Book Image

Learning VirtualDub: The Complete Guide to Capturing, Processing and Encoding Digital Video

Book Image

Learning VirtualDub: The Complete Guide to Capturing, Processing and Encoding Digital Video

Overview of this book

VirtualDub is one of the most popular video processing applications for Windows. As an open source application, it's free, and is constantly updated and expanded by an active community of developers and experts. VirtualDub is particularly popular for capturing video from analogue sources such as video tape, cleaning up the image and compressing it ready for distribution over the Internet. This book provides a rapid and easy to use tutorial to the basic features of VirtualDub to get you up and running quickly. It explains how to capture great quality video from various sources, use filters to clean up the captured image and add special effects. The book also shows how to use VirtualDub to cut and paste video to remove or insert sequences, including removing ad breaks or trailers. It goes on to cover the art of effective encoding and compression, so you end up with great quality videos that won't hog your bandwidth forever. VirtualDub is the fastest and most effective way to capture, process and encode video on your PC. This book gets you started fast, and goes on to give you full control of all the features of this legendary tool.
Table of Contents (14 chapters)
Learning VirtualDub
Credits
About the Authors
Introduction

Chapter 10. Compressing: A World of Codecs

We have used the term ‘codec’ quite a lot in earlier chapters without defining what it means. A codec is just a compression and decompression engine. It does not refer only to digital video, but also to audio and other forms of data. However, in this book, we are only concerned with video and audio codecs.

Previously, we classified codecs as lossless and lossy. This classification is only evident for audio and video codecs. Data compression does not tolerate data losses, so all data codecs are lossless. Imagine compressing a very important archive of documents only to find they are corrupted when you decompress them! You probably do not want that to happen with your video or audio. Lossy video codecs exploit redundancies in the video frames and insensitivities of the human visual system to reduce the amount of data required to represent the original video.

Audio codecs take advantage of properties of the human auditory system, striving to squeeze...