HOW TO: 60i to 60p for slow motion??? at DVinfo.net

Shannon Rawls · January 9th, 2006, 09:33 PM

Ok...Say for instance, I shoot a Canon XL-H1 in 60i mode. Regular ole' run of the mill 60i interlaced HDV footage.

Say for instance, I set the cameras shutter speed to something nice and high... like 1/1000.

OK...now say I want to slow that footage up for some cool slow motion stuff. Well, in Vegas for instance, I know I can either change the percentage(%) of the clip to 50% or so, or alternatively I can use the velocity envelope and slow it down that way.

BUT CHECK THIS OUT.......I have heard that since 60i is a total of 60 interlaced "FIELDS" that I can seperate those fields and convert that footage into 60p (but at 1/2 the resolution)....... is that right?

Please tell me... WHAT it the process to do that? How do I change 29.97 60i footage to 59.98 60p (1/2 res) footage?

- ShannonRawls.com

William Hohauser · January 9th, 2006, 10:10 PM

Interesting thought. Aside from incorporating 60i into a 60p project, why would doing this create any special slow motion? Wait, I take that back as I just remembered that NTSC is 60 fields a sec. Essentially 60p 240 lines res. Some slow motion VTRs of yesteryear would play one field at a time and line double the low res picture. But this was when TV sets barely had a resolution above 300 lines. Interpolated 240p might not look very good these days.

What happens in Vegas if you import 60i into a 60p project?

Graham Hickling · January 10th, 2006, 09:38 AM

As far as I'm aware, if you specify a 50% frame rate in Vegas, as you describe, it will deinterlace the fields into frames just like you want it to!

I dont use Vegas, but it works that way in Premiere and AfterFX, and I've also done it using Virtualdub and via an avisyth script.

Someone else may be able to recommend the best-quality way - AfterFX would probably be high on the list.

Graham Hickling · January 10th, 2006, 09:41 AM

By the way, some guy in the Sony FX1/Z1 forum posted a .wmv music video he did for an indie band a few months ago using exactly this effect ...

Joshua Provost · January 10th, 2006, 09:58 AM

Shannon,

Vegas should do a fine job at 50% exactly. It won't simply field double, it will do some blending/interpolating, so you won't lose a full half of the resolution, but something in between depending on the motion in your footage.

The real way to go is Twixtor/FieldsKit, which will give you a lot more flexibility, and do high quality slow-mo beyond just 50%. It does intelligent motion tracking to interpolate the slow-mos.

Josh

Steven White · January 11th, 2006, 07:28 AM

Hiya Shannon,

If it's actual 60p video you're looking for, to keep that "reality" look and make 60p 1280x720p or SD 60p, the procedure is trivial in After Effects.

- make a 1440x1080 (PA 1.33) composition with a framerate of 59.94
- select your 1080i clip and check that the interpretations rules are "Upper Field First" with "Preserve Edges" checked.
- plop clip in composition... and voila! Every field becomes a frame.

Now when you render the footage you have to render it to a 60p file.

Alternatively, if you want to do slow motion (at say, 23.976 fps):
- change the composition frame rate to 23.976
- use the same interpretation rules as above
- plop clip in composition
- with the clip layer selected, click on the "Layer" drop down menu and select "Time Stretch"
- insert a value of 250% and tada! Beautiful slow motion.

-Steve

Shannon Rawls · January 11th, 2006, 08:31 AM

THANK YOU CHRIS!

That's exactly what I was looking for. The answer is in After Effects, Not Vegas. THANKS BRO!!! I appreciate that.

- ShannonRawls.com

Steven White · January 11th, 2006, 08:41 AM

Hey!

Who's this Chris guy?! ; )

-Steve

January 9th, 2006, 09:33 PM	#1
Shannon Rawls Major Player Join Date: Nov 2003 Location: Los Angeles, California Posts: 853	HOW TO: 60i to 60p for slow motion??? Ok...Say for instance, I shoot a Canon XL-H1 in 60i mode. Regular ole' run of the mill 60i interlaced HDV footage. Say for instance, I set the cameras shutter speed to something nice and high... like 1/1000. OK...now say I want to slow that footage up for some cool slow motion stuff. Well, in Vegas for instance, I know I can either change the percentage(%) of the clip to 50% or so, or alternatively I can use the velocity envelope and slow it down that way. BUT CHECK THIS OUT.......I have heard that since 60i is a total of 60 interlaced "FIELDS" that I can seperate those fields and convert that footage into 60p (but at 1/2 the resolution)....... is that right? Please tell me... WHAT it the process to do that? How do I change 29.97 60i footage to 59.98 60p (1/2 res) footage? - ShannonRawls.com __________________ Shannon W. Rawls ~ Motion Picture Producer & huge advocate of Digital Acquisition.

January 9th, 2006, 10:10 PM	#2
William Hohauser Inner Circle Join Date: Dec 2005 Location: New York City Posts: 2,650	Interesting thought. Aside from incorporating 60i into a 60p project, why would doing this create any special slow motion? Wait, I take that back as I just remembered that NTSC is 60 fields a sec. Essentially 60p 240 lines res. Some slow motion VTRs of yesteryear would play one field at a time and line double the low res picture. But this was when TV sets barely had a resolution above 300 lines. Interpolated 240p might not look very good these days. What happens in Vegas if you import 60i into a 60p project? __________________ William Hohauser - New York City Producer/Edit/Camera/Animation

January 10th, 2006, 09:58 AM	#5
Joshua Provost Major Player Join Date: Sep 2004 Location: Phoenix, AZ Posts: 493	Shannon, Vegas should do a fine job at 50% exactly. It won't simply field double, it will do some blending/interpolating, so you won't lose a full half of the resolution, but something in between depending on the motion in your footage. The real way to go is Twixtor/FieldsKit, which will give you a lot more flexibility, and do high quality slow-mo beyond just 50%. It does intelligent motion tracking to interpolate the slow-mos. Josh __________________ Owner/Operator, 727 Records Co-Founder, Matter of Chance Productions Blogger, Try Avoidance

January 11th, 2006, 08:31 AM	#7
Shannon Rawls Major Player Join Date: Nov 2003 Location: Los Angeles, California Posts: 853	THANK YOU CHRIS! That's exactly what I was looking for. The answer is in After Effects, Not Vegas. THANKS BRO!!! I appreciate that. - ShannonRawls.com __________________ Shannon W. Rawls ~ Motion Picture Producer & huge advocate of Digital Acquisition.

January 10th, 2006, 09:38 AM	#3
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	As far as I'm aware, if you specify a 50% frame rate in Vegas, as you describe, it will deinterlace the fields into frames just like you want it to! I dont use Vegas, but it works that way in Premiere and AfterFX, and I've also done it using Virtualdub and via an avisyth script. Someone else may be able to recommend the best-quality way - AfterFX would probably be high on the list.

January 10th, 2006, 09:41 AM	#4
Graham Hickling Trustee Join Date: May 2004 Location: Knoxville, Tennessee Posts: 1,669	By the way, some guy in the Sony FX1/Z1 forum posted a .wmv music video he did for an indie band a few months ago using exactly this effect ...

January 11th, 2006, 07:28 AM	#6
Steven White Major Player Join Date: Nov 2004 Location: Canada Posts: 547	Hiya Shannon, If it's actual 60p video you're looking for, to keep that "reality" look and make 60p 1280x720p or SD 60p, the procedure is trivial in After Effects. - make a 1440x1080 (PA 1.33) composition with a framerate of 59.94 - select your 1080i clip and check that the interpretations rules are "Upper Field First" with "Preserve Edges" checked. - plop clip in composition... and voila! Every field becomes a frame. Now when you render the footage you have to render it to a 60p file. Alternatively, if you want to do slow motion (at say, 23.976 fps): - change the composition frame rate to 23.976 - use the same interpretation rules as above - plop clip in composition - with the clip layer selected, click on the "Layer" drop down menu and select "Time Stretch" - insert a value of 250% and tada! Beautiful slow motion. -Steve

January 11th, 2006, 08:41 AM	#8
Steven White Major Player Join Date: Nov 2004 Location: Canada Posts: 547	Hey! Who's this Chris guy?! ; ) -Steve