Dolby System Support

[Carsten]

You could try a basic center extraction upmixer (e.g. mid-side-decoder in DCP-o-matic). Aside from using DCP-o-matic's mid side decoder, a cinema will usually have no means to upmix a center channel. Some digital cinema processors offer a matrix decoder, but not all cinemas know about this or know how to enable it. As the DCI world does not allow or endorses matrix encoded audio, this is never used for todays features.

I experienced this in past years quite often, and it suprises me that it still comes up today occasionally - some cinemas are not technically able to adjust playback volume between preshow/trailers and main feature. While some may say that it would be good if cinemas should not be able to adjust volume at all, this is simply not realistic. The cinema operator is the last one in line, and the only one in direct relation with a 'potentially' suffering audience (and suffering not only because of too loud, but also too soft playback).

Just today a thread came up on film-tech about a cinema in florida that is operating for two years or so, with no knowledge to set different volume between preshow and feature. What does that mean? It means that usually, the main features there will be played at a manually set preshow level ...

But it'd still love to see some numeric comparisons (textform would be fine) of current day movies.

Not so easy - most mainstream DCPs - the only reliable source for theatrical mixes - are encrypted, and it is not possible to perform an audio analysis on the file level (unlike trailers, which are always unencrypted). One would need to install a realtime/logging hardware 5.1/7.1 R128/LEQ meter in the booth. Not many cinemas are willing to invest that money. There are a few papers with detailed numbers for a bunch of mainstream movies, (as the one by Ion Allen), but those that I know are often still based on film (35mm) based sound tracks. The overall quality and dynamic ambition of high end mixes have certainly improved with the digital cinema rollout. Yes, there are still many that suck.

- Carsten

[Carsten]

BTW - I think that marked section of the table on the 'Simple DCP' website is plain wrong - unless I'm misinterpreting it completely.
85dB LEQ(M), neither 85dB Pink noise ref clearly does not equal -31LUFS. It's more like -14 LUFS. Boy, that DOES make a difference...

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Your -78dB LEQ(m)/-23.9LUFS/LKFS complies with my trailer level rule of thumb. For a 15min piece, it may be okay, but, depending on dynamics development and dramatic intention, it may be a bit on the soft side. Again, the longer the piece is, the more difficult it is to express loudness with a single number. What I am trying to achieve with explaining and applying the current R128/LUFS numbers in DCP-o-matic is just to help people to get into the right ballpark. That is, aim at -20 LUFS, and make sure to factor in wether your piece is preshow or 'main feature'. Nothing beats listening to the mix in a calibrated auditorium on proper full range speakers with the cinema processor set to the desired/standard setting for the specific presentation type/segment.

By the way - the actual cinema processor plays a role here, too. Dolby fader 7 reference is only valid AT 7 - not below. A setting of 5.5 on a Datasat processor equals a setting of 4.5 on a Dolby processor.

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- Carsten