# XFree86 Video Timings HOWTO

## Eric S. Raymond <esr@thyrsus.com>

Version 3.0, 8 Aug 1997

How to compose a mode line for your card/monitor combination under XFree86. The XFree86 distribution now includes good facilities for configuring most standard combinations; this document is mainly useful if you are tuning a custom mode line for a high-performance monitor or very unusual hardware. It may also help you in using xvidtune to tweak a standard mode that is not quite right for your monitor.

### 1. Disclaimer

### 2. Introduction

### 3. How Video Displays Work

### 4. Basic Things to Know about your Display and Adapter

  4.1. The monitor's video bandwidth:
  4.2. What these control:

### 5. Interpreting the Basic Specifications

  5.1. About Bandwidth:
  5.2. Sync Frequencies and the Refresh Rate:

### 6. Tradeoffs in Configuring your System

### 7. Memory Requirements

### 8. Computing Frame Sizes

### 9. Black Magic and Sync Pulses

  9.1. Horizontal Sync:
  9.2. Vertical Sync:

### 10. Putting it All Together

### 11. Overdriving Your Monitor

### 12. Using Interlaced Modes

### 13. Questions and Answers

### 14. Fixing Problems with the Image.

  14.1. The image is displaced to the left or right
  14.2. The image is displaced up or down
  14.3. The image is too large both horizontally and vertically
  14.4. The image is too wide (too narrow) horizontally
  14.5. The image is too deep (too shallow) vertically

### 15. Plotting Monitor Capabilities

### 16. Credits