International TV exchange loudness spec (ITU-R BS.1864)
What a file has to measure to pass this spec, and where each figure comes from.
ITU-R BS.1864 sets the operational practice for loudness in the international exchange of digital TV: a target of −24 LKFS, with variations of up to 2 dB expected, as long as a file isn’t consistently at either edge. It sets no true-peak limit, so this page uses the ATSC A/85 figure of −2 dBTP as a safe limit. Where a country publishes no loudness spec of its own, BS.1864 is a sensible fallback. LC-1 checks a WAV against this spec in seconds, applies the necessary level change and true-peak limiting, and prints a compliant file.
| Check | Required | In LC-1 |
|---|---|---|
| Integrated loudness | −24.0 ±2 LKFS | Fixed with a level change |
| True peak | −2.0 dBTP max | Limited, with audition |
Worth knowing
BS.1864 sets −24 LKFS and expects variations of up to 2 dB, as long as a file isn’t consistently at either edge. It sets no true-peak limit: the −2 dBTP here is the ATSC A/85 figure, used as a safe limit. A sensible fallback where no local spec is published.
Data source(s)
- ITU-R BS.1864-1 (11/2023), Operational practices for loudness in the international exchange of digital television programmes
Figures taken from the documents above and last read on 22 October 2026.
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