Ghosting When slowing down clips... at DVinfo.net

Alexander Peerman · January 16th, 2009, 09:20 PM

Hey guys. I'm getting the hang of using 25p clips in vegas now... just wondering is there some way to avoid this ghosting i get when i go to slow the clips down... i've split a clip and am holding down control to lengthen it and stretch out the time, but i get a lot of ghosting in the movement...
Any ideas?

Douglas Spotted Eagle · January 17th, 2009, 01:34 AM

25p is almost impossible to get to look good in slow motion. Shooting a high shutterspeed can sorta help, but it's still only 25fps.
One trick that works with some footage types...
Duplicate the track once you've slowed it down.
Zoom in deep,
turn off Quantize to Frames.
Nudge the top track to half a frame diff than the bottom frame.
Reduce opacity on top track to 50%

This is a de- interlacing trick that sometimes works with progressive footage that has high motion. But...that blur you see is motion blur, it's an artifact of 25p, and there is little you can do about it. Shoot highest possible framerates for best slow motion. 60p is the best affordable framerate available right now (assuming you need sustained recording time), or if it's critical, there are cameras like the Phantom available for rent.

Alexander Peerman · January 17th, 2009, 06:42 PM

ahhh ! thank you.

I had a feeling 25p would have a problem with this...
its a shame my ancient DV camera was able to handle it well and now my new state of the art HD cam cant !

Douglas Spotted Eagle · January 17th, 2009, 06:51 PM

That doesn't make sense.
You mean your old DV cam shot 50i, right?
So shoot your HD cam 50i. It'll be the same as your DV cam.
More frames = better slo mo.

Alexander Peerman · January 18th, 2009, 06:05 AM

thanks douglas.
I'm not sure what my dv camera shot at.
I have been shooting at 50i, but converting down to 25p to make editing easier.
I thought 50i meant half frames which were put together as opposed to 50 frames ?

Douglas Spotted Eagle · January 18th, 2009, 11:06 AM

Quote:

Originally Posted by Alexander Peerman

I have been shooting at 50i, but converting down to 25p to make editing easier.
I thought 50i meant half frames which were put together as opposed to 50 frames ?

50 *is* half-frames as opposed to 25 full frames, but it's still twice as much motion information... Try using the original source of 50i for your slowmo using the half-offset trick I mentioned. You'll be pleasantly surprised.

Alexander Peerman · January 19th, 2009, 04:37 AM

ahh i would but i've been having to convert my footage down from a 1080i Mpeg 4 file to a 720p mpeg 2 file to edit it smoothly, maybe i should start converting all my clips to a 1080i mpeg2 file... altho it seems like its gonna take up a lot more space just for the sake of slow motion :(

thanks for all this help by the way !

January 16th, 2009, 09:20 PM	#1
Alexander Peerman New Boot Join Date: Dec 2008 Location: London Posts: 21	Ghosting When slowing down clips... Hey guys. I'm getting the hang of using 25p clips in vegas now... just wondering is there some way to avoid this ghosting i get when i go to slow the clips down... i've split a clip and am holding down control to lengthen it and stretch out the time, but i get a lot of ghosting in the movement... Any ideas?

January 17th, 2009, 01:34 AM	#2
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	25p is almost impossible to get to look good in slow motion. Shooting a high shutterspeed can sorta help, but it's still only 25fps. One trick that works with some footage types... Duplicate the track once you've slowed it down. Zoom in deep, turn off Quantize to Frames. Nudge the top track to half a frame diff than the bottom frame. Reduce opacity on top track to 50% This is a de- interlacing trick that sometimes works with progressive footage that has high motion. But...that blur you see is motion blur, it's an artifact of 25p, and there is little you can do about it. Shoot highest possible framerates for best slow motion. 60p is the best affordable framerate available right now (assuming you need sustained recording time), or if it's critical, there are cameras like the Phantom available for rent. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

January 17th, 2009, 06:51 PM	#4
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	That doesn't make sense. You mean your old DV cam shot 50i, right? So shoot your HD cam 50i. It'll be the same as your DV cam. More frames = better slo mo. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

January 17th, 2009, 06:42 PM	#3
Alexander Peerman New Boot Join Date: Dec 2008 Location: London Posts: 21	ahhh ! thank you. I had a feeling 25p would have a problem with this... its a shame my ancient DV camera was able to handle it well and now my new state of the art HD cam cant !

January 18th, 2009, 06:05 AM	#5
Alexander Peerman New Boot Join Date: Dec 2008 Location: London Posts: 21	thanks douglas. I'm not sure what my dv camera shot at. I have been shooting at 50i, but converting down to 25p to make editing easier. I thought 50i meant half frames which were put together as opposed to 50 frames ?

January 19th, 2009, 04:37 AM	#7
Alexander Peerman New Boot Join Date: Dec 2008 Location: London Posts: 21	ahh i would but i've been having to convert my footage down from a 1080i Mpeg 4 file to a 720p mpeg 2 file to edit it smoothly, maybe i should start converting all my clips to a 1080i mpeg2 file... altho it seems like its gonna take up a lot more space just for the sake of slow motion :( thanks for all this help by the way !