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final render settings: field render or not
I have a green screen composite project. Using miniDV I shoot the host talking in front of the green screen. In AE7, I’m keying out the green and I have a tone of graphics going on behind him. I’ve rendered out as an 8-bit uncompressed file. Playback is at a church, through a program called ProViz (or something like that). Basically, it’s file driven playback so the 8-bit uncompressed graphics and the key look great.
But there’s one problem. The motion of the host seems a little weird. Sort of like a stuttering effect when they move their hands and stuff. Sort of like when you watch 23.98 footage without the pulldown removed.
Should I be rendering interlaced, with lower field first? Or should I leave that set to NONE, the default setting?
-trevor ward
Red Eye Film Co.
http://www.redeyevideoproductions.com
orlando, fl -
6 Replies
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it’s usually a matter of taste, but since you feel that the movement seems a little jerky, you might try interlacing, it should help smooth the motion out if the display draws the image with fields. if the display is progressive it will have less of an effect.
note that you renders will be 2x as long (there will be 2x the calculations for animated material).
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
Maybe uncompressed 8-bit is too much data to push through the hard drive?
Did you try Photo-JPEG?BTW, if it plays on a computer (not a TV), don’t go interlaced.
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Yeah, it’s playing through a computer, through a switcher, to a projector on a massive screen. And I guess it IS possible that the system can’t handle the bandwidth of8-bit uncompressed. Although it’s a brand new MacPro tower.
-trevor ward
Red Eye Film Co.
http://www.redeyevideoproductions.com
orlando, fl -
… also the projector/monitor would need to have a high refresh rate, if you are seeing tearing on the video.
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the data rate of the sata bus and hard drive in a new macpro should be able to handle a single stream of uncompressed sd, unless it is extremely full. however, it wouldn’t hurt to kickout a compressed render as steve mentioned, just to rule data rate issues out.
you may want to find out if the projection system uses fields to project the video image (and which field first). if i doesn’t then rendering in fields won’t help much and may make it look worse.
if it project a progressive image, you could try enabling frame blending for the host footage that the keying effect was placed on to see if helps smooth things out some. enabling frame blending will use the data from the other field of the original footage and blend it with the first field data, which can help sometimes. other option would be plugins like reel smart motion blur to add motion blur to the footage to smooth things out. you can try timewarp, with the speed set to 100 but enable the motion blur setting in the effect to generate a ‘poor man’s’ version of reel smart motion blur.
to get the best results using either effect, you will want to work with the keyed footage in a 59.94 fps comp so you can use the field data from the second set of fields. and it would probably be best to prerender that to use in your final composite at 29.97 fps. and again enabling frame blending for that 59.94 footage in the 29.97 comp may further smooth things out.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
I’d say it could be a number of things. First off, if it plays fine on the computer screen but not your video output, then my guess would be it’s a field order problem.
Video out on your mac should automatically take care of that issue if you don’t render fields (progressive), since you would simply get the same frame twice for each scan giving you an effective 30fps instead of 60 fields, and the video device would deal with that.
I’ve had video that started out looking perfect go all steppy on me on output though because the field order was reversed to the that of the output device, which basically makes time go backwards within the two fields, but not the frames.. not pleasant at all… try a copy with lower field first, and another with upper field first. (and have a progressive version handy too, if the project doesn’t required days and days to render 😛 )
Failing all the above, your video output device might be scaling the video to the screen rather than full overscan field-to-field matching, which could bugger up the interlace altogether, in which case I would say just go progressive and leave it at that (OR look for a feature to enable overscan).
Honestly, since I got my HV30s, I shoot everything in 30p and leave interlacing behind. It all displays nicely on any set I’ve tried and just looks cleaner somehow.. Interlacing is a legacy hold off from the old days when displays couldn’t refresh fast enough to hold an image for a whole frame and is (hopefully sooner than later) going to become a thing of the past anyways.
I hope I’ve interpreted your situation properly and my comments are of some use…
Brian
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