Subject: Re: Trembleing Images
From: RICK CATIZONE <[email-masked]>
To: Multiple recipients of list <[email-masked]>
Date: Wed, 20 Dec 1995 22:40:11 -0500

On Wed, 20 Dec 1995, Thomas Desmond wrote:

> The very last moment of my latest flying logo-type animation that was 
> recorded to a PAR seems to tremble, or "jiggle", when played back 
> from the HD on the composite monitor.  This animation was made by 
> compositing a foreground and a background with an alpha sequence 
> in between, but I don't know if this has anything to do with the jiggles 
> that I see.  
> 
> This tremble looks a lot like what one sees on a composite monitor when a 
> field rendered frame of a fast-moving object is first rendered.  
> 
> In case amnyone is wondering, both image sequences and the alpha sequence 
> too were rendered with field rendering activated, although the background 
> was rendered without antialiasing while the alpha and foreground seq.s 
> were rendered with it on.  Does it matter for compositing?
> Has anyone seen anything like this?
> 
Assuming that you have optimized your drive and recorded at proper 
levels, the only thing that I have encountered like what
you describe is siply the fluctuation from two fields with motion.

You might try an experiment. First copy the par file so you stil have 
original protection. Take the copy and import one field into Imagefx and 
save it back out. Cut out the fluctuating frame and relace with 10 frames 
of new still.  There may be a drop in quality because it's one field, but 
take a look.  

The other thing is...Is there motion still going on in the last frame? If 
there is (for instance, a moving object that doesn't leave frame in this 
cut), you need to cut away at the very instant the shot is finished. If 
the PAR holds on that last frame its always going to vibrate.

If you're not editing tape later and need it in one shot, take whatever 
comes next, even if its blank frames to end the thing and add those onto 
the end. I don't think you'll have the problem because you are "playing 
through it".
 
Rick Catizone/ANIVISION