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Old February 16th, 2009, 04:39 PM   #1
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Ghosting, is this normal motion blur?

Hi,

Ok this is shot 50fps and sped up to 200% on vegas timeline (this I did cause theres some slow motion playback at the end where the footage is slowed down to 50fps).

But, Im seeing this weird ghosting or motion blur. It looks pretty liek pretty normal motion blur that you get when you pan, just on a heavy side. Funny thing however is that when I have vegas preview set to preview auto its not there, good or higher its there and of course when I render.

If I go through the video frame by frame with preview set to preview auto that "double image" or "ghosting" is not there. If I go frame by frame in good or higher quality its there.

Im guessing its just normal motion blur but just wanted to double check!

Sami
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Old February 16th, 2009, 04:41 PM   #2
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Was this shot interlaced?
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Old February 16th, 2009, 05:30 PM   #3
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I shot it 720/25 overcranked to 50fps.

OK! I found out whats causing it! Its the fact that its shot 50fps and then sped up with a velocity envelope to 200% (making it 25fps). Thats causing it.

How do I make a 50fps into 25fps so that this doesnt happen? Why does it happen? Is it possible that vegas handles all the velocity changes as interlaced?

Sami
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Old February 16th, 2009, 05:49 PM   #4
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I tried setting the project settings to different frame rates and all yield slightly different looking results, interesting is that when I put 20 or 22fps as project speed it looks fantastic, no ghosting whatsoever.
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Old February 16th, 2009, 07:00 PM   #5
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This is something of an educated guess, but is probably worth a try.

These don't exactly look like interlacing artifacts. They do look like field order error artifacts. FO is the term for which of the two fields marks the start of a frame. In DV, lower field first; in HDV, upper field first. (also known as field dominance.)

To narrow in on this (if it is indeed the source of the error):
*Match project properties to media properties. Notice the "Field Order" pull down on the video tab of project properties. If you have DV on the timeline, set to "lower". HDV, set to "upper". If your source video is not raw from the camera it is possible that any processing has upset the field order. Experiment... if the field order of the source footage is incorrectly flagged it can also be changed through clip properties (on the timeline) or media properties (in project media).

*Make sure "quantize to frames" is on when you drop video on the timeline and cut. Otherwise, you might cut on a field instead of a frame...

*If you have regular-speed video in the project as well, and are experimenting with the above, fixing the field order issues for your 200% footage might break it for your regular clips. In which case, you'll have to render just your fast-motion footage and then bring it back into the project. If you go this route, you might also try a 50fps project to do your intermediate fast-mo render.

This is harder to write about than to do - good luck, I hope this helps you fix it.
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Old February 16th, 2009, 08:17 PM   #6
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Hi Seth

Thank you very much for the advice. My footage is from an EX1 camera shot at 720p at 25fps overcranked at 50fps. No intermediate file, mp4 file rewrapped to mxf and dropped on the vegas 8.0c timeline.

Just taking a quick look and I think at least one of the culprits is that when I set the velocity envelope to 200% (with my mouse) and although it reads 200% when I went to the key frame and chose "set to" it suddenly read 199%. Setting it to 200% by typing in the numbers AND choosing 50fps as the project fps I dont see the artifacts anymore on the timeline.

Problem now is that trying to render it to any 25fps file the artifacts appear again.

Oh boy, this might be a tough nut to crack :(

...OK! tried changing media properties from the timeline and checked "disable resample" AND SUCCESS!!!! YES!!! It looks and works perfect!! :D

Oh and also now I can have the project properties at 25fps and it still looks good! :D

HAPPYYYY!!!! thanks everyone! :D
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Old February 17th, 2009, 04:54 PM   #7
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Really proud of the results here :D Thanks to everyone who helped me!! Had A LOT of technical problems and solved them all!!

This is a password protected video on Vimeo
pass: fonalpromo
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