Re: [Avid-L2] Re: EBU R 128 / Calm act, HIGHLY COMMERCIAL

>
> I have no idea how loudness an true peak relate, (and in fact i think they
> don't relate at all...),
>

Correct. True peak means just that - an actual value of PCM data that
reaches -2 dBFs. Program material can have all sorts of peaks (that is what
is great about this loudness requirement, as it allows for more dynamic
presentation), just none of those peaks can go above -2 dBFs.

What we do here (in Pro Tools) is run our loudness measurement (in real
time, across the master bus), get the LKFS number, adjust overall gain to
hit the spec number, and then peak limit at -2 dBFs. A plugin on my master
in Pro Tools like Waves L2 can make both gain and peak limit adjustments
(transparently without adding any compression, if you know what you're
doing), so it's rather easy.

Adding yourself a peak limiter might be putting your app into overtime cost
(!). As long as you have the measurement for true peaks, you should be fine
in just reporting it. You may consider adding a feature that can change the
window of measurement for "momentary" loudness to shorter than 400 ms. as
true peaks are instantaneous (i.e. one sample).

-Mark



On Mon, Oct 22, 2012 at 9:32 AM, bouke <bouke@editb.nl> wrote:

> **
>
>
> Terry,
> Job is right on almost all points.
> This thing can find places where there is either a momentary peak that is
> too high (momentary means 400 Msecs), or Short peaks (short means 3
> seconds)
> This is BEFORE bringing the entire mix up or down to -24 LUFS (-23 for
> Europe).
> Since the peaks are relative to the current loudness, it does not make a
> difference if you measure before or after.
>
> What is slightly more complicated as i initially thought (after analyzing
> a
> couple of long form pieces), and hence i disagree with Job a bit,
> Short peaks happen more than i would think. Especially if a mix is
> compressed, the Short peaks can occur even if you're 2 dB below our
> trusted -9.
> On an uncompressed mix its way less likely to let this happen, even if you
> go over -9.
>
> For the legalizer part, yes, it does 'legalize', but only the Integreated
> Loudness (the overall measured loudness).
> This is NOTHING MORE than lowering / upping the entire mix!
> In theory it's possible to let this thing mix down the peaks, but i don't
> trust a machine to do this.
> (and it's very easy to go back, fix it yourself and try again. If you have
> the feedback on a problem and the TC, you'll probably hear what the specs
> are bitching about..)
>
> But it's getting more complicated for the US.
> A bit out of the FOX specs:
> ---------
> >>Fox requires that commercial material have a subjective loudness of -24
> >>LKFS
> <snip>
> >>The FNC/FBN target subjective loudness level is -24 LKFS.
> >>Instantaneous true audio peaks shall not exceed -2dBFS (BS.1771),
> >>while average peak audio levels should not exceed -8dBFS (EBU Tech 3205
> or
> >>equivalent).
> ---------
>
> First, LKFS is (about) the same as LUFS, where 1 LUF is called a LU.
> Now we got that part covered.
> Over here newspeak is to talk about LU's to describe loudness, relative to
> the overall loudness.
> But these specs do not speak about the Integrated / Momentary loudness!
> It's only Instantaneous / Average and are described in DBFS,
> (to add to the fun, the EBU Tech 3205 is concidered obsolete...)
>
> >> Instantaneous true audio peaks shall not exceed -2dBFS
> >>average peak audio levels should not exceed -8dBFS
> I have no idea how loudness an true peak relate, (and in fact i think they
> don't relate at all...),
> But i've got a gut feeling that with a Momentary loudness set to 8,
> and Short to 2, you're way covered (probably this is too conservative...)
>
> But if you have the -2 / -8 dBFS covered already, you can just use this to
> get to the desired LUFS.
>
>
> Bouke
>
> VideoToolShed
> van Oldenbarneveltstraat 33
> 6512 AS NIJMEGEN
> The Netherlands
> +31 24 3553311
> www.videotoolshed.com
>
> ----- Original Message -----
> From: "Job ter Burg (L2B)" <Job_L2@terburg.com>
> To: <Avid-L2@yahoogroups.com>
> Sent: Sunday, October 21, 2012 8:52 PM
> Subject: Re: [Avid-L2] Re: EBU R 128 / Calm act, HIGHLY COMMERCIAL
>
> Terry,
>
> Yes, but the idea is not so much eliminating offending elements, as any
> short peaks or loud or silent scenes are not the issue. Total overall
> dynamics is. So it is better to mix by your ears, then use this tool (or
> some of the pther more expensive ones) to measure it and bring it up to
> spec.
>
> Apparently, Bouke's too will tell you where the parts of the mix are that
> cause the needto normalize, so you could go back and tweak those.
>
> Bouke's tool otherwise seems to go by the same approach as Grimm Audio's
> LevelNorm (AudioSuite plugin, Avid compatible, R128 or A/85). This was
> specifically designed so that Avid editors would mix any way they want,
> then
> normalize the entire result to R128 or A/85. Even if you would mix to
> older
> norms (like European mixes used to be crushed flat at -9dBfs), or if you
> want your mix to have a specific compressed sound and very limited dynamic
> range, LevelNorm or LoudnessChange will indeed legalize it to either R128
> or
> A/85.
>
> Most mixers tell me they need to rely less on meters and more on actual
> creative mixing with these new standards. They need to set up their room
> to
> a certain dialogue level they like to go by, then mix as they feel is
> right
> creatively, rather than the other way around. Folks mixing for TV can
> finally actually mix again, rather than fighting their way into a
> brickwall
> limiter.
>
> J
>
> On Oct 21, 2012, at 20:08, "Terence Curren" <tcurren@aol.com> wrote:
>
> > Bouke,
> >
> > You are just lowering the entire mix to pass specs right? The better
> > approach would be to only lower the offending elements, but that can't
> be
> > done with a finished file. So your program is more like a legalizer, yes?
> >
> > --- In Avid-L2@yahoogroups.com, "bouke" <bouke@...> wrote:
> >>
> >> Guys (and Shirley),
> >>
> >> If you need to deliver to the new sound specs, this might be of help:
> >>
> >> http://www.videotoolshed.com/product/68/loudnesschange
> >>
> >> In short, it can analyze a mixdown (as a wave file), see potential
> >> trouble
> >> (short / momentary peaks) so you can fix them,
> >> and render the file to a new file while upping / lowering the mix to
> get
> >> to
> >> your desired LUFS.
> >>
> >> And it's blazing fast....
> >>
> >>
> >> Bouke
> >>
> >> VideoToolShed
> >> van Oldenbarneveltstraat 33
> >> 6512 AS NIJMEGEN
> >> The Netherlands
> >> +31 24 3553311
> >> www.videotoolshed.com
> >>
> >
> >
> >
> >
> > ------------------------------------
> >
> > Search the official Complete Avid-L archives at:
> > http://archives.bengrosser.com/avid/
> > Yahoo! Groups Links
> >
> >
> >
>
>
>


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