Inconsistent interlacing playback

OK. I'm on the bridge and ready to jump. But I'll throw this out to see if someone can make sense out of it. And then I'll talk myself down. ;0)

I frequently have an issue with motion jitter, like inverted fields interlacing, when playing back video encoded and burned with DVD Studio Pro. Check - actually I've re-encoded the same video through Compressor and it didn't fix the problem. It's inconsistent. But, I've even gotten it with something encoded with Compressor. The last time I fixed it, I went back into FCP and bumped my entire timeline 1 frame later and re-exported (same as source export). My thinking there was, and I know this is superstition, that it was like DVD Studio Pro picking an A frame for pulldown. And of course I know that there is no pull down here. Maybe it's and I frame thing. I don't know. The most recent time it was a 720 x 486 project. Grant it, some of the footage was already downconverted from 720p 23.98. But, when I have the interlacing problem with any given video its across the board including any effects, like lens flare, etc.

What is going on?!! Somebody. The pigeons are fly around my head and I'm getting dizzy.

Cheers!

George P

>The most recent time it was a 720 x 486 project.

DVD is 720x480 for NTSC frame rates.

> like inverted fields interlacing, when playing back video encoded and burned with DVD Studio Pro

DVDSP doesn't do encoding. Well, it can, but usually the encoding is done in Compressor. Do you monitor your work on a HD/SD CRT broadcast monitor?



www.strypesinpost.com

If you are converting 23.98 to 29.97, you are probably experiencing pulldown. In order to create the extra frame, two frames are being blended together to create the needed extra 5th frame for every four frames for video.

Since FCP does not show interlace, you will not see the pull down in edit. However, you should easily see the interlaced frames in Quicktime (or a broadcast monitor/TV)

You can use compressor to remove the pull down on encode (assuming the pull down is consistent throughout the video), although, you will have more control using Cinema Tools.

If your source video is 23.98, stick with it and do not convert to 29.97, as DVDSP will work perfectly with 23.98 video and the DVD will play perfectly in all dvd players.

However, if you have to export to tape for broadcast, I would choose frame doubling instead of pull down. To me it makes for a much smoother/cleaner video and eliminates interlace flicker from two blended frames. If you record a show off TV that was originally shot to film or HD, and watch the recording back frame by frame, you will almost always see frame doubling as the programs are probably shot at 24fps (23.98). i.e. Frame advance will show 1-2-3-4-4-1-2-3-4-4-1-2-3-4-4...... e.g. Star Gate xxx, Star Trek xxx, CSI xxx... etc.

hope this helps

Ta

Thanks
Gary Sumlak
thumbprints Multimedia Inc.
Edmonton, Alberta, Canada
[www.thumbprints.ca]

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