Strobe Effect!

lnetzel wrote on 8/6/2003, 2:16 AM
I have created a script that will create sort of like a strobe Effect by splitting events and then muting or deleteing everyother event... but it does'nt really look liek a strobe effect anyway, it's mort like blinking... so I wonder. Is a Strobe Light ON longer than it's OFF? Cause now I have the Effect muting and showing events the same amouth of frames...

Comments

TorS wrote on 8/6/2003, 3:01 AM
Why don't you just create a black solid colour event on the track above and trim it/repeat it to the desired effect? You could make it semitransparent if it turns out too dramatic.
About the strobe length on/off I guess there are thousand answers, all of them correct.
Tor
lnetzel wrote on 8/6/2003, 3:46 AM
Yeah I fixed it that way instead... so I guess now I have a Script that will create ficker tat I can't use reallly... :) Thanx!
Grazie wrote on 8/6/2003, 5:13 AM
Flicker! Oh yes you can! Get a real old movie look with this. Use the flicker to create bump map changes for spectacular colour masks. Slllooooow done the flicker and you've got an excellent dramatic "flash through" in black . . . . your time hasn't been wasted . .

Grazie
statas wrote on 8/6/2003, 7:32 AM
i create a nice random strobe effect by cutting and pasting blocks of edits on top of each other several times. after six or seven times, it takes on a life of its own. very effective random distorted strobe.
lnetzel wrote on 8/6/2003, 8:07 AM
How do you mean, this sounds interesting! Blocks of edits? On top of each other? You mean by masking?
lnetzel wrote on 8/6/2003, 8:08 AM
well.. here's my script then... http://midihead.servehttp.com/
statas wrote on 8/6/2003, 6:27 PM
well you need to have quite a few short clips on the same timeline in a short period of time; 20 - 50 clips in 1 - 3 minutes (although you could tweak the numbers as needed). they could be different clips or one long clip that has been cut into smaller pieces. then you copy a section of the timeline and paste it back on to itself (without or without fades). repeat that process 5 - 10 times until the strobe effect happens. you are essentially layering on the same timeline. the cool thing is that the strobe effect time is totally random, sometimes 1/10 of a second, sometime 1/2 a second. you can then render the entire clip to an avi and then use the segments you like.
lnetzel wrote on 8/7/2003, 12:42 AM
I tried.. do I need to have empty space between the the Clips? I tried chopping up a 1 minute clip and then jsut copy it over itself up to 10 times.. ... but nothing happened.
statas wrote on 8/7/2003, 2:08 AM
you should copy only about a 1/4 of the timeline and then paste it back somewhere else on the timeline, not back on itself exactly. you don't need empty space. one more thing, it would be better to keep a copy of the the original timeline in case you need it. let me know if this works. now i'm curious if other people can do it, and if they like the results.

i posted a sample here - www.fodo.net/video/nanostrobe.rm
lnetzel wrote on 8/7/2003, 2:54 AM
Aha, kind of jumpy flicker feeling.. I like it! I think i cut it a little to short about, 5 frames per clip, but I got the idea and understand what you mean... good idea... since I'm doing background video for Live Performances right now!
statas wrote on 8/7/2003, 3:35 AM
thanks, i'd like to see anything you created with that idea, if use it. i'm also doing background video for live events. email me if you'd like to talk about that - bbcp@fodo.net
Grazie wrote on 8/7/2003, 4:39 AM
See - I said you hadn't wasted your time . .

Good luck,

Grazie
jbrawn wrote on 8/13/2003, 3:52 AM
A strobe light is on for a very short time - usually less than 1/1000 sec. This is how we get those amazingly sharp drop of milk films in extreme slow motion...

Your eye continues to see the extremely short flash for quite a bit longer. Let's call it "persistence of vision". A useful human trait when you are working with Video.

To get a "realistic" strobe effect, I've taken individual frames, repeated them and faded them out over the course of 4-8 frames of timeline. Sometimes I'll make the first frame of each set overly bright.

I'm not sure how to say this clearly, but imagine that you start with frames numbered 1,2,3,4,5,6,7,8,9. After mucking about, you'd have bright1,1,dim1,black, bright5,5,dim5,black, bright9 etc.

It also helps to get a strobe light like click placed on an audio track just at the begining of each frame of new "flash". Most strobe lights have a spring reverb like tail after the inital "pop". Maybe the best way to get it is to record a strobe light's sound with your camcorder, and bring in the audio from that.

You might also put the bright part on only the first field of the bright frame. I personally think it makes the strobe effect look more "real", as though the camera was shooting in a strobed environment. I know that some people prefer the bright frame to include the entire frame.

I'm not aware of a script that does this. It was painful and time consuming when I did it.

I split the video at the strobe frequency (every 4 to 8 frames). Then I set the velocity envelope to zero on each video event. I pulled the fade out over one frame and pulled the right edge of the event over 1 frame. (this gave me one dim frame and one black frame.) Then I added a frame (or field) of semi-transparent white above the first frame of the event (on another video track).

Have fun,

John.
Grazie wrote on 8/13/2003, 4:02 AM
I think Excalibur can insert at frame level?

Grazie
TorS wrote on 8/13/2003, 4:56 AM
John,
Based on your good post I tried this:
Made a solid black on the track above.
Using keyframes I set the first frame to full alpha, the second frame to a 2/3, the third to 1/3 and the fourth to total blackness. And for the fourth I selected "hold" as the keyframe option.
To get the flash I boosted the gamma level of the entire video event.
I then copied the keyframes (Click the first and shiftclick the fourth) and inserted them several times down the line.
I could adjust speed, durations etc to my liking.
Then, and here's the main point: I could render the generated media and simply drag-drop it on any video event later. I'd just have to remember to boost the gamma level.
I think it's a good idea, and you set me on to it.
Tor