frames, keyframes and audio sync

[Chillheimer]

ahoy!

best to start a new topic for this one..

so I'm working on this 13:30 minute long zoom in 7680*4320.
and this time I mean it. I want it to be perfect. and in sync with the music that I produced.


so mr.chaos that I am actually made an excel-sheet. now that's spooky. at least for me..  
kfb-nr --- fps/speed --- total framcount --- absolute time --- events in music --- events in zoom(tied to kfb nr)
and it seems to work. in theory.

and I rendered it in 640*480 for "fast preview editing".

now here comes the big BUT:
it doesn't work. my movie has 30fps.
I start at kfb 0 with a movie maker speed of 47 frames per second, constant.
and want to reach frame number 2585 at kfb nr 55.
so 2585/47=55.    (=1:28minutes where the music changes drastically, so I start some extreme cycling at kfb nr 55)
but the cycling happens much earlier at 1:25min. so its 3*47=141 frames too early.

and I can't explain that.

I've tried around, tested and tested. but this is what keeps happening.
and I don't want to do chaos excel calculations that aren't worth the effort.

Soooo, am I doing sth wrong, or is there some bug here?!




ps: kalle, please consider renaming "frame number" (meaning the kfb-number in reverse order) in the movie maker to something more unique. I'd say keyframe, but that officially is something else. how about kfb-nr? or zoom nr?
dunno, but this mixing up of the term "frame" makes it unnecessary hard to communicate imho..

[TheRedshiftRider]

I have tried this before but it only works if there are no changes in zooming speed. I haven't figured out how to do it with speed changes.

[Kalles Fraktaler]

I am sorry but this is not fully worked through.

The speed transitions are smooth and exponentially.
If you start with 20 frames per key frame and on key frame 5 put 40, the transision will take place in key frame 4 and the number of movie frames for this key frame will be something in between 20 and 40 so that the speed is 40 at key frame 5.
I actually don't know how many there will be. Maybe i should at least measure that.

[Chillheimer]

hmm..
what about the following idea:
instead of making a seperate field for speed, rotation, colour cycle&division, how about making one "matrix" that has all values in on field?
... hm i'll try to put that into a picture rather than describing it, see attached..

of course I'm no programmer and don't know how to implement this, but maybe it's relatively easy.
after all this does the very same thing as the programm does now
the fields are just positioned differently and some values are added automatically based upon the last row.

and the time is calculated based on fps*(sum of frames per kfb) /60 -->time in seconds.  with your exponential smoothing thing..
as soon as this formula works, you could turn it around and and the formula could set the speed when the user enters a desired time and kfb. we could then enter "i want to reach kfb nr10 at 32 seconds." and the formula automatically enters the speed.

[Kalles Fraktaler]

I think it is an excellent idea to let a time stamp on key frame number decide the speed of a movie.
I will have a look whenever I get the time.
I am currently comparing mouse scroll zooming with fx and trying to get kf work similarly:)