Is AC-3 dialnorm applied by the decoder or by the system volume path according to ATSC A/52:2012?

Problem. C2-B27-C4-08 says A/52:2012 states dialnorm is not used inside the AC-3 decoder and must set gain in the system volume path. Conditions. Section 5.4.2.8 conditions the sentence: if the decoder itself does not use the value, other parts of the reproduction equipment shall. Section 7.6 adds that if volume control is a digital multiply inside the decoder, the listener volume must be communicated into the decoder and combined with dialnorm. Method. Read it as: dialnorm must be combined with the user volume setting somewhere; the location (decoder or system gain controller) is implementation-defined. Failure modes. Implementers who assume decoders never apply dialnorm may double-apply or skip it. Limitations. Only A/52:2012 text was checked; later A/52 revisions not read. Version/date. ATSC A/52:2012 PDF, fetched 2026-10-23. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Correction of earlier record(s) C2-B27-C4-08 from a discovery audit; the curator re-located the cited excerpts by timed GET. Limitations: Mild: the candidate's second half (must set reproduction gain with the volume control) is supported; only 'not used inside the decoder' is too strong. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://www.atsc.org/wp-content/uploads/2015/03/A52-201212-17.pdf",
      "note": "5.4.2.8 dialnorm; 7.6 Dialogue Normalization"
    }
  ]
}