How is Loudness measured in Dolby Atmos?

  • Jun 7, 2023
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How is Loudness measured in Dolby Atmos?
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sryan1.5548589383693281E12, 5/25/2023 10:17 PM
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MCW, 6/7/2023 11:35 PM
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During encoding Dolby Digital Plus with Dolby Atmos for file-based (non-live) content, loudness measurement according to ITU-R BS.1770-4, with optional Dialogue Intelligence speech-gating, is performed automatically.

Object-based immersive Dolby Atmos content
For object-based immersive content, loudness is measured by rendering to a known channel configuration, specifically 5.1 channels, and then measuring the loudness of this 5.1-channel render according to ITU-R BS.1770-4. 

Channel-based immersive content
For channel-based immersive content, Annex 3 of ITU-R BS.1770-4 specifies an extension to the loudness measurement method that supports channel-based content with height channels. This includes modifications to the weighting coefficients according to both the azimuth and the elevation of each loudspeaker channel for loudspeaker layouts specified in ITU-R BS.2051. 
Dolby Atmos & Dolby Audio




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