Loudness is the perceived intensity of sound — how loud it actually seems to a listener — which is a different thing from peak level. Two clips can hit the same peak yet feel very different in loudness because perception depends on sustained energy and on frequency: the ear is more sensitive in the midrange. Modern measurement captures this with K-weighting and gating (ITU-R BS.1770), reporting the result in LUFS. Getting loudness right is what platform normalization is about: deliver near a target and your content sits at a consistent level beside everything else, instead of being turned up or down or jumping in volume between programs and ads.
The book · Volume 4 of 7
Audio for Video: A Complete Guide to Sound in Video Products: From PCM and Codecs to Loudness, Accessibility, and Real-Time Voice Processing
Loudness is what viewers complain about when ads blast or dialogue disappears, and peak meters will not catch it. Volume 4 covers loudness in depth: LUFS and BS.1770 measurement, EBU R128 and ATSC A/85 targets, true-peak limits and normalization across streaming platforms. Written by Nikolay Sapunov, CEO at Fora Soft.
Getting loudness complaints, or rejections from a platform's delivery spec?
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