Problems with Slow-Motion.

F

fsuplaya2003

New member
Hey,
I recently filmed my brother's wedding and i have been editing it for a few days. However, i am facing a problem i've never encountered before, i don't quite understand it. I shot on the 100b at 30P. I captured the tape via firewire with virtualdub. It looks good. I edited the whole project in Ulead Videostudio 10, which i have had lots of success with in the past. The first odd thing is the amount of interlacing i saw when processing the video. The resulting video is unstable and jittery, alternating normal and blurry is the best way to describe it. The edge of the frame even seems a bit shaky? I have almost every clip at about 70% speed for a slow-motion effect.
In testing, i realized that if i left the speed of the video at 100% or normal, it seemed to be fine. However, it is crucial to use slow-motion. I tried many things. The weird part is i shot some short test footage and captured it in virtualdub, and when i edit these short clips and apply slow-motion, there are no problems. Any suggestions, anybody know of anything like this? I want to get it looking good for them for when they get back from the honeymoon!
I would post a clip, but an image doesn't really show it. PLEASE help.
 
Screen grabs would definitely help. Slow motion is very hard to achieve without artefacts or blurriness and 'jitteryness.' My initial assessment without seeing any of the footage or knowing how you captured the tape and what processes your NLE applied to it would be that its just a result of the 30p setting.

My understanding of 30p is that (and anyone correct me if I'm wrong) your camera doesn't scan the pixels during the exposure as interlaced does. In essence, your camera exposes for a fixed amount of time (user defined) and then switches off the exposure mode and then reads the exposure. Basically this takes a picture and then after the exposure the picture is read and processed resulting in motion artefacting. This motion artefacting helps to create a filmic look by using full frames instead of interlaced frames.

On the flip side, interlaced will expose and scan simultaneously during an exposure and creates two fields which create a full frame however those two fields won't be read at the same exact time which is why interlaced looks bad on progressive monitors such as LCD.

What your problem seems to be is that by slowing down your footage you widened the time-space gap during playback. Think of it as if you shot film at 24fps and then decided to hold on each image during playback 1/3 of the time longer. It would look very stuttered.


long explanation I know but my initial thoughts are that your problems are a result of using progressive scanning and then slowing down the footage. I really have no solution for you because I'm not a big post-production specialist but I'm sure there are filters out there that blur frames to smooth them out. Anyone else have any Post solutions?
 
30p is not a good setting for general slow motion. You'd want to shoot 60i to have the most flexibility for slow motion. The exception to this is when you shoot 30p for use in a 24p timeline. You slow it 80% and it matches frame to frame to 24p.
 
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