Hmmm, it looks like the attach is introducing a new instance of x.
Maybe something like this will work:
process(x,y) = x,y <: x, attach(y, (Lk2 : vbargraph("LUFS",-90,0))) : _,_;
On Tue, Jul 13, 2021 at 6:14 AM Klaus Scheuermann <kla...@posteo.de> wrote:
> Hi Julius,
>
> but this makes two (or n) meters, right?
>
> I would like to attach the lufs meter (which only has one hbargraph) to
> a stereo signal and leave the stereo signal untouched.
>
> Here is the working code for the stereo lufs meter, but it ends up
> having 3 channels. If I terminate the last channel with (_,_,!) , the
> meter is optimized out too. What I need is a function Lufs_Meter_Stereo
> that does nothing to the stereo sound, but only adds one meter (and
> preferably takes no arguments): _,_ : Lufs_Meter_Stereo : _,_
>
> import("stdfaust.lib");
>
> // Highpass:
> // At 48 kHz, this is the right highpass filter (maybe a Bessel or
> Thiran filter?):
> //A48kHz = ( /* 1.0, */ -1.99004745483398, 0.99007225036621);
> //B48kHz = (1.0, -2.0, 1.0);
> //highpass48kHz = fi.iir(B48kHz,A48kHz);
> highpass = fi.highpass(2, 40); // Butterworth highpass: roll-off is a
> little too sharp
>
> // High Shelf:
> boostDB = 4;
> boostFreqHz = 1430; // a little too high - they should give us this!
> highshelf = fi.high_shelf(boostDB, boostFreqHz); // Looks very close,
> but 1 kHz gain has to be nailed
>
> kfilter = highshelf : highpass;
>
> // Power sum:
> Tg = 0.4; // spec calls for 75% overlap of successive rectangular
> windows - we're overlapping MUCH more (sliding window)
> //zi = an.ms_envelope_rect(Tg); // mean square: average power =
> energy/Tg = integral of squared signal / Tg
>
> //envelope via lp by dario
> lp1p(cf, x) = fi.pole(b, x * (1 - b)) with {
> b = exp(-2 * ma.PI * cf / ma.SR);
> };
>
> zi_lp(x) = lp1p(1 / Tg, x * x);
>
> // Gain vector Gv = (GL,GR,GC,GLs,GRs):
> N = 5;
> Gv = (1, 1, 1, 1.41, 1.41); // left GL(-30deg), right GR (30), center
> GC(0), left surround GLs(-110), right surr. GRs(110)
> G(i) = *(ba.take(i+1,Gv));
> Lk(i) = kfilter : zi_lp : G(i); // one channel, before summing and
> before taking dB and offsetting
> LkDB(i) = Lk(i) : 10 * log10 : -(0.691); // Use this for a mono input
> signal
>
> // Five-channel surround input:
> Lk5 = par(i,5,Lk(i)) :> 10 * log10 : -(0.691);
> // stereo
> Lk2 = Lk(0),Lk(2) :> 10 * log10 : -(0.691);
>
> process(x,y) = x,y <: (_,_), attach(x, (Lk2 : vbargraph("LUFS",-90,0)))
> : _,_,_ ;
>
>
>
>
>
> On 12.07.21 03:08, Julius Smith wrote:
> > Hi Klaus,
> >
> > I sympathize! Been there!
> >
> > There are various examples in demos.lib. This seems to be right, but
> > let me know if not:
> >
> > import("stdfaust.lib");
> >
> > level_meter(chan) = abs : max(ma.EPSILON) : 20*log10 :
> > hbargraph("Channel %chan [unit:dB]",-70,10);
> > meter_lk(N) = si.bus(N) <: ro.interleave(N,N) :
> > par(i,N,attach(level_meter(i+1)));
> >
> > // Test:
> > sig(i) = 0.1 * no.noise;
> > process = sig(1),sig(2) : meter_lk(2) : _,_;
> >
> > Where would be a good place for this in the Faust libraries or examples?
> >
> > Cheers,
> > Julius
> >
> >
> > On Sun, Jul 11, 2021 at 10:23 AM Klaus Scheuermann <kla...@posteo.de
> > <mailto:kla...@posteo.de>> wrote:
> >
> > Guys, I am biting my teeth out here, although it is probably super
> > simple... (making a new thread, as the lufs-loudness-meter is getting
> > quite full...)
> >
> > I have a function Lk2 which has 2 inputs and one output. The output
> does
> > not matter to me, but it contains a vbargraph meter.
> >
> > How do I make a function meter_lk2 that has 2 inputs, 2 outputs and
> no
> > arguments, that attaches Lk2 to it only for metering, passing through
> > the inputs to the outputs?
> >
> > process = _,_ : meter_lk2 : _,_;
> >
> > meter_lk2 = ???
> >
> > (mono is easy, but stereo is killing me.)
> >
> > Thanks,
> > Klaus
> >
> >
> > _______________________________________________
> > Faudiostream-users mailing list
> > Faudiostream-users@lists.sourceforge.net
> > <mailto:Faudiostream-users@lists.sourceforge.net>
> > https://lists.sourceforge.net/lists/listinfo/faudiostream-users
> > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users>
> >
> >
> >
> > --
> > "Anybody who knows all about nothing knows everything" -- Leonard
> Susskind
>
--
"Anybody who knows all about nothing knows everything" -- Leonard Susskind
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