---
title: "Dolby Digital Plus Primary Level Metadata Parameter and What It Does"
slug: "dolby-digital-plus-primary-level-metadata-parameter-and-what-it-does"
updated: 2024-12-19T11:21:38Z
published: 2024-12-19T11:21:38Z
canonical: "docs.telosalliance.com/dolby-digital-plus-primary-level-metadata-parameter-and-what-it-does"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.telosalliance.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Dolby Digital Plus Primary Level Metadata Parameter and What It Does

"Primary Level" is a Dolby Digital Plus metadata parameter whose main function is to attenuate/duck the level of a Dolby Digital Plus Primary Audio Stream. In order for this parameter to have any effect, a Secondary Audio Stream must be present.

For example: Having director commentary *(as a secondary audio stream)* and the main program play simultaneously. When the director speaks, the primary audio will duck or boost according to the value specified for primary level. This field specifies a scale factor that should be applied to the program during decoding. Valid values are 0 to 63, with 0 interpreted as mute, and 1-63 interpreted as -50 dB to +12 dB of scaling in 1 dB steps. That said, the default value of "51" = 0dB or no gain change.