Jittery Top On Still Pictures

tserface wrote on 11/15/2002, 2:38 PM
It seems like every time I create a photo montage thing the very top of the output won't stay still. All I am doing is placing PNG files on the time line, doing a slight pan in for some motion, and then crossfades between pictures. I've tried rendering with odd first, even first, progressive, reduce interlace flicker, best, good, all sorts of different settings, but I always get the same result. I also put on the Broadcast Color filter with the clamp setting. It does the jitter thing on several different televisions so I know it's not just the playback device. Does anyone know what cause this sort of thing? It doesn't seem to do it on every picture either so there must be a catalyst, but it is annoying enough when it happens (lots of the time).

Thanks,

Tom

Comments

HeeHee wrote on 11/15/2002, 5:03 PM
Do you have "Quantize to Frames" enabled? This is useful for stills and slow motion.
tserface wrote on 11/15/2002, 6:30 PM
No I don't. I'll give that a try tonight. Thanks.

Tom
tserface wrote on 11/15/2002, 6:47 PM
That didn't make any difference. :( It was already on.
JJKizak wrote on 11/15/2002, 7:06 PM
I have noticed that going to a constant bit rate instead of variable
bit rate removes almost all of the still picture hash coupled with
interlace flicker and resample. It increases the data total by about
40% however. The 72 dpi pictures look fine and most of the 720 dpi
pictures resampled to 480 x 720 blink profusely until rendered. These
are all jpg and not png. This is with the default 5 second length set
in. Also multiple pan/crop with cross fades. My Sony digital cd-r
mavica still camera creates confusion on lots of horizontal lines such
as exterior home siding which the CBR removes completely. Not sure what
the best dpi to use for pan/crop and minimum noise/focus on zoom. I do
know if the preview window is not set to the timeline size the results
are not good. The problem (my theory) is if your picture is 620 x 480
and you put it on the timeline where everything is 720 x 480 does Vegas
try do do a bit of resizeing causing the flickering? I don't know. I am
still very amateur about Vegas learning something new every day.


James J. Kizak
Tyler.Durden wrote on 11/17/2002, 7:30 AM
Hi James,

>>>>>>(my theory) is if your picture is 620 x 480
and you put it on the timeline where everything is 720 x 480 does Vegas
try do do a bit of resizeing causing the flickering? <<<<<<

Vegas will take a 620x480 image and fit it to the frame based on its largest dimension relative to the aspect of the project.

So, If your project is 720x480, Vegas will fit the image to the 480 value, and the sides will show whatever background is behind the image, 'cause 680 is not wide enough to fill the frame. The image is not resized in this case, because the 480 dimension fits properly.

Conversely, if your image were 800x480 (wider aspect), Vegas would re-size the image so the 800 dimension would fit, and the top and bottom edges would show background beyond... you would need to deal with scaling artifacts there, or maintain source aspect and crop to the 480 dimension, cutting off the sides.


That's my grey-matter dropout on how it works...


HTH, MPH

Tips:
http://www.martyhedler.com/homepage/Vegas_Tutorials.html
tserface wrote on 11/17/2002, 9:02 AM
You can, of course, turn that off in Pan/Crop, but I didn't and my pictures are 655x480 which is a good size, I think, based on the pixel size for NTSC on the output.

I tried lots of things yesterday, switching just about every setting, but none of them seem to make any difference. I'm guessing that the DV encoder just doesn't like stills much as I don't have this problem with ULead's cheaper product. I also don't have the problem with motion video that started off as DV. I even ran a low-pass (blur) filter on the pictures and used PhotoImpact to restrict the colors to NTSC safe in case that was causing something. I know it's not the VCR because it records other things just fine. It only happens on still pictures when I am panning in slowly and it only started happening with VV version 3 (version 2 didn't have this problem) so something must have changed in the new version.

:(

Tom
JJKizak wrote on 11/17/2002, 9:06 AM
Thanks Martyh:
I am still wondering why most of the still pictures at 720 dpi .jpg (resampled
from 1900+ down to 720 x 480) pick up the jitter on the timeline rather than
the 72 dpi .jpg still pictures which are rock solid. Duration does not seem to
change much but I was thinking maybe Photopaint was doing something on the
resample process.

James J. Kizak

Tyler.Durden wrote on 11/17/2002, 9:18 AM
Hi All,

You might try the "reduce interlace flicker" checkbox in the event properties... and try render at Best quality when doing still montages.

You will get scaling in Vegas if you resize large images to 720x480... the SoFo suggested size is 655x480 to resolve DV pixel issues.

With stills, you may get single-pixel lines which will twitter, the above switch should resolve this...


HTH, MPH

Tips:
http://www.martyhedler.com/homepage/Vegas_Tutorials.html
rburson wrote on 11/19/2002, 8:56 PM
Tom,
make sure that you are not setting a motion blur type in the rendering dialog - set it to none. that would give you that flickery effect with image motion, because of the low number of interpolated positions used when using keyframes to do this.
rob.
plasmavideo wrote on 11/20/2002, 5:12 PM
OK, so if you are going to start out with a LARGE image in order to have more detail when you zoom in, is there a recommended size/dpi to start with to minimize artifacts?

For instance, if you are going to end up zooming in 2X or 3X (or greater) what size image is best to start with - a multiple of 655 x 480?

I've done some very nice zooms on large images in VV with odd sized ratios and large file sizes and I guess I lucked out, but some had a swirly, frame interpolation problem (I assume) that didn't show up on others.

Tom