How much can this levels increase?

[lcanau]

Hello,

This graph is of a test checking the audio levels of the stereo version of a short film, which I would like to be as loud as possible (noise and confusion is part of the concept). The audio mixer is levelling it for EBU R 128, which, of course, is for broadcast and, as far as I know - partially from reading from knowledgeable people here - there's not exactly a standard for cinema. I know of a production house that goes for -19 LKFS when making DCPs for cinemas, but I don't know if that reflects some sort of "good practice" around here.

In the case of shorts, besides the variable of the theatre house volume, I think many festivals will make new DCPs to create one with several films for a certain screening. So I imagine that in some case the audio would be normalized for that effect so that some shorts don't play way too loud than others. (Or maybe they have notes and adjust during projection, I don't know.)

In any case, considering this graph, how much would it be safe to increase? 7-8 dBs?

dcp_levels.jpg

[cvila]

Ebu R128 is indeed for broadcast but given the fact that the short film has not been mixed in a calibrated dub stage, it is a safe standard to follow for showing in a cinema.

I think you would get youself into problems if you raise the level 7-8 dB, thus consistently hitting full scale most of the time. It can damage equipment and people's hearing if the theater is calibrated for standard loudness.


Check the specification of the festival or talk to them, they probably have some guidance regarding loudness.

Otherwise you may get the opposite effect, it will be marked as "too loud" and taken down on playback

[Carsten]

LUFS and LEQ are in the right ballpark for a general presentation - a bit on the soft side. Technically, you can add +8dB before you get into peaking. If you want the audio to have some impact, I would probably give it 3 or 4 dB+. It depends a bit on the screening/leveling habit's of the festival.

[lcanau]

Thank you for the replies. Normally we send the same DCP to all festivals, I would make adjustments only if there's some specific requirement. I've seem a lot of variations on the levels on our previous DCPs, both in LUFS and in peek, but since noise is part of the concept of thie film, I was wondering is it isn't too conservative. We still have to work on the 5.1 mix, though, which should go to most screenings.

Obviously I don't want to have it too loud all the time, but from I what I read here if it's below 0 dB it won't distort, right? Of course, I might not understand the full details between peeks and LUFS, but I was thinking that maybe we can have the mix a bit higher and then normalize it for broadcast of for specific screenings that require specific loudness levels. I hope I'm not talking nonsense.

[Carsten]

LUFS is an actual measure of the perceived loudness (as is LEQ(m)). Peak is just a technical term that is used to prevent clipping/distortion. In practical terms, your peak should never actually reach 0dB, but can be as close as possible, so, -0.1dB True Peak is absolutely okay. Even 0dB true peak would be okay, if it would only be single audio samples hitting that value (no consecutive samples at 0dB). But as there are no ways in DCP-o-matic to analyse that condition, you should simply stay below 0dB true peak.

A LUFS number below 20 (-18,-16) will be louder than one well above 20. The loudest trailer I have seen so far was the official Star Wars 8 trailer, which came at around -13.3LUFS and was REALLY loud. It still adhered to international trailer leveling standards.
I would suggest a LUFS value of -18 for your short.

Maybe this will give you some more insight:

viewtopic.php?p=3576#p3576

SInce then, DCP-o-matic also learned to compute LEQ(m), and LEQ(m) is for cinema use, while LUFS is for Broadcast use. Both still make some sense in their corresponding domains, but when talking to professionals, you should use the respective proper terms.

Max allowed LEQ(m) values for commercials in cinema ('SAWA') is 82dB LEQ(m), for movie trailers ('TASA'), it is 85db LEQ(m). So trailers are allowed to be a bit louder than commercials. There is NO official loudness limit for features or shorts, although you are strongly advised to stay below these numbers as they are complaint threshold levels.

[lcanau]

Thank you for the detailed explanation. I will try to have the level slightly increased but not too much. We'll have the opportunity to check it in a projection room later.

[lcanau]

This is the 5.1 mix. -16.86 is a bit too high...?
We will test it in a projection room but maybe only in 3 or 4 weeks

DCP_levels2.png

[Carsten]

Yes, even if you want it to be loud, that could be a bit too much.