Phonon and video for linux (v4l)

[Detlev Casanova]

> Hi Detlev,

Hi Matthias,

> from what I know it should be possible to support v4l in a gstreamer or NMM
> based backend without adding code that directly accesses the v4l device(s).

Do you mean Manhattan Neighborhood Network by MNN ? I don't know what it is 
but I can have a look. 
I think I would have a look at the Gstreamer backend but I thought GStreamer 
was a concurrent to Phonon :S

> There are the xine and avkode backends which could make use of such an
> addition though as neither xine nor ffmpeg provide means to work with v4l.

Which backends are already implemented or going to be implemented ?

> Implementing v4l in its own backend would result in a backend that can only
> be used for v4l and nothing else, i.e. no audio/video playback would work.
> Coming back to the backend idea: I think you understood that Phonon can
> make use of multiple backends at the same time, right? This is not the
> case. One application can only use one backend at a time and as such every
> backend should be as full featured as possible.

So I was thinking wrong :)

> From the little I know about v4l I'd say start with v4l2 and when that's
> done you can still take a look into v4l1.

v4l is now obsolete but some developpers haven't enough time or simply won't 
update their driver to work with v4l2. v4l2 supports more utilities and is 
more stable.

> What features were you thinking of implementing? I'd start with displaying
> the v4l video stream in a VideoWidget (Xv/XShm/OpenGL/whatever) and then
> look into implementing VideoDataOutput (which needs some API love first,
> though).

Of course, streaming is the priority. After that, I think that implementing 
some goodies like the moving head on new Logitech UVC webcams and maybe the 
button to take a snapshot that isn't often used in applications but is 
sometimes usefull for some people.

Detlev.

> On Wednesday 04 October 2006 12:17, Detlev Casanova wrote:
> > I'm going to make a backend for Phonon to support webcam streaming.
> > I won't begin before next week but I have some questions to ask.
> >
> > - I think that implementing 2 different backends for v4l1 and v4l2 would
> > be better than one for both.
> >
> > - In addition, shall we forget v4l1 and put the priority on v4l2 ?
> >
> > - I thought to make a backend by webcam driver but I don't really see the
> > utility as all webcams work near the same way.
> >
> > If you think I'm wrong on any point, just let me know :)
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