Dolby Atmos, as technology People & Technology

Dolby Atmos is an object-based spatial audio format developed by Dolby Laboratories. Unlike traditional channel-based surround (5.1, 7.1), which assigns audio to fixed speaker positions, Atmos treats sounds as individual objects that can be placed and moved in three-dimensional space — including overhead. A Dolby Atmos mix can contain up to 128 audio tracks and 118 simultaneous objects.

On UHD Blu-ray, Dolby Atmos is encoded as metadata on top of a Dolby TrueHD 7.1 lossless core. Players without Atmos decoding fall back to the TrueHD 7.1 track; players without TrueHD fall back further to a lossy Dolby Digital Plus core. The format is backward-compatible through the entire chain.

For catalog film releases, an Atmos remix is a creative decision, not a technical necessity. The original theatrical mix of a 1970s or 1980s film was designed for a specific speaker configuration. An Atmos remix redistributes those elements into a three-dimensional field — sometimes effectively, sometimes controversially. Several physical media pages in this vault note when an Atmos remix was or was not included, as the presence of the original theatrical mix in lossless form is often considered more important by collectors.

In the wiki

Film	Page	Summary
Body Double (1984)	Physical Media Releases (Body Double)	Sony's 2024 4K UHD is the first Body Double release with a Dolby Atmos mix (TrueHD 7.1 core)
Blow Out (1981)	Physical Media Releases (Blow Out)	Criterion's 2022 4K UHD notably lacks an Atmos remix despite the film's plot hinging on the act of listening