[CinCV TNG] cinelerra-gg Speed Fade Automation oddity

Good Guy good1.2guy at gmail.com
Fri Sep 8 01:20:40 CEST 2017


>
> Double clicking is good, but to be sure to have the speed handles at
> the same speed ("height") on every track I had to:
>

Good observation!  I had not noticed that.

As I was trying to reproduce the problem, I picked media that was over 3hrs
long.
This leads to the following horrible discovery.  There is a design bug in
the speed auto.

The problem occurs when you pick an speed auto position that is far from
the beginning.
Since the video was 3hrs, i casually picked a point near 1.5hrs, near the
middle of the
video edit.  This causes the code in amodule.C to calculate the exact
sample time
for 1.5hrs in by integrating time, that is to say adding up all of the
discrete sample times,
up to the speed auto position.  This is:
48000samples/sec*3600sec/hr*1.5hrs = 259200000.
To get the time derivative, it has to evaluate the speed auto at every
instance..
that takes forever... maybe even longer.

The  upshot of all of this blather is that the speed auto can only be used
effectively
on short edits...  possibly only a few minutes of media.

It may be possible to upgrade the program to calculate the speed
positions using direct math forms, but that is complicated.  Another plan
is to not
recalculate the time integral if play is continuous, but that has problems
too.

Thank you for such insight on the speed auto update parameters.  This is
obviously
not well tested.  You are probably the first one to put it to use on real
cases.  I have
tried it in the past, but only on small test cases that seemed to work just
fine.

gg/phylliis

PS: Phyllis says she will try to put some documentation updates into
features5 to
describe the problems and recommendations.




On Thu, Sep 7, 2017 at 3:32 PM, Frederic Roenitz <ml1 at aimvis.de> wrote:

> > What am I doing wrong?
>
> ... the trick was to be 'ultra careful' instead of only 'very
> careful'.
>
> I just rechecked what I rererererechecked before writing my previous
> mail.
>
> Double clicking is good, but to be sure to have the speed handles at
> the same speed ("height") on every track I had to:
>
> - double click the video handle (not one of the audio handles: video
>   speed handles can only be placed between two frames, whereas audio
>   speed handles can be placed 'everywhere' (probably on every audio
>   sample)).
>
> - hold the mouse button
>
>  - move the handles to the upper boundary
>  - move the handles to the lower boundary
>
>  or respectively
>
>  - move the handles to the lower boundary
>  - move the handles to the upper boundary
>
> - place the handles
>
> - release the mouse button
>
>
> This is maybe something for Feature5.
>
>
> By the way: Alt- and Shift-keys are also helpful while dragging a
> handle.
>
>
> Kind greetings
>
> Frederic
> _______________________________________________
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> Cinelerra at lists.cinelerra-cv.org
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>
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