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

[Oliver.Knoll at comit.ch]

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).

I am not sure whether that means "the Phonon API itself does not provide such funtionallity (as to aquire a single frame)" or "the Qt API wrapped over the Phonon API does not provide such a functionallity" - but practically that means the same to you.

So it seems to me that "Phonon is all fine for convenient playback of video/audio - but that's it! Sorry, no editing!"

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).


Good luck, Oliver
-- 
Oliver Knoll
Dipl. Informatik-Ing. ETH
COMIT AG - ++41 79 520 95 22