【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 Keying
Color 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.html
Topics 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
