- Adobe After Effects
- FieldsKit Deinterlacer -Plugin
- FieldsKit Reinterlacer -Plugin
- Take Converter
This article is written for VFX people, as well as the curious video engineer. I will Frequently say 60, when I mean 59.94, or 30, when I mean 29.97. I will use the two terms interchangeably, but there is a difference. One of the main differences is that in the modern NTSC broadcast wold 30, and 60 almost never exist. This is a world where 29.97 and 59.94 are used, but people will frequently call them 30 or 60 for the sake of convenience. If you wish to read up on why it is 29.97, not 30 and 59.94 not 60 and the history of black and white compatible color television please read here.
Basics of interlacing
Interlacing is a way of capturing video at a given frame rate, but capturing 2 different timing intervals in a single frame. This means that video captured at 30fps with interlacing will have motion which looks much more like 60 frames progressive rather than 30 frames progressive. This smoother motion has a trade off of halving the resolution of a single frame into two distinct times. It essentially allows the broadcaster to double the perceived frame rate, without consuming additional bandwidth.
Extracting Take Data
Take data is extracted using TakeConverter. The whole process works normally, except for one thing. TakeConverter and Previzion output data for each field of video, rather than frame when working with an interlaced sequence. This is because each frame of video consists of alternating lines from two distinct times. This means that 1 second of 60i/30fps footage will have 60 different camera position captured for it. Compared to 30P/30fps video, which will only have 30 data points in a 1 second clip.
Shoot a 50i or 60i clip
edit the clip in your NLE of choice
Export clip normally from NLE
In After Effects create a sequence that is 50fps if you shot 50i, or 59.94fps if your footage was shot 60i
Import your interlaced clip to After Effects
If you don’t see comb artifacts on your interlaced clips right click the clip then “Interoperate footage>Main” or Ctrl+alt G
Then under “Fields and pull down” turn Separate fields “Off”
The comb artifact should now show up in section of the video with motion.
Drop the interlaced clip into your 59.94fps or 50fps comp
Apply the “Fieldskit Deinterlacer” to the clip
The settings for the for the deinterlacer are the following:
- Timing: 2x FPS
- Field order: Upper, but check on the motion of your clip to make sure when you play back it isn’t choppy, if it is try lower
- Fill method:Use “Best 5 Neighbor” you lose a tiny bit of resolution, but the video will be smoother, which is necessary for post tracking.
- Detect Motion: No Motion Mask
You are done deinterlacing, now export your clip. It is ready to be worked on in After Effects, Maya, Nuke or any other frame based production software as a 50p/60p clip
Import 50p/60p clip
Create a comp that is either 25fps, or 29.97fps depending on if you are working in PAL or NTSC
Drop your 50p/60p clip into the comp
Apply the FieldsKit Reinterlacer with the following settings:
- Field order: should be the same as what you originally output.
- Output type: Half frame rate
Export your comp at it’s native interlaced frame rate.