Loudness measurement guidelines and techniques, Appendix a – Cobalt Digital COMPASS 9086 Embedded Audio Loudness Processor User Manual
Page 69
9086-OM (V4.3)
9086-SD PRODUCT MANUAL
A-1
Appendix A
Chapter 1
Loudness Measurement
Guidelines and Techniques
This appendix provides a condensed guide to practical techniques for properly
measuring and assessing loudness in various types of program material.
The content here is in general accordance with ATSC A/85, “ATSC
Recommended Practice: Techniques for Establishing and Maintaining Audio
Loudness for Digital Television”. This document is available free of charge
and can be downloaded by going to:
About Loudness Measurement Applied to Program Material
A very useful aspect of the loudness measurement model is that a target and a
measured end-assessment are based upon simple, single-value LKFS
measurements that can be unambiguously displayed and assessed. When
properly performed as described in this appendix, the LKFS measurement
model accommodates reasonable short-term loudness variations in most types
of professionally produced material without nuisance failure indications or
ambiguous results.
The loudness measurement model specified in ATSC A/85 uses the LKFS
loudness unit to provide the simple, single-unit value that can be used to
assess program material loudness. Basically, before an assessment is
performed, two important initial facets must be considered:
•
Target LKFS Value – This is the desired reading that is to be
observed for a given segment or piece of program material.
•
Measurement Technique – Consideration should be given in using
techniques that result in the most meaningful or representative LKFS
measurements. These techniques are described below, along with
techniques suggestions suitable for various types of program material.