DBFS Scale - Final Cut

I know this question is really about Final Cut, however I hope someone can help.

 

When I export a project to Final Cut XML and open it in FC the meters are not dBFS. Can they be changed in FC? A little confused why FC uses dB (VU) scale and not dBFS.

When I export a project to Final Cut XML and open it in FC the meters are not dBFS. Can they be changed in FC? A little confused why FC uses dB (VU) scale and not dBFS.

That would be odd indeed... are you sure they're not dBFS? While I couldn't find a definitive source regarding this, the manual mentions a peak meter, only talks about 'dB', but then in the glossary goes on to state that....

 

decibel (dB)

Unit of measurement for sound levels; a logarithmic scale used to describe the loudness of sound as perceived by the human ear. (1 dB corresponds approximately to the smallest volume change that the average human ear can perceive.) For digital audio, dBFS is the standard decibel unit of sound level measurement.

Final Cut Pro X uses a digital peak meter with a dBFS scale by default.

 

0 is maximum (full scale) and anything above that is overload in floating points (up to +6 dB shown).

 

If you can change the meters to a VU/RMS style I don't know where. How do your meters look?

 

I could have sworn on one FCPX project I had a true dBFS scale with no floating points but now I can't recreate it, so I must be wrong. So enlighten me as an audio guy, why would a video editor need up to +6 db over 0dBFS for peaks? Shouldn't the audio in a video project be in the -20 to -12dBFS range? This stuff fascinates me by the way and if you can point me to any reading on the subject to understand it better I would love it! Thanks so far for the help!

I could have sworn on one FCPX project I had a true dBFS scale with no floating points but now I can't recreate it, so I must be wrong.

The meter I've posted above is a "true dBFS scale" meter. It goes from minus infinity to full scale (0 dBFS) and shows up to +6 dB overs, which is possible because it's floating points math.

 

Perhaps Apple updated the looks of the meter in FCPX, there was a major UI update at some point.

 

Shouldn't the audio in a video project be in the -20 to -12dBFS range? This stuff fascinates me by the way and if you can point me to any reading on the subject to understand it better I would love it! Thanks so far for the help!

You're welcome!

 

There's no standard for where the peak level in a video project should be. Watch out if somebody claims otherwise. Sometimes people have heard that e.g. a peak of -18 dBFS is referenced to 0dBu in the analog domain or that one particular broadcaster specifies such-and-such peak level, and they mix things up.

 

If you're doing a video commercial for TV, the loudness target is most likely -23 LUFS (I) as specified by the EBU in the R128 regulation in Europe, and nearly the same specs by ATSC in A/85 in the US. The peak level should be no higher than -1 dBTP (that's TP for True Peak, not FS for Full Scale) for R128.

 

If you're doing a commercial for a movie theather it'll likely be LEQ(m)82 dB SAWA or similar.

 

If you're doing a video project for YouTube you will currently do well to hit somewhere between -11 and -14 LUFS (I), although YouTube are constantly tweaking their loudness normalization algorithm. Recently however, it's become possible to see exactly how much static gain reduction they're reducing your audio by. The peak level doesn't matter that much, but if your target is just above -14 LUFS (I) then it's not difficult to go for -1 dBTP (again TP, not FS) for safety reasons, i.e. to avoid inter-sample peak overs during the lossy conversion process to AAC or at the D/A stage.

 

If you're doing something else for a TV channel, like a documentary, there's no telling what their specs are: ask the broadcaster.

 

All of the standards I mention above are so-called integrated loudness standards. Integrated (I) in this case means "measured from start to end of the project". Peak specs are normally in dBTP and usually irrelevant as long as you're not above -1 dBTP (minimum 4x oversampling during measurements). Some specs include short-term loudness demands or dynamic range demands, but that's not as common.

 

So enlighten me as an audio guy, why would a video editor need up to +6 db over 0dBFS for peaks?

This peak meter in FCPX is there to make sure you're not digitally overloading, and if you are, by how much so you can turn your audio down or process it accordingly. But you'll need a real integrated loudness meter with at least R128/A85/Leq and True Peak to do professional work within specs.