SMPTE RP 187:1995

Abtract:

Most video standards documents specify tolerances for individual picture blanking edges; center and aspect ratio are only implied by nominal blanking values, and vary as the blanking edges move within permitted tolerances. Modern techniques of post-production require compositing of images generated by multiple devices (and sometimes originated in different video standards). These techniques demand a degree of precision not afforded by the implied definitions of center and aspect ratio. — This practice defines picture center and aspect ratio for a number of existing video standards, and provides an extensible technique that may be used to define center and aspect ratio for future standards. Test charts and test patterns are described which permit image generation and display devices to be calibrated to the recommended geometry. Recommendations are made for blanking widths at various stages of the production/post-production process. Additionally, a definition is provided for a set of recommended screen units permitting simple cross reference between standards with aspect ratios of 4 × 3 and 16 × 9. — The practice is intended to be used for calibration of image generation and display devices. It is also intended as a reference for designers of such equipment (particularly graphics devices), and for designers of processing equipment such as image-manipulation devices.