What does “deinterlace method” do?

[D. Eric franks]

Deinterlacing can happen three ways:

* None: glue the two fields into a single frame (this is what happens by default when you upload to Vimeo/YouTube or whatever).
* Interpolate: toss away one of the fields, duplicate the other (at the cost of half of your precious HD resolution).
* Blend: combine the two fields into a sort of average.

It does affect the look of the video, however, I have three cautions:

1. When you see interlacing on a single, still frame (esp. one with fast motion), it is NOT necessarily a sign of a problem, unless you are trying to pull a still frame out. When the video is shown in all of its full-motion glory, it might look fine.
2. In Vegas, toggle the Preview window to display “Best (Full)” and Shift+B to render a section of video to see the results. Lower quality previews usually won’t reveal what the deinterlacing is doing.
3. It is often recommended to use Interpolate for fast-moving objects and video (like sports) because this will produce a sharper image and use Blend for other types of productions (like a drama), because the video will be a little softer. I’m not going to disagree with that and say it’s wrong, but, honestly, the “right” method is the one that looks best to you.

I have a video that actually shows all of this in action here: The Joy of Interlacing.

__________________
The difference between writing a book and being on television is the difference
between conceiving a child and having a baby made in a test tube.
— Normal Mailer
https://videopia.org

[Hugh Macdonald]

When does Vegas perform a deinterlace? All FX? Some FX? Only when changing from i to progressive?

Surely, if I am staying within SD there is no need to deinterlace? But perhaps when cropping or moving or converting from 1080i or PAL you would need to? But straight cuts — why deinterlace?

If I knew what actions caused a need to deinterlace, then I could choose which deinterlace method to use.

[Danny Hays]

Most green screen, chromakeying works better with progressive footage. Also play oround with a golf swing or b-bal bat swing, Interpolate seems to work better with fast moving video, where blend seems to work better with fast moving footge. Danny