[Kdenlive-devel] Keyframes feature

[Dan Dennedy]

On Tue, Oct 28, 2008 at 11:10 AM, Jean-Michel Pouré <jm at poure.com> wrote:
> On Tue, 2008-10-28 at 10:53 -0700, Dan Dennedy wrote:
>> I plan to add more interpolation capabilities at the framework level
>> similar to the way mlt_geometry works today. Therefore, I suggest
>> using a single property with a value syntax following:
>> [frame=]N[;[frame=N]]*. When "frame" = -1, then it means the "end."
>> (-2 means second last frame and so on.) You can actually use
>> mlt_geometry for this now as it actually a fairly generic thing that
>> contains and interpolates up to five floats per key frame allowing all
>> sorts of characters (except '=') as delimiter. (See man strtod for the
>> rules - whatever endptr points to ought to be the delimiter.)
>
> Keyframes are really needed.
> This is my #1 feature, with non-destructive rendering.
>
> Do you think it would be possible to name keyframes, just as they work
> in Final Cut Pro. Each keyframe can have a name, beginning and end.
>
> On each keyframe, you can add one or several effects.

Please do not confuse UI with a library. Keyframes are not something
to which you attach effects at the MLT level. Rather, various
properties are keyframe-able; already there are already several. For
example, mix level for cross fade or the compositing rectangle
position and size. Currently, there is rather specific support for
keyframed and interpolated "geometry-like" property values in MLT
(mlt_geometry). A module can choose to do it is own way for any
property, and some of them do. The point is that I want to make this a
framework facility for any type of mlt_property so that it remains
consistent across modules. As for naming them, well, I don't see a
reasonable way to do that without fucking up the concise syntax that
we have thus far. I suppose an app could figure out a way to do it.
Or, a side-property like foo.key.names=[frame=]Name[;[frame=Name]]*
might work.

-- 
+-DRD-+