【教程介绍】在AE软件中进行视频抠像也是我们后期工作的一个重要区域，本期教程将详细的讲解利用Color Keying（色度键）对绿屏画面进行抠像处理，通过一系列的优化处理使得画面更加的干净彻底，然后对抠像画面进行了后期合成处理。

教程为高清视频教程，英语对白（无中文字幕），含工程文件Lynda – After Effects Compositing Essentials Color KeyingColor keying, also known as chroma keying, lets you shoot a foreground scene and insert it into virtually any background; this can save you money and allow you to create shots that are impossible or highly dangerous to take as a single shot.

For it to be effective, the key is in the details.

In this course, Mark Christiansen shows how to produce feature-film-quality keys in After Effects that fit well within their new scenes, while retaining the subtle details—be they strands of hair or soft or translucent edges—that make the results believable.

Beginning with a brief explanation of the keying process, Mark takes you through the steps involved in creating a perfect green-screen key: generating a rough matte, eliminating color spill and matte lines, and refining problematic edges.

He shows how to work with Keylight and Primatte—two indispensable keying tools in After Effects—and explains when to use one over the other.

And for times when green screen won’t work, he shows how to generate high-contrast mattes, or luma keys, based on the luminance data in your footage.

Last, learn about compression and how to prep a shot for keying.

官网：http://www.lynda.com/After-Effects-tutorials/114914-2.htmlTopics include: 知识点What is color keying?  什么是色度键Using garbage mattes   蒙板利用Getting started with Keylight   简单抠像Understanding the Screen Color, Clip Black, and Clip White adjustments  分析画面Eliminating spill with Advanced Spill Suppressor   细节处理Using Key Cleaner to refine edges automatically   边缘优化Dividing a matte with holdout mattes   图层遮罩Breaking down a complex color key   复杂操作Creating a luma key with Extract  使用亮度键Setting up sky replacement   贴图置换Using Refine Soft Matte to improve edge detail   用蒙板细化边缘Feathering edges with Channel Blur   羽化/模糊通道Knowing when to avoid green screen   绿屏抠像技巧Prepping a shot for keying   镜头合成

【教程下载】AE教程：绿屏抠像训练教程 Lynda – After Effects Compositing Essentials Color Keying