[Qt-interest] Intercepting Phonon VideoWidget frames as they are pushed

[Richard Baron Penman]

hi,

I am also hoping for such a solution because I've found phonon much easier
to install cross platform than Quicktime/ffmpeg. If you figure it out please
post back here!

Richard


On Sun, Mar 22, 2009 at 2:49 PM, Trent Tuggle <Trent at tuggle.org> wrote:

> Hey...
>
> Thanks for the quick reply!
>
> I have tried using ffmeg directly and am also considering using
> Quicktime directly but there are drawbacks to each approach. Phonon is
> so attractive because its a wrapper around what are arguably the best
> libraries on each platform.  Probably if i fail to capture a
> VideoWidget I will probably do just that.  My current goal just seems
> so close!
>
> -Trent Tuggle
>
>
>
> On Mar 21, 2009, at 11:46 AM, Pavel Koshevoy <pavel at aragog.com> wrote:
>
> > Have you considered using ffmpeg directly, instead of going through
> > all
> > the phonon/DirectShow/QuickTime/gstreamer/etc... layers and
> > implementing
> > a workaround just so you can get the frames?
> >
> >    Pavel
> >
> >
> > Trenton Tuggle wrote:
> >> I have an interesting challenge I've been working on:
> >>
> >> I'm working on video processing, and am investigating using Phonon
> >> for
> >> platform-independent back-ends.
> >>
> >> My interest is not the usual, though -- I have little interest in
> >> showing the video on-screen (although that would be nice, also) but
> >> primarily, I'm interested in obtaining the video frames.
> >>
> >> Now I know it's easy to render() a widget (such as VideoWidget)
> >> onto a
> >> pixmap or other, but I'm really interested in obtaining the frames in
> >> a more automated way -- such as getting a signal when the next frame
> >> is ready, etc.  My thought is that since VideoWidget can be embedded
> >> in a graphics scene, it must be possible to intercept its painting
> >> events and redirect it to a qimage or something: but so far I've
> >> failed.
> >>
> >> So that's my question: how can I embed a VideoWidget in something
> >> that
> >> can intercept paint events, redirect them to a QImage, then signal a
> >> processor that a frame is ready for processing?
> >>
> >> I've tried stuff along these lines:
> >>
> >> http://www.kdedevelopers.org/node/3644
> >>
> >> The thought was that I'll create a Phonon path to play on a
> >> VideoWidget embedded in something like that which would capture the
> >> frame, then signal my processor....
> >>
> >> But so far, I've been unable to get the widget I create to receive
> >> any
> >> paint events, or intercept anything at all -- it doesn't even get
> >> resized properly when a video is loaded!
> >>
> >> If anyone has any advice or input on this, I'd really appreciate it!
> >>
> >> Thanks in advance!
> >>
> >> Trent Tuggle <Trent at Tuggle.Org>
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> >>
> >
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