mpeg2 converted to QT & dropped in SD NTSC timeline playback ok until rendered

Strange issue with some clips that were originally downloaded (with the company's permission) from a mediapack-info shows the codec as MPEG2 Muxed and dimensions as 640X480 (I don't know what the original shooting format was-hd possibly).
A while ago a friend who understood all this stuff more than I do converted to a QT and then the sequence was imported into my FCP6 and seemed fine when I dropped into my SD NTSC timeline. So the clips look ok on my MacBook Pro and external LCD monitor and also initially looked ok on my old Sony Trinitron TV that i use as a monitor BUT-- once they are rendered-- they no longer play correctly on the TV monitor--they kind of vibrate and the motion becomes weird. However they still play fine on the LCD screens. Also when I played a dvd with this footage on another TV, same thing--motion is screwed up.
Anybody have an idea what's going on? Only thing I could think of was that the TV's are not HD and maybe if the original footage was, there's some kind of issue. But since the info on the converted clips conforms to the SD NTSC timeline and since FCP6 is supposed to accept all different formats, why would that be?

First , you know how 24p media is supposed to look, right? The motion blur on 24p can be disorienting if you're not used to it. The vibration most likely rules this out, but it doesn't hurt to check.

Could be incorrect field order, or an interlacing issue. Don't trust computer screens for this kind of thing -- computers are blind to issues with interlacing, so you won't see it unless you're using an external monitor. If it looks bad on an external monitor, then that's what it really looks like, and will very likely be like that on DVD.

Try a Shift Fields filter, or Flicker Filter. You should also take one of the clips, open it with FCP, then play it straight from the Viewer into an external monitor. Your original footage may have been converted incorrectly to begin with, in which case you may have to go right back to the source and redo the conversion. Select one of those clips in FCP and press APPLE-9, and list the information there.


www.derekmok.com

thanks for your reply. yes, I know how 24p media looks, but my timeline is 29.97-- was shot with a sony pd170 and the converted clips are also now 29.97--i checked info again. (Of course i don't know what they originally were) Thanks for letting me know that the external monitor is the one to trust. As you suggested I did play from viewer to that monitor and again, it seems ok. I also tried dropping a new clip into the timeline but AFTER the sequence, not into the midst of it--in this case it didn't seem to need to render and therefore looked ok. But when I dropped that same clip into the actual sequence the green bar showed up-- and again looked better before rendering than after. I will attempt the shift fields and flicker--if i can find it. thanks--daria


PS-- I tried the deflicker--it helped a lot athough still not as good as before it renders. De-interlacing made it worse.