Slow Motion "ghosts" from interlacing?

gsstone50 wrote on 2/8/2011, 6:22 AM
When I stretch a segment of video to it's max width to create the slowest motion Vegas will allow, I would expect interpolation to make perfectly smooth motion. What I get is either clearly defined frames spaced out and not interpolated at all; good interpolation at 4 frames per actual frame with clearly defined frames; or interpolation with ghosted interpolation images at 4 frames per actual frame. Even when I get good interpolation with clearly visible frames (the best result I have gotten in previewing) making a movie and storing it to disk never results in that same level of interpolation at any reasonable resolution. Increasing resolution causes the ghost images to display in the final video. Can you help. At a minimum, something must be available that clearly defines the process of making slow motion that is smooth (if possible) but at least free of ghost images.

TIA
Glen Stone

Comments

Chienworks wrote on 2/8/2011, 7:05 AM
Vegas doesn't interpolate at all. All it can do is blend, which is what causes the ghosts. If you want to eliminate the ghosts then turn off resampling. However, what you'll end up with then is frame duplication.
gsstone50 wrote on 2/8/2011, 9:34 AM
That's interesting because I can step thru the original video and identify each frame, then ctrl-stretch the video to produce slow motion. Then stepping thru the resulting video I can see 3 intermediate frames between each "real" frame that I identified in the original video. Sometimes the intermediate frames are clear, individual frames which are just what I want, and sometimes the intermediate frames also contain "ghosted" images of one or more adjacent frames. I do not know how to reliably get rid of the ghosts. If the software does not interpolate, then how am I getting intermediate frames at all. Any ideas?

TIA
Glen
Eugenia wrote on 2/8/2011, 3:30 PM
Select only the video clips in the timeline, right click on them, Switches, Disable Resample.
mattcro wrote on 2/23/2011, 4:48 AM
If anyone's still interested...

As previously said, Vegas doesn't truly interpolate between frames - real motion interpolation requires some serious motion analysis and image manipulation that's beyond Vegas.

If you slow down a video in Vegas to half speed, interlaced footage (eg 60i) will get deinterlaced to half-speed progressive 30p. Any further slow-down will result in blended intermediate frames (resample enabled) or duplicated frames (resample disabled).

If you slow down to 1/4 speed, you should get a clean frame (original first field), followed by a blended frame, then a clean frame (original 2nd field), then a blended frame... and so on.

See Eugenia's blog for some tips on getting the best slow-motion footage: http://eugenia.queru.com/2009/02/09/butter-smooth-slow-motion/