Slow motion that uses all the fields?

[MGRip]

Hi,
I wondered how to do a slow motion to an interlaced dv pal footage while using 2 field (in premiere or ae).
beacause in ae it first deinterlaces (interpret footage) and then does a time wrap and in premiere it is the same as ae..

The final video have to be 25..(frame based)

Any solutions?

thanks

[scharfis_brain]

easily achievable with AVISynth and one of its more advanced deinerlacers like TDeint(), SecureDeint(), MvBob() and McBob()

[zambelli]

NTSC DV comes in really handy for stuff like this because you start out at 60 fields/sec and end up with 25 frames/sec - a nice 2.4x slowdown.

[MGRip]

Originally Posted by scharfis_brain

easily achievable with AVISynth and one of its more advanced deinerlacers like TDeint(), SecureDeint(), MvBob() and McBob()

Can you explain how to do it?
I mean how to turn a dv interlaced (25fps) into frame based 50fps. The final result would be a frame based 25fps video that is X2 longer. (with AVISynth)

Thanks

[scharfis_brain]

create an AVISynth script that has these contents:

PHP Code:

import("mvbob.avs")
import("mcbob.avs")
AVISOurce("dv.avi").assumebff()
#bob()
#TDeint(mode=1) #or
#Securebob() #or
#Mvbob() #or
#McBob() # just comment out one of them
assumefps(framerate/2.0) 


this will halve the playback speed. But of course motion isn't fluid anymore.

This can be avoided by using some motion compensated frameijnterpolation techniques:

PHP Code:

import("motionpretectedfps.avs")
import("mcbob.avs")
input=AVISOurce("dv.avi").assumebff()
input.McBob()
Motionprotectedfps(last.framerate()*?, iterate=4) #replace ? by the factor you want to stretch your video
assumefps(input.framerate()*2)
Assumebff().ConverttoYUY2().separatefields().selectevery(4,0,3).weave() # reinterlace 


the result will be an interlaced videowith full fluidity of motion. But be careful. Complicated motion may cause motion artifacts But overall it seems pretty stable.

[MGRip]

Thanks!

I have succeeded to do this, a little different but the same idea using what you suggested.
Here is how I did it:

AVISource("Clip.avi")
separatefields
assumefps(framerate/2.0)

then in virtualdub I resized it back to 720*576 (from 720*288) and saved it back to DV.

Works perfect! ulta smooth X0.5 slow motion without artifacts.

Now I just import the new file into AE or Premiere

[scharfis_brain]

This method is fast, but is by far the W.O.R.S.T method to slow down a video (weird up & down bobbing, stairstepping and loss of resolution).

please use at least:

PHP Code:

AVISOurce("dv.avi").assumebff() 
bob() 
assumefps(framerate/2.0) 


but more advanced deinterlacers will give you a LOT more image detail and stability!

Avoid the method using separatefields() at any cost!

[MGRip]

OK i'll try it now

[MGRip]

Yep, you're right
your way is a little sharper