Re: [DCP-o-matic] EBUR128 - Loudness audio normalisation (LUFS)

Am 24.02.2016 um 02:13 schrieb Carl Hetherington via DCPomatic: Carl, I assume this filter creates summed output of all channels in order to create a somehow realistic rendering of auditorium loudness according to EBU broadcast-specs. I have watched the numbers while playing around with audio levels a bit, but currently I am not sure how to use it. I recently assisted a short film project and it occured to me that common information on the net is somewhat shorthanded with respect to audio levels - most amateurs or semi-pros ask 'Which level should I aim for in cinema, give me a dB number'. Now, on forums, very often they get the answer: 'Must be 82dB LEQ(M) for advertising, and 85dB LEQ(M) for features' But that is wrong - these are the maximum allowed levels. It doesn't mean that once you have leveled your audio track as such, it has the proper listening volume. These numbers are there to avoid customer complaints and warrant adherence to local standards like SAWA. They are maximum numbers that shouldn't be exceeded. An intimate dialog scene leveled to 85dB LEQ(M) would be much to loud. There IS NO number that expresses the 'proper' volume for your specific feature, short, or ad. The only way to approach the proper audio levels in a cinema is to listen to your soundtrack in a controlled listening environment that has ben calibrated using common pink-noise techniques like 85dB SPL(C) for screen channels and 82dB SPL(C) for surround channels. Even that leaves some effects out, but it is the only way to come close to an international standard for cinema audio levels. It's basically the same as with brightness - there is no standard on how white a snow scene has to be or how orange a sunset. It is your artistic decision. Same with audio levels. The only way to get this right is to use a solid calibrated viewing and listening environment and apply your own choice. - Carsten