[Kdenlive-devel] Pan & zoom effect

[Dan Dennedy]

On Thu, May 28, 2009 at 12:00 AM, Mathias Friman
<mathias.friman at knorca.se> wrote:
> Hi there.
>
> As one of the kdenlive users that focus more on the
> functionality of the program rather than the looks
> of its icon, I wonder what the status of the Pan and
> Zoom-effect is? ;)

That status is that it is what it is.

> If i recall correctly it is a matter of implementing
> keyframing in MLT, but the effect is present in my

No, each effect can implement keyframing on its own. There is a plan
to make keyframing more generic and available as a service by the
_framework_ to make it easier to implement a much more comprehensive
keyframing.

> 0.7.3-version, however it seems to be non-functional.

The static effect is functional. I intentionally made it static to
prevent complaints about the quality of animation. To get *smooth* pan
and zoom requires sub-pixel positioning and interpolation. I have
dabbled around with using Qt image library to do this, and I got
smooth zoom working in a crude experiment, but smooth pan required
some scaling tricks with unsatisfactory performance. So, this is still
in a research phase. OTOH, for more aggressive pan operations, you may
find the lack of sub-pixel position acceptable, in which case, I refer
you to a panorama screencast tutorial on kdenlive.org.

There have been simply too much other higher priority things and no
one else working on it. However, it is rather high on my list because
I know how basic and desirable it is to do smooth pan/zoom on photos,
and people including myself have lots of photos. However, bugs and a
better deinterlacer are also high priority with high visibility. Then,
I have my own low-visibility, very high priority task well: reduce the
amount of YUV/RGB conversions.

> Id' be happy to be a test pilot for this and report
> bugs and such if there is a beta or alpha version
> available, but since i'm not much of a developer
> i cannot contribute code in any extent.

Is there an open source app that does this well that I should look at
(besides dvdslideshow, which is a huge wad of unreadable shell script
driving imagemagick)? If you can at least point to the relevant part
of the code in its source repo, then it will be a big help.

-- 
+-DRD-+