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Converting 29.97i to 23.98p

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Laura Creecy
Converting 29.97i to 23.98p
on Jul 15, 2010 at 8:50:35 pm

I apologize for this basic question, but its been awhile since I have had to convert frame rate on media and reading all the threads has my head hurting with terminology.

I am working in a 1080p/23.98 timeline because most of the footage is shot on RED. However, we were provided with a 29.97i SD QT file of some B-Roll. I thought I took the proper steps to convert the file for my timeline, but maybe I am not remembering things right.

I deinterlaced in Compressor with frame controls run at 100% of source and got a new file running at 29.97 with no fields. Is this called 30p or 60p?
I ran this new file through reverse telecine in Cinema Tools and have a file now running at 23.98.

The new file is not about 15 min longer then the original file and I can see from the window burn in the original file that frames have been duplicated. Isn't this the opposite of what should happen? Or is this correct. I thought that it would pull frames out so that the timecode burn would be missing frames.

Any insight to my process and a better explanation of adding and removing frames would be very much appreciated.


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Dave LaRonde
Re: Converting 29.97i to 23.98p
on Jul 15, 2010 at 9:49:59 pm

[Laura Creecy] "...a new file running at 29.97 with no fields. Is this called 30p or 60p? "

30p.







[Laura Creecy] "I ran this new file through reverse telecine in Cinema Tools and have a file now running at 23.98. "

Whoops! You should CONFORM the footage to the film frame rate. The motion will be slightly slower. I'm pretty sure that Cinema Tools calls a spade a spade when it comes to frame rates, so don't look for 23.98, but for 23.976.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Laura Creecy
Re: Converting 29.97i to 23.98p
on Jul 15, 2010 at 9:54:47 pm

Oops, I meant conform. (Too many projects going on at once)

Am I correct in that if I did the process correctly, and I framed through, that I would see frames missing in the TC burned into the original footage and that the file would not be longer in time length.



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Dave LaRonde
Re: Converting 29.97i to 23.98p
on Jul 15, 2010 at 10:10:08 pm

[Laura Creecy] "Am I correct in that if I did the process correctly, and I framed through, that I would see frames missing in the TC burned into the original footage and that the file would not be longer in time length. "

You would see ALL time code values burned into the original footage. I bet you're looking at drop frame time code, where there are frame values missing at 1-minute increments. For example, you would go directly from 00:02:59:29 to 00:03:00:02. You're not missing any frames, but the time code jumps to compensate for the 29.97 frame rate.

At 29.97, there are 17,982 video frames in 10 minutes of video. When conformed to 23.976, the duration of the video expands to 12 minutes, 30 seconds.

If you're getting something else, there's something rotten in Denmark.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Dave LaRonde
Re: Converting 29.97i to 23.98p
on Jul 15, 2010 at 11:00:15 pm

When you conform footage, you merely change the frame rate. All the frames of the footage remain.

The change is in the amount of time each frame is displayed. When the footage is conformed to a slower frame rate, each frame is displayed longer, the clip's duration becomes longer and the motion is slower. When the footage is conformed to a faster frame rate, each frame is displayed for a shorter time, the clip's duration decreases and the motion is faster.

Frame rate conversion is different. The duration of the clip remains constant. The speed of the motion remains constant. The number of frames in a second changes.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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John Heagy
Re: Converting 29.97i to 23.98p
on Jul 15, 2010 at 11:09:25 pm

Sounds like you want a 60i to 24p conversion and not a conform. As Dave indicated, a 30 to 24 conform in Cinema Tools will simply alter the playback frame rate to 24 and increase the duration slowing down the footage. If you want to maintain duration and audio sync you need to convert. If this is the case - do not de-interlace - it's easier and smoother to pick 24 frames from 60 fields than it is from 30 frames.

Cinema Tools will not do this conversion. Compressor will but I don't know if it picks frames from fields or does a courser job from de-interlaced frames. I prefer Episode, as Compressor's frame controls require a degree in voodoo to make sense of. Another option is ReVision's Twixtor and FieldKit plug-ins.

In sort, you will end up with frames missing not repeated or maintained.

John Heagy


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Laura Creecy
Re: Converting 29.97i to 23.98p
on Aug 11, 2010 at 7:12:21 pm

Right. I want pull down correct?

I will look at those other software, but isnt there an easier way to do this in FCP and compressor?

The offline files were just given to us on a DVD that was ripped to 29.97 DV-NTSC, but the online files are going to be provided on digibeta. I think with our capture card we can introduce the pulldown, but one set of the the offline was conformed (slowed) not converted (pulldown).


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Joseph Hung
Re: Converting 29.97i to 23.98p
on May 13, 2011 at 4:00:39 am

I know this is rather late, but for posterity purposes...

http://philipbloom.net/2009/05/30/how-to-convert-canon-5dmk2-footage-from-3...

works flawlessly. An extra step of transcode, but Apple ProRes can handle it.

Mac 2.66 GHz Quad Intel Xeon
OSX 10.6.4
FCP 7.0.2
AE CS4
Quicktime Pro 7.6.4
8GB RAM
ProAvio 8TB RAID 5
Blackmagic Intensity Pro
ATI Radeon X1900
RocketRAID 4322
Panasonic Lumix GH1, Panasonic HVX200A, Panasonic DVX100A, Canon 5DMKII, 7D


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