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by potamic
262 days ago
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It does mention compliance with the CALM act, which lays out the precise methodology by which loudness will be measured [1] > The Calm Act refers to A/85, and A/85:2013
specifies BS.1770 (specifically referencing BS.1770-1) as
the source of its loudness measurement techniques
(1770-2 did not exist at the time A/85 was finalized). So
BS.1770-1 currently serves as the yardstick by which
U.S. television programming will be evaluated for CALM
Act compliance. > BS.1770 recommends the Leq(RLB) measurement
algorithm, where Leq(W) the frequency weighted sound
level measure, xw is the signal at the output of the
weighting filter, xRef is the reference level, and T is the
length of the audio sequence. > The drawback of BS.1770 as originally conceived is that
it measures average loudness over the entire length of
content. This may be fine if the loudness is fairly
consistent over time. If not, a quiet section of content
may, as illustrated in Figure 5, bias the average level so
that it measures as acceptable despite having some
sections that are unacceptably loud. [1] https://www.telestream.net/pdfs/whitepapers/wp-calm-act-comp... |
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> Commercial Advertisement Loudness Mitigation (CALM) Act of 2010