Table of Contents
Advertisement
1
Loudness Measurement Overview
ITU-R BS.1770-1 – ATSC A/85 Overview
1-2
•
Chapter 3, "Operating Instructions" – Provides overviews of
operating controls and instructions for using the Audio Loudness
Meter option.
This chapter contains the following information:
•
Loudness Measurement Overview (p. 1-2)
•
Audio Loudness Meter Functional Description (p. 1-5)
•
Technical Specifications (p. 1-10)
Note:
Refer to ITU-R BS.1770-1, "Algorithms to measure audio programme loud-
ness and true-peak audio level" and ATSC A/85, "ATSC Recommended Prac-
tice: Techniques for Establishing and Maintaining Audio Loudness for Digital
Television" for more information.
This option provides an Audio Loudness Meter that performs loudness
measurement based on the methods described in ITU-R BS.1770-1 and ATSC
A/85. This recommendation considers the L, R, C, Ls, and Rs audio inputs of
a 5.1-channel complement and performs a measurement on each channel that
sums the weighted acoustical energy present in each channel over a given
sampling period (see Figure 1-1). These individual channel measurements are
summed, resulting in a single, overall numerical quantity (called "LKFS"; as
defined as loudness, K-weighted, relative to full scale) which can be used as a
pass/fail value of the program material when assessed against a target LKFS
value. Note that stereo and monaural sources can also be used; however, LFE
and auxiliary channels are never included in an LKFS assessment.
AUDIO LOUDNESS METER OPTION (+LM-C, +LM-P) MANUAL SUPPLEMENT
Loudness Measurement Overview
OPT-SW-LM-MS (V2.9)
Advertisement
Table of Contents
