DVX100a slow-mo w/ 30P at DVinfo.net

Ian Poirier · July 13th, 2004, 01:44 PM

If I recorded at 30p but pulled it down at 24p could I not attain a nice 20% slow motion effect? Not super slow-mo by any means but it might be a good effect. Anyone try this before?

Boyd Ostroff · July 13th, 2004, 04:09 PM

I don't have any experience with the DVX-100a, however I did a lot of slo-mo on a project last year. I tried using some pseudo-30p which had been deinterlaced with DVFilm Maker. The results were significantly worse than slowing down 60i footage. I think this is due to more temporal information being captured at 60i, even though it's 240 lines per each 1/60 sec.

If you use software that tries to construct new frames in slow-mo (like FCP's frame blending feature), feeding it 30p gives a very choppy effect. You may lose some resolution with 60i but you get smoother motion. If you want the progressive scan effect on the end product then you could use a product like DVFilm AFTER you slow the sequence down. That's what I did and everyone liked the effect.

Why not do a little experiment and see what you think?

Jesse Rosten · July 20th, 2004, 12:12 AM

Hey Ian,

I have tried this technique and it does provide a high-quality, if not subtle, slo-mo effect. I took 30p footage from my DVX, put it in a 24p timeline in Vegas, slowed it down to 80%, and (this is the important part) under the clip's properties clicked the "disable resample" button. If you don't click this button Vegas will try to interpolate extra frames.

The effect is subtle, but it looks pretty good cause you are only using the original frames from the camera (as opposed to using software that constructs new frames)

peace
-jes

Ian Poirier · July 20th, 2004, 12:28 PM

That's what I was hoping to hear!
Thanks, Jes

Barry Green · July 20th, 2004, 03:55 PM

It is indeed perfect slow-mo, it's just not very slow is all. But as Jesse says, you can get frame-for-frame playback, so it's just like as if you'd shot film at 30fps and had it transferred at 24fps.

You can also do a frame-accurate simulation of 12 and 15fps as well on the original DVX100, and the 100A adds some new speeds.

For 12fps, shoot in 24P at 1/24 shutter speed, and play back twice as fast as normal -- it'll be frame-accurate to what film would look like had you shot at 12 fps and transferred at 24. For 15fps, shoot 30P at 1/30th.

Bo Smith · July 21st, 2004, 02:08 AM

Would this also work in final cut?

Barry Green · July 21st, 2004, 10:56 AM

I know little about FCP, but from what I understand you'd need at least FCP 4.5 or FCP HD. FCP 3 and FCE don't support 24P timelines.

Hopefully someone who knows FCP and 24P will write in and tell us if it works, and how to implement it.

Boyd Ostroff · July 21st, 2004, 11:14 AM

I'm still on FCP3 (hey, it ain't broke yet for me ;-) IIRC, there was an application called "Cinema Tools" which let you work with 24p back then. I believe they rolled this into FCP4 when it was released. I don't know if it's still available, or if it would work with FCE however.

I also think that DVFilm Maker does this.

July 13th, 2004, 01:44 PM	#1
Ian Poirier Regular Crew Join Date: May 2003 Location: Rhode Island Posts: 82	DVX100a slow-mo w/ 30P If I recorded at 30p but pulled it down at 24p could I not attain a nice 20% slow motion effect? Not super slow-mo by any means but it might be a good effect. Anyone try this before?

July 21st, 2004, 02:08 AM	#6
Bo Smith Regular Crew Join Date: Aug 2003 Location: Exit28, NY Posts: 64	Would this also work in final cut? __________________ Bo Smith \| Camera Operator / Cinematographer web \| http://BoSmith.tv

July 13th, 2004, 04:09 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I don't have any experience with the DVX-100a, however I did a lot of slo-mo on a project last year. I tried using some pseudo-30p which had been deinterlaced with DVFilm Maker. The results were significantly worse than slowing down 60i footage. I think this is due to more temporal information being captured at 60i, even though it's 240 lines per each 1/60 sec. If you use software that tries to construct new frames in slow-mo (like FCP's frame blending feature), feeding it 30p gives a very choppy effect. You may lose some resolution with 60i but you get smoother motion. If you want the progressive scan effect on the end product then you could use a product like DVFilm AFTER you slow the sequence down. That's what I did and everyone liked the effect. Why not do a little experiment and see what you think?

July 20th, 2004, 12:12 AM	#3
Jesse Rosten Regular Crew Join Date: Mar 2004 Location: Redding, California Posts: 114	Hey Ian, I have tried this technique and it does provide a high-quality, if not subtle, slo-mo effect. I took 30p footage from my DVX, put it in a 24p timeline in Vegas, slowed it down to 80%, and (this is the important part) under the clip's properties clicked the "disable resample" button. If you don't click this button Vegas will try to interpolate extra frames. The effect is subtle, but it looks pretty good cause you are only using the original frames from the camera (as opposed to using software that constructs new frames) peace -jes

July 20th, 2004, 12:28 PM	#4
Ian Poirier Regular Crew Join Date: May 2003 Location: Rhode Island Posts: 82	That's what I was hoping to hear! Thanks, Jes

July 20th, 2004, 03:55 PM	#5
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	It is indeed perfect slow-mo, it's just not very slow is all. But as Jesse says, you can get frame-for-frame playback, so it's just like as if you'd shot film at 30fps and had it transferred at 24fps. You can also do a frame-accurate simulation of 12 and 15fps as well on the original DVX100, and the 100A adds some new speeds. For 12fps, shoot in 24P at 1/24 shutter speed, and play back twice as fast as normal -- it'll be frame-accurate to what film would look like had you shot at 12 fps and transferred at 24. For 15fps, shoot 30P at 1/30th.

July 21st, 2004, 10:56 AM	#7
Barry Green Barry Wan Kenobi Join Date: Jul 2003 Location: North Carolina Posts: 3,863	I know little about FCP, but from what I understand you'd need at least FCP 4.5 or FCP HD. FCP 3 and FCE don't support 24P timelines. Hopefully someone who knows FCP and 24P will write in and tell us if it works, and how to implement it.

July 21st, 2004, 11:14 AM	#8
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	I'm still on FCP3 (hey, it ain't broke yet for me ;-) IIRC, there was an application called "Cinema Tools" which let you work with 24p back then. I believe they rolled this into FCP4 when it was released. I don't know if it's still available, or if it would work with FCE however. I also think that DVFilm Maker does this.