Contrast Filter Sample

Description

Video transform filter that implements a contrast effect. This sample illustrates how to define and implement a simple custom interface. It also demonstrates how to use the CTransformFilter class to implement a simple effect filter.

Path

Source: (SDK root)\Samples\Multimedia\DirectShow\Filters\Contrast

User's Guide

The Contrast filter is a simple transform filter that adjusts the contrast of the video stream that is passed through it. It provides a custom interface for adjusting the contrast. The Contrast filter also uses the CBasePropertyPage class to provide a property page for applications that do not provide a user interface.

The Contrast filter adjusts the contrast by using a trick with palettes. The color palette of an image effectively determines how the image is interpreted. By changing the palette, the filter can change the contrast without changing the image pixels themselves.