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23.98 to 29.97p – Interpolating to 29.97 progressive?
Hi! Quick question for you frame rate guys out there…
This weekend I’m shooting and editing a 1920×1080 project at 23.98fps. End client requests final delivery be at 29.97 or 30 progressive. It is also my understanding that, after delivery, the client may be creating a down-converted SD DVD on THEIR end.
Normally when editing 23.98 for delivery @ 29.97 for broadcast, I’ll edit the entire thing at 23.98, then let Final Cut do its interpolation on a final 23.98 QT in a 29.97i/upper field sequence, and export the final 29.97i QT from there.
But since the client is asking for 29.97p, would anyone forsee any issues doing an “interpolation” from 23.98 to 29.97p? Obviously every 4th progressive frame would be doubled instead of being broken up into fields, but is that, on a technical level, “taboo?” Would there be any later issues if they did a software-based downconvert to SD lower field for DVD purposes?
Any advice would be appreciated.
Thanks in advance.
-Aj
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5 Replies
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Picture will look smoother if you add a proper pull-down, but no taboo for repeating frames or interpolating full frames.
[Aj Koch] ” Would there be any later issues if they did a software-based downconvert to SD lower field for DVD purposes?”
Why don’t just make a 23,98fps DVD?
The player will add the pull down on playing.BTW, if you make it 29,97fps, no need to make it LOWER FIRST.
MPEG-2 DVD compliant can be Upper or Lower first.
If your source is Upper first keep it like that. No need for shifting fields.
rafael -
Awesome, good info to know! Thanks Rafael!
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Shooting 30P was discussed, but the client prefers the look of 23.98.
I ran a pulldown test going from 23.98 to 29.97P last night in Final Cut, and seems to work fine, as Rafael suggested. It’s arguably not as smooth as interpolating to 29.97i, but it’s still relatively smooth, and I think the difference is negligible for this project. Final Cut does the pulldown pretty quick, so time spent doing the conversion is minimal.
But I definitely appreciate the opinion!
Thanks,
-Aj
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DVD Players automatically add the proper pulldown.
Pretty much all “Hollywood” DVDs are 23.98, and will play that way via HDMI. The analog outputs will have pulldown added.
Its really a non-issue.
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If we know a project will go to YouTube and DVD and especially a possible PAL delivery we will shoot 23.976 as long as we aren’t mixing our footage with any 29.97 clips.
Also purely animations are sometimes done in 23.976 to reduce frames needed to render.
We use Episode to convert 23.976 to 29.97p as it has great control over the output and we have made great looking pulldowns without hardware.
There are reasons, but if we go to broadcast as a primary delivery I usually recommend 29.97p (30p)
Rich Rubasch
Tilt Media Inc.
Video Production, Post, Studio Sound Stage
Founder/President/Editor/Designer/Animator
https://www.tiltmedia.com
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