[Kdenlive-devel] mlt in kdenlive

Jason Wood jasonwood at blueyonder.co.uk
Tue Oct 18 08:42:19 UTC 2005

On Tuesday 18 October 2005 06:20, Dan Dennedy wrote:
> On Monday 17 October 2005 10:06 am, marco wrote:
> > Hi dan dennedy
> Hi, before going much further... I hope you guys are using MLT from CVS
> HEAD and not an outdated release tarball?!

Yes, we are using MLT from CVS HEAD.

> MLT is stateful and holds an object model of the authored project. I am
> glad we are having this discussion; I wanted to get to it soon. Previously
> , Jason Wood and I had discussed whether it is more beneficial to maintain
> a in-memory document model (DOM) inside the editing tool separate from the
> processing engine. Jason argued for it. However, I think it is
> unnecessarily redundant. MLT has quite a nice document object model and
> manipulation routines.Charlie has been enhancing them as he worked on
> Shotcut and now Jahshaka. This means much of the low level track and
> playlist management is in MLT now.

My concern for using a single Dom model for both MLT and Kdenlive is that I am 
still unsure as to whether the requirements for a Dom in MLT will match 
exactly the requirements for a Dom in Kdenlive.

It has always been my belief that the editor needs to have more semantic 
information about what it's timeline is, and what it is doing compared to 
what the renderer needs to know, and therefore would need to keep a separate 
DOM anyway to store this information.

However, there are points where looking at MLT, it does make sense to me to 
use the model withing MTL - I think that producers should be created for 
clips and kept around, rather than creating/destroying them as we are doing 
at the moment, and that does mean a different take on the dom model, since it 
means that for instance, clip durations could be queried from MLT quickly, 
and there would be no duplication within Kdenlive.

I am open to persuation here; I can see that having the Kdenlive as a 
View/Controller with the Model being MLT would make for a powerful system, so 
long as the Model in MLT can do everything that Kdenlive asks of it (not 
necessarily right now with the code in CVS, but as long as it makes sense for 
the framework to be extended to do whatever Kdenlive asks of it.)


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

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