Multi frame rate/size/type workflow

[Arnie Schlissel]

Once you confirm the output specs, I think the best thing would be to convert everything to ProRes SQ at 1080 25P. I would use Compressor. For the 23.98 footage, set the bottom pulldown in the frame controls to “make all frames play at 25”. For the 30P you would set it to keep the duration. The 30P will probably show a small amount of ghosting when you’re finished.

Arnie
Post production is not an afterthought!
https://www.arniepix.com/

[Wiremu Harpuka]

Thanks Arnie,
I appreciate your reply-could you explain your choices-just so I can get a clearer idea?

Wiremu

[Arnie Schlissel]

You’ll probably need to refer to the online manual in Compressor’s Help menu, but let me see if I can steer you in the right direction.

you will have a much easier edit if you conform everything to one size, codec & frame rate first. Since you are planning to deliver at 1920×1080 at 25fps, why not just conform everything to that size & frame rate at the start?

You change the size in Compressor’s geometry tab, there’s a preset in one of the pulldowns for 1920×1080, and another for square pixels. Choose both. In the frames tab, set the resize to best quality. Since you’re going from progressive to progressive, leave the deinterlacer off.

It’s a common workflow to speed 23.98 or 24 up to 25 (commonly referred to as “24 at 25”), and Compressor has a simple way to do this.

In the Encoding tab, you set your output frame rate, then in the Frames tab you can tell Compressor how you want to do this. I think the bottom pulldown in the Frames tab phrases the option “so all frames play at 25”. This speeds up the video without redrawing any of the frames, so there’s no loss of quality from changing the speed.

Changing the 30P is more problematic. Unless you want to slow it down 20%, Compressor will have to redraw the frames. You will tell Compressor to keep the speed at 100% to keep the final duration of the video the same.

With 60i or 60P material there’s always a 60i field or 60P frame where the new 24P frame will be created. Compressor start with this field or frame, and look at the fields or frames around it to interpolate the new 24P frame. With 30P, many of the 24P frames fall sort of in between 30P frames, so Compressor will have less information to use when drawing new frames.

The results may have ghosting, faint double images following the motion of objects in the frame, or other motion artifacts. It may look bad when paused, but can look ok when playing.

We faced this when shooting out a commercial to film last year that was shot at 30P. We thought it looked like crap when paused, but when we viewed the first print we realized that hardly anyone else would ever really notice.

Good luck!

Arnie
Post production is not an afterthought!
https://www.arniepix.com/

[Wiremu Harpuka]

Arnie-
thanks so much for your sage advice and clear explanation. I will dwell on this and await confirmation of my delivery specs’…I will look at the Compressor Docs’ as you suggest but my head starts to swim with it all when under pressure.

All best,
wiremu

[Matt Lyon]

Arnie, have you tried converting from 30P to 23.98 or 25P using “nearest frame” conversion instead of “highest quality” … this forces Compressor to simply throw away frames instead of trying to draw new ones. (I wouldn’t attempt this for interlaced material, BTW).

I used this technique for converting some 30P to 23.98 and was happier with the results (no ghosting) … but YMMV.

Matt Lyon
Editor
Toronto

[Arnie Schlissel]

[Matt Lyon] “Arnie, have you tried converting from 30P to 23.98 or 25P using “nearest frame” conversion instead of “highest quality” … this forces Compressor to simply throw away frames instead of trying to draw new ones. (I wouldn’t attempt this for interlaced material, BTW).”

I haven’t tried that. Maybe we’ll test it next time, Thanks!

Arnie
Post production is not an afterthought!
https://www.arniepix.com/