[Kdenlive-devel] transitions

[Jason Wood]

On Sunday 18 May 2003 4:19 pm, Reinhard Amersberger wrote:
> Hi Jason,
>
> you can call me penetrant if you want ;-)) ...... but you still haven't
> give your opinion about how do you plan to realize transition stuff?

That's because I have not really got a plan at this stage :-) All I have is a 
feature list of what I want to be possible :

* It should be possible to perform a transition based upon three or more clips 
on the timeline. I don't think there is such a thing as a simple example :-) 
but here is one : a specialised crossfade in which one image crossfades to 
another on a pixel-by-pixel basis, dictated by the brightness of the pixel in 
a third movie.

* Each clip involved in a transition may itself be a compound clip of 
transitions.For example, it should be possible to have clip A crossfading 
into clip B, and then have that sequence wipe into clip C. Of most 
importance, it should be possible to do this without rendering down the Clip 
A -> clip B first.

* The case of transitioning from one clip to another should be *EXTREMELY 
SIMPLE* :-)



I have before wished that when I was using Adobe Premier that it was capable 
of doing the first two points, and the third point is enforced by the desire 
for Kdenlive to be 'user friendly' ;-)

The aim is that simple stuff should be easy and hard stuff should be possible.


Now, current thoughts going through my head on how to deal with this : 
firstly, the possible solutions for the simple case of one clip transitioning 
into another :

1. We have two separate tracks for clips, and a transition track between them. 
Drag a clip to each track, slightly overlapping, and drag a "transition clip" 
to the transition track.

Advantages : Quite simple.
Disadvantages : Doesn't take into account transitions with more than two 
clips.

2. We use a single track. Drag one clip on to it, drag another clip on and 
place so that they slightly overlap. The overlapping area automatically turns 
into a "transition area", which can then be selected to adjust it's 
properties.

Advantages : Simple and efficient. There is no need for a third operation to 
create a transition, you simply need to overlap to clips on a track. There is 
no confusion over which track is currently "live" as can happen in AB editing 
(at least in Premier), since everything occurs on a single track.

Disadvantages : When two clips overlap completely, how do you allow selection 
of the two clips again? We have compressed our timeline from two tracks to 
one - is that a good thing, or more confusing?


There is a third solution which I am thinking of, sort of a cross between the 
above two ideas, in which a transition would be 'drawn' across multiple 
tracks (I envisage it as a translucent blue rectangle spanning multuiple 
clips). This would have the advantage of allowing the transition to touch 
multiple tracks, but might be complicated to use, I am not sure yet.

So as you can see, my thoughts are still pretty fuzzy on the issue :=)

Cheers,
Jason

-- 
Jason Wood
Homepage : www.uchian.pwp.blueyonder.co.uk