Jitter, Jutter

MichaelS wrote on 7/14/2004, 11:00 PM
I have a problem that pops up occasionally that I can neither explain or know the proper term to describe it.

When editing a long form program, usually with lots of edits (mostly simple cuts and dissolves), portions of the final DVD will be jittery. The smoothness of motion will become less fluid. The change looks similar to film, but it's too jittery (is that the word).

I've studied the original clips and can find nothing unusual. The only way that I can find to correct the problem us to mark the first frame of each clip in the trimmer, delete the jittery clip on the timeline, and replace it with a new clip offset by a single frame or more. Once the problem starts on the timeline, it remains until it is discovered and corrected. Repairing the first bad clip has no effect on the following bad clips.

I do know that I can select a portion of a "bad" clip, activate PTT, and receive a "More than 80% must be rendered" warning. I "spot test" the timeline as I edit using PTT to try to catch this issue before I get too far. I've seen the problem on TV, particularly cable, where it looks like an effect.

"Quantize to Frames' is on. This is standard NTSC DV compliant material, straight from camera to Vegas. This is not a "track" effect, since good video is usually resident on the timeline as well.

Can someone name it and tell me how to prevent it.

Comments

TheHappyFriar wrote on 7/15/2004, 6:22 AM
You don't happen to be butting a frame right next to itself, are you? Like this:

Make a cut. Say "oh shoot, the right side of the cut needs to be longer" so you drag the left end out a couple frames, then butt them up.

That could cause what you're seeing.
craftech wrote on 7/15/2004, 6:32 AM
My guess is that it is a combination of gaps and/or small half frames on the timeline. Vegas has always been prone to creating them during the editing process. You have to stretch out the timeline and search for them. In my experience they are more likely to occur when using several video tracks instead of just one.
Also don't overlook the audio track. Sudden unexplained audio flatlines or momentary dropouts often occur randomly in Vegas and can affect the video track with judders, etc. Recapturing can often eliminate them. You can also try rendering to a new track and strectching out the track to look for and fix problems.
In terms of the problem only showing up in a DVD and not in the avi version I would look to settings in Vegas before rendering to Mpeg 2. If that's the case post back.

John
NeilPorter wrote on 7/18/2004, 3:59 AM
I had the following problem with "Judder":

1. It was only on some scenes and not others.
2. No-one anywhere could help me say what the real cause was, though they tried.
3. It took me 3 months to track down the real cause.
4. It took me another 6 months to track it down to being a camera problem.
5. It took another year of fighting Panasonic for a new camera, only to lose on a technicality.
6. Now that I've had a moan, I'll tell you what it was (you may have the same).

My camera randomly splits scenes into smaller parts - a different number of splits and different lengths every time you re-capture the same scene (I re-captured several times while trouble shooting).

It also randomly sets these scenes as either Lower Field First, Upper Field First or None (progressive). You have to reset them all to Lower Field First manually within Vegas. Right-click each separate scene in the media pool and check the field setting - re-set them all to Lower Field First and the judder will disappear.

Mine did!!

If this is your problem and you fix it OK, email me privately on neilporter@fishinternet.com.au and I'll give you a more efficient method of setting all clips to Lower Field First. I haven't tried it out myself yet.

If it's not your problem, then, sorry.

Regards,
Neil Porter
jaegersing wrote on 7/18/2004, 4:57 AM
Hi Neil. That's a very interesting post. Last year, I did a 2 camera shoot, with a Sony VX2000 and a Panasonic NV-DX100 (an old but good 3-CCD camera).

When I captured all the material and assembled the clips in Vegas, I had problems with certain areas coming out juddery after rendering. Eventually, I tracked it down to the fact that all the Panasonic's clips showed as Upper Fiekl in their Properties. Changing all of these to Lower Field fixed the judder.

Richard Hunter
MichaelS wrote on 7/18/2004, 7:46 AM
By golly...I think you've got it!

Now...is there a way to universally set all clips in the media pool or on the time line to lower field first?