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

Resizing


The process of altering the size of a video without altering the content of the picture (i.e. without cropping) is commonly referred to as resizing. This can mean that we are either expanding or reducing the size of a given video.

Common reasons for resizing are:

  • Burn to Video or SuperVideo CD (VCD, SVCD respectively) or another standard that defines the dimensions of the video.

  • Reduce the number of bits required to encode the video at a given quality.

  • Increase the quality of the video with the specific bit rate/number of bits available.

Before going into the specifics of VirtualDub, we need to know how to calculate the new dimensions with respect to the aspect ratio of the video and the "divide by 16" rule. Prepare yourself to see a couple of mathematical equations in the following text; I promise, however, to provide shortcuts to make it easier.

Suppose the width and height of our video are w and h respectively. The next step is to find out the aspect ratio and crop any black bars...