Field Blending

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Introduction

Field blending, also known as "ghosting" is a deinterlacing method that is unacceptable at SDA. It's too easy to get stuck with a cheap capture card and cheap software that will produce a video with this effect. I think there may also be some fault with the user. People new to video capturing/editing will think they've done something wrong when they see "all those weird lines" in an interlaced frame and choose a different and incorrect interlacing setting, most likely progressive field blending.


The field blending process

1. A single interlaced frame. It has two distinct fields, which I will call field A and field B, happening a split second apart.
Image:Fieldblending_ABi.png
2. The fields have been split. Field A has the even-numbered lines, while field B has the odd-numbered lines.

Image:Fieldblending_A1.png Image:Fieldblending_B1.png
3. The actual vertical height of field A and B. Nothing necessarily bad has happened yet...

Image:Fieldblending_A2.png Image:Fieldblending_B2.png
4. Problem number one! The fields are resized to the original height. Vertical detail is lost.

Image:Fieldblending_A3.png Image:Fieldblending_B3.png
5. The final stage. Field A and B are blended together at different opacities. The result is a "ghosting" effect.

Image:Fieldblending_ABfb.png


More examples

Image:Fieldblending_Zelda.jpg

Image:Fieldblending_mario.PNG

Retrieved from "http://speeddemosarchive.com/kb/Field_Blending"
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