Interlacing Issues

AJA Video Systems

Interlacing Issues

Posted by James Orlowski on February 27, 2008 at 8:28 pm

I have a strange issue with interlacing that is puzzling me.

If I render an item in AE, and if that item has consistent, slow, left-to-right or right-to-left motion, the resulting playback of the clip in Premiere on my NTSC monitor is hard to look at, giving an odd “interlacing” effect.

BUT, if I import that AE comp in Premiere and render the SAME area in Premiere, the motion is smooth and easy on the eye.

See for yourself…

I uploaded two identical AJA Quicktime 720×486 clips to the following locations:

https://www.rynopro.com/stuff/InAE.mov
https://www.rynopro.com/stuff/InPremiere.mov

Grab them and place them on an AJA timeline in Premiere, and view them on a standard NTSC monitor.

Look closely at the moving status bar at the bottom on the screen (the bar that simulates fast forwarding and rewinding a DVR cable box). In the AE clip, the motion is interlaced, and hard to watch. But in the Premiere-rendered clip, the motion is smooth. (At least, on my AJA Xena HS system, this is the case. Tell me if it’s different on yours.)

Let me know what you think, and what I might to do remedy my AE renders to avoid this issue.

You may ask, then, what’s the problem if I can just solve this issue by rendering my AE comps in Premiere. But, as you may know, it takes like 5x longer to render a complex comp in Premiere, than just rendering it in AE. So, I’d like to try to make my AE renders look as good on these type of motion clips as they do when rendered in Premiere.

Thanks.

(BTW, those two clips are 107 MB in size each, so I won’t be leaving them on my server very long…. Get them while you can.)

Something else that might be related: while in Premiere, if you pause the AE clip, the resulting freeze-frame is entirely smooth. But if you pause the Premiere-rendered clip, you get the interlacing “jitter” as Premiere quickly flashes back-and-forth between the fields. I suspect this is a result of the issue I’m having above.

—
James Orlowski
RYNO Production, Inc.
http://www.rynoproduction.com
800-860-7966

James Orlowski replied 18 years, 2 months ago 2 Members · 2 Replies
2 Replies

John Baum
February 28, 2008 at 5:40 pm

I’m guessing that the footage from AE was rendered progressively as that is the default behavior. When you render out of AE switch it to field(upper or lower, whatever your Premiere project footage is).
James Orlowski
March 3, 2008 at 2:37 pm

Thanks for the input.

I gave it a shot and rendered a clip with lower field first (before, that setting was OFF in my output settings).

While the resulting clip does playback more “smooth”, it appears to “stutter” when playing back on my Premiere timeline.

I uploaded the clip here:

https://www.rynopro.com/stuff/LFF.mov

See if it plays better on your end.

Thanks.

—
James Orlowski
RYNO Production, Inc.
http://www.rynoproduction.com
800-860-7966

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