[gst-devel] newbie: multiple webcams?

[Gerry Deckert]

Stefan,

   Thanks, I'll give that a try.  Missed that one when I was searching for video-related plugins.  Any other pointers you could give me?


   Cheers,


   Gerry


--- On Thu, 8/7/08, Stefan Kost <ensonic at hora-obscura.de> wrote:

> From: Stefan Kost <ensonic at hora-obscura.de>
> Subject: Re: [gst-devel] newbie: multiple webcams?
> To: "Discussion of the development of GStreamer" <gstreamer-devel at lists.sourceforge.net>
> Date: Thursday, August 7, 2008, 1:30 AM
> hi,
> 
> have you tried input-selector from gst-plugin-bad?
> 
> Stefan
> 
> Gerry Deckert schrieb:
> > Hi all,
> >
> >    I'm working on a Gstreamer / Python / Gtk
> project to debut at Burning Man in a few weeks, and I'm
> hoping to get some suggestions, insight, and pointers to
> examples.  I'm almost completely new to Gstreamer and
> the Python bindings, but I have gone through the App
> development manual and the Pygstreamer Tutorial.  I'm
> amazed at the speed and flexibility, and I'm convinced
> it's the right way to go with my project.
> >    Here's what I'm trying to do:  I want to
> take input from multiple usb webcams (v4lsrcs) at the same
> time, display video in a window from just one at a time, and
> have the ability to switch the feed smoothly from camera to
> camera.  Why would I want to do this you ask?  So I can set
> up a ring of cameras and create a bullet-time dance cage, of
> course.  :)
> >    I cobbled together something from various examples
> that more or less works, but I'm sure there's a
> better approach.  My initial attempt involved detaching and
> attaching cameras directly to xvimagesink, but this took too
> long for a smooth transition.  In my current setup, each
> camera is fed through its own videobox, all the videoboxes
> connect to a single videomixer, and the videomixer goes
> through ffmpegcolorspace to xvimagesink.  All the cameras
> are running at the same time, and I choose between them by
> setting the alpha channel on the videobox of the desired
> camera to 1 while all the others are 0.  This results in
> smooth switching, but I'm sure is not a good use of
> resources.  
> >    So, with that, I have lots of questions.  Is there
> a way to switch between sinks on the videomixer to
> accomplish the same effect?  Is there a fast way to turn the
> cameras on and off, or should I try turning them on and off
> in groups?  How could I enable recording of the video
> that's coming out?  I'm guessing I want to use a tee
> element, but how do I enable it on the fly?  What about
> toggling on/off some of the effectv plugins?  How could I
> grab single frames from the cameras?  I don't have a
> good understanding of what's involved in modifying the
> pipeline on the fly.  Is there some documentation or are
> there some examples anyone could point me to?  Suggestions? 
> Any help would be greatly appreciated!
> >
> >
> >    Regards,
> >
> >
> >    Gerry
> >
> >
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