Mixing 29.97 and 23.97 at DVinfo.net

Jared Gardner · March 19th, 2013, 10:12 AM

I'm shooting footage on a Canon DSLR and it shoots 23.976p native. I've also been given a lot of other footage shot at 29.976 and I'm having a little trouble combining the two. I have a project in Adobe Premiere and I use the DSLR template for 720p 23.976. Upon export the footage looks fine that was shot at 23.976. However the 29.97 footage has a stuttering problem.

There's a bit of choppiness to the 29.97 footage, and to complicate things, it's only SOME of the 29.97 footage. Some of it looks fine, some of it shows choppiness. How could it be only some of the clips?

I discovered that if I go to 'interpret footage' and forced Premiere to recognize the 29.97 footage at 23.976 that it would look fine and fixed it. I've discovered the solution, so I'm posting this to ask about the theory as to why it's working. I thought it'd fix it automatically on export, so I'm guessing that for some reason the interpret footage thing applies a proper pulldown, while a regular export drops frames irregularly, or something, leading to a stuttering effect. Am I right on that?

Jack Zhang · March 19th, 2013, 01:08 PM

Perform a frame rate conversion on the 29.97 footage. 29.97 to 23.976 is better. Use the Video Copilot tutorial on how to do that with After Effects: VIDEO COPILOT | After Effects Tutorials, Plug-ins and Stock Footage for Post Production Professionals

Peter Manojlovic · March 19th, 2013, 06:25 PM

Jared, are you using any third party output devices for playback (ie matrox, blackmagic, aja etc..)?

Jared Gardner · March 20th, 2013, 08:25 AM

I'm using just VLC Media Player.

I just checked again, and really, it's just confusing that some of my clips have the choppy/stutter effect and others are fine. I think it might just be that depending on the clip's motion, it appears more jerky than the next.

So far I've just used the Interpret Footage thing in Premiere and it's working ok. Do I actually need to do a separate frame rate conversion with some other software to do it properly?

Jack Zhang · March 20th, 2013, 10:52 AM

If you want audio to remain in sync, you need to do a frame rate conversion. Interpreting footage actually slows down 29.97 to 23.976, thus making a slow motion effect.

However, if all of your 29.97 footage does not require audio sync, you should be fine. (unless you don't like slow-mo)

Only frame rate convert if there is audio that's supposed to be in sync.

Peter Manojlovic · March 20th, 2013, 07:42 PM

Hey Jared...First of all, you cannot take pure 29.97 footage, and interperate as 23.976, unless it was telecined originaly from 23.976.
Secondly I've never heard of 720 @23.976fps..It's usually a 60P output.

If you make a master sequence of 29.97fps, any footage dropped in should play back fine..

March 19th, 2013, 10:12 AM	#1
Jared Gardner Regular Crew Join Date: Jun 2008 Location: Baton Rouge, LA Posts: 48	Mixing 29.97 and 23.97 I'm shooting footage on a Canon DSLR and it shoots 23.976p native. I've also been given a lot of other footage shot at 29.976 and I'm having a little trouble combining the two. I have a project in Adobe Premiere and I use the DSLR template for 720p 23.976. Upon export the footage looks fine that was shot at 23.976. However the 29.97 footage has a stuttering problem. There's a bit of choppiness to the 29.97 footage, and to complicate things, it's only SOME of the 29.97 footage. Some of it looks fine, some of it shows choppiness. How could it be only some of the clips? I discovered that if I go to 'interpret footage' and forced Premiere to recognize the 29.97 footage at 23.976 that it would look fine and fixed it. I've discovered the solution, so I'm posting this to ask about the theory as to why it's working. I thought it'd fix it automatically on export, so I'm guessing that for some reason the interpret footage thing applies a proper pulldown, while a regular export drops frames irregularly, or something, leading to a stuttering effect. Am I right on that?

March 19th, 2013, 01:08 PM	#2
Jack Zhang Inner Circle Join Date: May 2005 Location: Burnaby, BC, Canada Posts: 3,053	Re: Mixing 29.97 and 23.97 Perform a frame rate conversion on the 29.97 footage. 29.97 to 23.976 is better. Use the Video Copilot tutorial on how to do that with After Effects: VIDEO COPILOT \| After Effects Tutorials, Plug-ins and Stock Footage for Post Production Professionals

March 19th, 2013, 06:25 PM	#3
Peter Manojlovic Major Player Join Date: Jun 2007 Location: Hamilton Ontario Posts: 769	Re: Mixing 29.97 and 23.97 Jared, are you using any third party output devices for playback (ie matrox, blackmagic, aja etc..)?

March 20th, 2013, 08:25 AM	#4
Jared Gardner Regular Crew Join Date: Jun 2008 Location: Baton Rouge, LA Posts: 48	Re: Mixing 29.97 and 23.97 I'm using just VLC Media Player. I just checked again, and really, it's just confusing that some of my clips have the choppy/stutter effect and others are fine. I think it might just be that depending on the clip's motion, it appears more jerky than the next. So far I've just used the Interpret Footage thing in Premiere and it's working ok. Do I actually need to do a separate frame rate conversion with some other software to do it properly?

March 20th, 2013, 10:52 AM	#5
Jack Zhang Inner Circle Join Date: May 2005 Location: Burnaby, BC, Canada Posts: 3,053	Re: Mixing 29.97 and 23.97 If you want audio to remain in sync, you need to do a frame rate conversion. Interpreting footage actually slows down 29.97 to 23.976, thus making a slow motion effect. However, if all of your 29.97 footage does not require audio sync, you should be fine. (unless you don't like slow-mo) Only frame rate convert if there is audio that's supposed to be in sync.

March 20th, 2013, 07:42 PM	#6
Peter Manojlovic Major Player Join Date: Jun 2007 Location: Hamilton Ontario Posts: 769	Re: Mixing 29.97 and 23.97 Hey Jared...First of all, you cannot take pure 29.97 footage, and interperate as 23.976, unless it was telecined originaly from 23.976. Secondly I've never heard of 720 @23.976fps..It's usually a 60P output. If you make a master sequence of 29.97fps, any footage dropped in should play back fine..