signal, introduced new units of measurement: Normalisation recommends normalising audio at the target level of . This measurement is the integrated loudness calculated over the whole duration of the programme and in the entirety of its contents (i.e. without emphasising specific foreground elements, such as voice). A deviation of is permitted. When practical limitations prevent achieving this accuracy (specifically, less predictable materials such as live mixed programmes), a wider tolerance of is permitted. Furthermore, the whole programme must not exceed the peak level of . To ensure loudness meters developed by different manufacturers provide the same reading, EBU Tech 3341 defines EBU Mode which describes how to perform the measurement using the ITU-R BS.1770 recommendation. Metering EBU Mode specifies three distinct methods which analyse loudness over three different timeframes: Momentary (M), using a sliding time window of , best describes the instantaneous loudness; Short-term (S), using a sliding time window of 3 seconds, describes a more averaged, less event-dependant loudness of the past three seconds; Integrated (I), averaging the programme from start to finish, describes the loudness of the whole programme. Real-time meters must provide an update rate of at least for short-term meters and of at least for integrated loudness meters. To prevent silent passages of a programme from misrepresenting the overall loudness measurement, integrated loudness is measured through two gating functions: absolute and relative. The detection gate, specified in ITU-R BS.1770-4, considers silence the portions of audio in which the signal falls below the absolute threshold of ; similarly, the relative gate also drops incoming loudness data if the average level falls below the current integrated loudness value. Measurement is not gated in momentary and short-term loudness metering. Implementation EBU and EBU Mode have been implemented by several software developers, audio technology companies and content distributors, including Adobe, Apple, Dolby, iZotope, Magix, PreSonus, Sony, Steinberg, TC Electronic, Toyo and Waves. Real-time metering plug-ins aid engineers in their mixing decisions and in delivering -compliant programmes, while broadcasters and content distributors can check and normalise whole programmes by performing a faster-than-real-time analysis; programmes produced before the recommendation are likely to be lowered in volume to match the target level. Ebumeter is software for Linux that provides level metering according to EBU R 128. Adoption and aftermath The recommendation encourages the use of a wider dynamic range in production but does not restrict the use of dynamic range compression. In essence,