Camera frame rates VS. Project frame rates + Deliverable Framerates

S

Scott Lovejoy

Active member
(This is crossposted on DVInfo with no replies. Also: this may not be the right forum, but it was my best guess. Feel free to move.)
A story followed by some questions:

A fellow filmmaker was complaining the other day about some DVDs he got back from the replicator. He said that they didn't look very good, and that their reasoning was that he had shot 24p (DVX100) and imported the footage into a 30i timeline (using Avid). I don't know if what the replicator is saying is true, but I asked the filmmaker why he didn't use a 24p timeline. He responded by saying that 24p timelines are for if you are going back to film. I didn't press the issue, but think that this is incorrect.

After this I had a conversation with another friend and we discussed how the DVX treats footage in the timeline, but realized we didn't know exactly how all these processes work.

So, questions:

1) Does the DVX-100 actually do 24 progressive frames, or is it 30 that gets pulled down in post?

2) I think he should have used the 24p project and done his pull-down when he was done (if he desired to go to 30). His claim of 24p projects only being used for going back to film is false. The DVX was heralded because of it's ability to shoot the same frame rate as the films we are used to seeing in the cinemas.

3) In the end, if you are delivering on DVD does the frame rate end up being pulled down to 30i? If so, do converters do this while the DVD is encoding or is it done when you create the .avi (or whatever) file that you are submitting to the burning program.


I'm sure there is more, and I'm making this more complicated than it should be, but this is it for now.
 
The filmmaker made the wrong choice by editing 24p footage in a "30i" timeline (I hate that terminology BTW, so I'm going to call it "60i" from here on out).

1) the DVX images 24 progressive frames, but embeds them within a 60i recording. If you use 24pA it will strip out the pulldown and give you true progressive 24fps footage.

2) Agreed that he should have used a 24p timeline. Agreed that his claim of 24p projects being restricted to "going back to film" is completely misinformed.

3) NO. You can render a 24p file out to a DVD, and the DVD player will deal with any pulldown to 60i if it becomes necessary. DVD players were designed from the beginning to support native 24p files. If you render out to a 24p file and play that DVD in a computer, you'll see 24 progressive frames and no pulldown whatsoever, ever. It's a perfect direct simulation of the film frame rate. If you play that DVD in a progressive-scan DVD player onto a 24Hz progressive-capable display (such as a plasma or LCD TV) it will also play direct 24p with no interlacing and no pulldown. If you play it on a CRT TV that requires 60i, the DVD player itself will automatically add pulldown to convert the 24fps footage into a 60i broadcast-compatible stream.

So -- always, always, always edit 24p footage in a 24p timeline and master out to a 24p file. The only time you'd ever want to edit 24p footage in a 60i timeline is if you're also mixing in other footage that happens to already be 60i.
 
Barry_Green said:
3) NO. You can render a 24p file out to a DVD, and the DVD player will deal with any pulldown to 60i if it becomes necessary.
Click to expand...


Is this true for DVCam as well? He's coming into more trouble (to the point where he may have to recapture), so we discussed why he didn't just do a 24p timeline. He stated something along the lines of DVCam being a 30i format, so it didn't make sense to go 24p when it was going to be pulled-down to 30fps to put on the DVCam (one of the most used festival format).
 
Are you saying it's 24p footage that was shot on the DVCAM format?

If so, absolutely and unquestionably, strip out the pulldown and edit 24p.

It's really simple: editing at 24p preserves all your options. Editing as 60i destroys your option for ever making a progressive version.
 
Barry_Green said:
Are you saying it's 24p footage that was shot on the DVCAM format?
Click to expand...

Hey Barry,

Sorry, that wasn't as specific as it should have been.

He shot on a DVX100, and is finishing on DVCam (for festival distribution). How does the DVCam respond to a 24p timeline and how does a deck playing 24p footage react?
 
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