all their own volumne....

By Andre Somers at Fri, 2006/04/28 - 5:00am

theoretically, yes. and actually, i think they will implement these things.

By superstoned at Fri, 2006/04/28 - 5:00am

How will phonon deal with multiple soundcards? I prefer to be able to choose which soundcard to use on a per-application basis. Will this be possible with phonon?

By Mere at Fri, 2006/04/28 - 5:00am

theoretically, yes. and actually, i think they will implement these things.


By superstoned at Fri, 2006/04/28 - 5:00am

as the site says, the mixer is kind of pain. It strikes me that this should be broken into 2 parts; the input and the output. As in 2 different view or even 2 different apps.
For the output, it should be nothing more than a balance and a total output. So imagine a trackball (a circle with a pin) where you can push the output and a side volume for total volume. Nice and simple; that is, set the volume, and then move the pin. Push it straight forward, and all the output goes to front. Push to right side, and output goes to right front/right back. Push it to NE corner and you only get right front corner. Finally, borrow from KNOB. that is a SIMPLE way to turn total volume up and down, with a quick mute. One last thing would be a checkbox to indiacte that the volume is either avg or max vol. i.e. hate it when I set the vol. and then an add comes increasing the DB by 10. (or 2 slides, but...).

For the input, it sounds like you have the right idea; class of apps (defaults), followed by individual app overrides. It would be nice to provide some filtering ala arts (the idea was awesome; the imp was slow).

By a.c. at Fri, 2006/04/28 - 5:00am

It would also be nice if we can have sound at the login/screensaver. that way, either a screen saver can display or even a radio play in the background. I was even thinking that I might feed a baby monitor through it (for the parents here).

By a.c. at Fri, 2006/04/28 - 5:00am

You can hack into the configuration of XDM/KDM and make a soundapplication start with it.

By AC at Sun, 2006/04/30 - 5:00am

During FISL I was present on a presentention of Helio de Castro who talked about Phonon, so I kind if knew already about this, and I even can answer the major question about it:
No! It's not a engine like gstreamer, arts and such, it's more like a layer, you make your program for the layer, and it will call the apropriate (or chosen) audio engine. It's kind of like what amarok does for playing audio files.

IMHO it's a good idea to make KDE NOT try to solve the linux audio/video problem, let someone else do it, because they probally do a better job, because they don't have an entire desktop to care.

By Iuri Fiedoruk at Fri, 2006/04/28 - 5:00am

Hi and congrats for the work torwards KDE 4.0.

I just wanted to point out a small typo in http://phonon.kde.org/cms/1030 . In the last paragraph it says "There will probably more when Phonon", but probably should say "There will probably be more when Phonon".


By Hugo Costelha at Fri, 2006/04/28 - 5:00am

Thanks. I just fixed it.

By Matthias Kretz at Tue, 2006/05/02 - 5:00am

Excellent designs on these websites, but on a side issue: I think it would be nicer if these sites adopted "...it's a Free Software project" as the tagline on the bottom (as http://kde.org does).

By apokryphos at Sat, 2006/04/29 - 5:00am

Open source desktop is the term used for the conferences etc. It wasn't made up for the sites. :)

By Ian Monroe at Sat, 2006/04/29 - 5:00am

Not sure I follow... not saying the term was made up for the site, just think it'd be nicer to have "free software" instead of "open source".

By apokryphos at Sun, 2006/04/30 - 5:00am

Why would it be nicer?

By AC at Sun, 2006/04/30 - 5:00am

because for many of us, the 'free' aspect is an important reason why we use Linux and KDE. also, it is just a wider and more encompassing term. KDE and linux are not *just* OSS, but they are FREE as in speech.

“In a world where speech depends on software, free speech depends on free software.” — Don Marti jr.

this is for me, and many other linux users, a important point. i value my freedom of speech, and i'm committed to keeping it.

By superstoned at Sun, 2006/04/30 - 5:00am

The KDE.org site has no such tagline, as far as I can see.

By Martin at Tue, 2006/05/02 - 5:00am