Am 03.03.2012 21:49, schrieb Herman Robak:

> * Figure out what the "default keyframe" is, what's wrong with it, and what 
> it should be changed to.


Hi Herman and the others,

having worked a lot with keyframes, and being sort-of familiar
with the implementation -- I don't think anything is wrong or broken
with the default keyframe. It is just an immediate consequence of
Cinelerra's design regarding keyframes.

The only downside I can see is that this whole concept is rather
low-level and probably you'd need to understand it (technically)
in order to use it effectively. Or, to put it a in a somewhat
provocative manner: it's a "geek feature".


Let's recap. In Cinelerra, keyframes always are effective
"from now on to the future": They set the value at some time point
and this value is in effect for all time points to the right of that
keyframe -- unless there is another keyframe at a later time point
which supersedes the former.

Or, to put it the other way round: for any given point in time,
you'll have to look to the *left* (to earlier times) to determine
the keyframe in effect here. And this keyframe's setting dictates
the automation value in question (fade, pan, camera, projector, mask,
plug-in settings).


Probably you've guessed it by now: when there wasn't any keyframe
defined for that track and that value yet, then the system magically
"invents" a default keyframe sitting at t = 0, and fills in the default
value of that automation setting for that keyframe.


Now, the real complexity gets in with the "generate keyframes when tweaking"
toggle. Yet unfortunately, this toggle is the key to working effectively
with Cinelerra's keyframes. And there is no "best" setting --

When it is ON, then each tweaking of a parameter generates a new keyframe,
or adjusts the keyframe which sits exactly at the current playback position.

When it is OFF, then tweaking of a parameters never generates new keyframes,
but adjusts the *relevant* keyframe for the current position, which is the
next to the left. If there isn't any keyframe, you adjust the default keyframe.


So basically, the default keyframe allows us to have a global setting for the
whole track, and still be able to add keyframing and automation later on
for some segment of the track. And, since we're able to copy / paste keyframes,
we need a means to copy from / to that default setting too. Otherwise, it would
be possible to get into a dead end, and you would be forced to set a keyframe at
t = 0 manually, e.g. after pasting some segment of keyframes from another track.


hope this helps to clarify this insidious feature a bit

Cheers,
Hermann Voßeler



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