Win Premiere 6.5: "Jumpiness" in photos with zoom motion applied

[shooter56]

I am preparing a relatively simple presentation in Premiere 6.5 for Windows that is essentially a slide show of still photos (all 300 dpi .psd files, 720 pixels wide by 525 pixels high). Each photo is up for 6 seconds with a transition between photos. While each photo is on the screen, I have used the Motion option to zoom in slightly (starting at 100%, ending at 115%) for each photo over the course of it's time on screen. Sometimes it's a straight center zoom, sometimes it's a zoom to the right or left or up or down.

The problem is that there is a very slight but noticable vertical "jumpiness" to the photos as the zoom proceeds. The actual motion of the zoom seems consistent enough, but the photos all seem to "jump" very slightly over the course of the zoom. Does anyone know how to solve this problem?

Many thanks in advance for your help.

Scott

 

[Akribie]

There are a number of possible reasons, some of which I mention below.

I'm assuming you want a TV output not for the web. Different answer for non-interlaced output.

Did you render and view on a TV before deciding that the output was not good enough?

If your pictures contain narrow horizontal high-contrast edges/lines, then it is likely that you will see interlacing flicker during zooms. A slight vertical blur (best applied in PhotoShop to save rendering time on the timeline) may reduce the effect.

Are you using a standard project preset for DV? If not, check Lower Field First in the project settings.

Unless you select 'maintain aspect ratio' for your stills, Premiere will distort them to fit the frame.

Why did you size to smaller than the vertical pixel count for PAL of 576 pixels to match the 720 across? Note also that in square pixel space (as in an image from a stills camera), PAL is 768x576. If you only offer 720 across, you will get geometric distortion from square-pixel source material.

Note that using Motion in Premiere 6.5 means that the image is first scaled to frame size, then zoomed. If you have larger images into which you want to zoom, then the transform effect, which can be keyframed, is a better option since it retains full source resolution.

If you use Transform and want to zoom in by 15%, then maybe you'll get better results from starting with images sized to 115% of 768x576 (=approximately 883x662).

 

[shooter56]

Thanks for your very thorough reply, Akribie! This problem of vertical image instability barely shows on the computer screen in Premiere 6.5, but is very visible on a TV (NTSC) - it was only after viewing it on a TV that I discovered the problem.

I tried removing the Motion from the stills and instead applying the Image Pan filter to accomplish the zoom. This completely solved the vertical "jitters" but resulted in a larger problem which you seem to have anticipated above - "interlacing flicker during zooms." Depending on the picture, this is sometimes mild, sometimes extreme. I tried the slight vertical blur you suggested in PhotoShop but especially in the more extreme cases, it didn't solve the problem. Any other suggestions on how to get rid of this "interlacing flicker"? I didn't know the name for it before your post, but you certainly can't miss seeing it!

Again, thanks so much for your reply. Any other suggestions you might have are more than welcomed.

Best,
Scott

 

[Akribie]

Another possible culprit, since you are using NTSC, is color gamut. Areas of a frame blacker than rgb(16,16,16) or whiter than rgb(235,235,235) are liable to generate visual artifacts.

One way to test this hypothesis is to apply the Broadcast Colors effect to a "bad" clip and see if it makes any difference.

If this is the cause, then you have the choice of using the Broadcast Colors filter in Premiere 6.5 or sorting the problem (possibly using Actions) in PhotoShop.

 

[shooter56]

Thanks, Akribie. I'm not really seeing any visual artifacts. It's just that when I use the Motion effect to zoom, I get an image that has a vertical "jitter" as the zoom proceeds. When I use the Image Pan filter to accomplish the zoom, the vertical "jitter" is gone completely. But I get a very pronounced interlacing flicker along certain horizontal lines. That flicker is almost non-existent when I use Motion to get the zoom. It is much more pronounced when I use the Image Pan filter.

I can't believe something as simple as putting stills on a timeline and adding a little zoom has become so complicated. This would seem to be the most basic of projects that almost any video editing program could accomplish. And yet I can't get an acceptable result with Premiere 6.5. I'm looking at a Wednesday deadline for the client and I'm stumped on how to get past this problem.

The input I've received here has been very valuable. If anyone has additional suggestions, I could sure use the help.

Thanks,
Scott

 

[Akribie]

Jittery lines is just one type of visual artifact!

I'll leave you to explore other avenues now.