[Qt-interest] Fade In/Out Video with Phonon

[Josiah Bryan]

Oliver.Knoll at comit.ch wrote:
> Josiah Bryan wrote on Monday, February 22, 2010 1:36 PM:
> 
>>> ...
>>> - render the video frame on some "surface" (QImage, OpenGL textured
>>> rectangle, ...)
>>> - set the alpha value accordingly (1.0 down to 0.0)
>>> - render that "surface" on top of an existing one (black background,
>>> other video frame)
>>>
>> Right again - all well and good, but how to you actually get the
>> individual frames from the video to do your own rendering? I've yet
>> to find a slot like, say, MediaObject::newImage(const QImage&) that
>> fires so I can render the image.  
> 
> Even in the danger of destroying your plans of using Phonon I just read this in a related topic thread: "[...] but phonon module doesn't allow acquiring a frame from a video file to process (cut-copy frames or some image processing filters etc.). In this manner, ffmpeg and mplayer nearly solve all problems [...]" (thread: directshow vs mplayer or ffmpeg, OP: Mehmet Kaplan, date: today).

Yes, I saw that message come through and I've been waiting for someone 
with deeper knowledge than my own to reply to it.

> The good news seems to be that at least with ffmpeg you have access to individual frames (at it might not be that hard to embed it into a QWidget - it has been done before).

Agreed. In fact, that is what I'm currently using at the moment to 
render MPEG video loops as backgrounds for presentations in Qt. However, 
I'm having a bear of a time getting the CPU usage down and getting audio 
support working - hence why I was hoping to use Phonon.

-- 

-=-=-=-=-=-=-=-=-=-=-=-=-
Josiah Bryan
Productive Concepts, Inc.
jbryan at pciint.com
(765) 964-6009, ext. 224