[This article was first published in the February, 2006, issue of
Larry's Final Cut Pro Newsletter. Click here to subscribe.]

Here's an interesting problem I ran into recently for a broadcast client. They were doing a lot of chroma-key work, using DVCPro-50 as their source video, and all their keys had a very soft focus.

In looking at the problem, I realized they were the victim of interlacing. The fix was simple, but not intuitive.

Here's the issue. All Standard Definition (SD) video is interlaced for broadcast. And, unless you are specifically shooting DV footage in progressive mode, all DV footage is interlaced as well.

Interlacing means that first all the even lines are displayed on the screen, then all the odd lines. Final Cut hides this from you by displaying all lines at the same time -- which is why, sometimes, it looks like there are thin horizontal lines running out from the edges of moving objects when you view fast-moving images on your computer screen.

However, even though the computer displays video progressively, the interlacing is still there.

The problem my client experienced happened when they repositioned the key source on V2 (the anchor on a blue screen) against a highly animated background on V1. In doing so, they put all the even scan lines on top of the odd scan lines. This created a weird interlacing conflict that caused the image on V2 to get blurry.

The solution was simple. Make sure, when you are positioning your key source on an upper video track, that you only position it in increments of 2 vertical pixels. You can move images horizontally however you wish. But vertical position needs to move by even pixels.

In the Motion tab, there are two data boxes for the Center parameter. The left hand box controls horizontal position and the right hand box controls vertical position.

This tip is from the February, 2006, issue of "Larry's Final Cut Pro Newsletter," a very cool FREE monthly Final Cut Pro newsletter -- subscribe at Larry's web site: www.larryjordan.biz.

Larry Jordan is a post-production consultant and an Apple-Certified Trainer in Digital Media with over 25 years experience as producer, director and editor with network, local and corporate credits. Based in Los Angeles, he's a member of both the Directors Guild of America and the Producers Guild of America.

Any references to trademarks or products are used for editorial purposes only. Text copyright 2006 by Larry Jordan and Associates, Inc.. All rights reserved.

Larry Jordan is a post-production consultant and an Apple-Certified Trainer in Digital Media with over 25 years experience as producer, director and editor with network, local and corporate credits. Based in Los Angeles, he's a member of both the Directors Guild of America and the Producers Guild of America.

The information in this article is believed to be accurate at the time of publication. However, the author assumes no liability in case things go wrong. Please use your best judgment in applying these suggestions.

The opinions expressed in this article are solely those of the author. This newsletter has not been reviewed or sanctioned by Apple or any other third party. All trademarks are the property of their respective owners and are mentioned here for editorial purposes only.

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