By the way, the "*(0.5)" is because the mean-square envelope has no square root, so it's in power units. We should add something like this to basics.lib: power2db(g) = 10.0*log10(g);
On Wed, Jul 7, 2021 at 9:31 AM Julius Smith <julius.sm...@gmail.com> wrote: > That is strange - hbargraph seems to have some kind of a gate in it that > kicks in around -35 dB. > > In this modified version, you can hear that the sound is ok: > > import("stdfaust.lib"); > Tg = 0.4; > zi = an.ms_envelope_rect(Tg); > gain = hslider("Gain [unit:dB]",-10,-70,0,0.1) : ba.db2linear; > sig = no.noise * gain; > process = attach(sig, (sig : zi : ba.linear2db : *(0.5) : > hbargraph("test",-70,0))); > > On Wed, Jul 7, 2021 at 12:59 AM Klaus Scheuermann <kla...@posteo.de> > wrote: > >> Hi all, >> I did some testing and >> >> an.ms_envelope_rect() >> >> seems to show some strange behaviour (at least to me). Here is a video >> of the test: >> https://cloud.4ohm.de/s/64caEPBqxXeRMt5 >> >> The audio is white noise and the testing code is: >> >> import("stdfaust.lib"); >> Tg = 0.4; >> zi = an.ms_envelope_rect(Tg); >> process = _ : zi : ba.linear2db : hbargraph("test",-95,0); >> >> Could you please verify? >> >> Thanks, Klaus >> >> >> >> On 05.07.21 20:16, Julius Smith wrote: >> > Hmmm, '!' means "block the signal", but attach should save the bargraph >> > from being optimized away as a result. Maybe I misremembered the >> > argument order to attach? While it's very simple in concept, it can be >> > confusing in practice. >> > >> > I chose not to have a gate at all, but you can grab one from >> > misceffects.lib if you like. Low volume should not give -infinity, >> > that's a bug, but zero should, and zero should become MIN as I mentioned >> > so -infinity should never happen. >> > >> > Cheers, >> > Julius >> > >> > >> > On Mon, Jul 5, 2021 at 10:39 AM Klaus Scheuermann <kla...@posteo.de >> > <mailto:kla...@posteo.de>> wrote: >> > >> > Cheers Julius, >> > >> > >> > >> > At least I understood the 'attach' primitive now ;) Thanks. >> > >> > >> > >> > This does not show any meter here... >> > process(x,y) = x,y <: (_,_), attach(x, (Lk2 : >> vbargraph("LUFS",-90,0))) >> > : _,_,!; >> > >> > But this does for some reason (although the output is 3-channel >> then): >> > process(x,y) = x,y <: (_,_), attach(x, (Lk2 : >> vbargraph("LUFS",-90,0))) >> > : _,_,_; >> > >> > What does the '!' do? >> > >> > >> > >> > I still don't quite get the gating topic. In my understanding, the >> meter >> > should hold the current value if the input signal drops below a >> > threshold. In your version, the meter drops to -infinity when very >> low >> > volume content is played. >> > >> > Which part of your code does the gating? >> > >> > Many thanks, >> > Klaus >> > >> > >> > >> > On 05.07.21 18:06, Julius Smith wrote: >> > > Hi Klaus, >> > > >> > > Yes, I agree the filters are close enough. I bet that the shelf >> is >> > > exactly correct if we determined the exact transition frequency, >> and >> > > that the Butterworth highpass is close enough to the >> > Bessel-or-whatever >> > > that is inexplicably not specified as a filter type, leaving it >> > > sample-rate dependent. I would bet large odds that the >> differences >> > > cannot be reliably detected in listening tests. >> > > >> > > Yes, I just looked again, and there are "gating blocks" defined, >> > each Tg >> > > = 0.4 sec long, so that only ungated blocks are averaged to form a >> > > longer term level-estimate. What I wrote gives a "sliding gating >> > > block", which can be lowpass filtered further, and/or gated, etc. >> >> > > Instead of a gate, I would simply replace 0 by ma.EPSILON so that >> the >> > > log always works (good for avoiding denormals as well). >> > > >> > > I believe stereo is supposed to be handled like this: >> > > >> > > Lk2 = _,0,_,0,0 : Lk5; >> > > process(x,y) = Lk2(x,y); >> > > >> > > or >> > > >> > > Lk2 = Lk(0),Lk(2) :> 10 * log10 : -(0.691); >> > > >> > > but since the center channel is processed identically to left >> > and right, >> > > your solution also works. >> > > >> > > Bypassing is normal Faust, e.g., >> > > >> > > process(x,y) = x,y <: (_,_), attach(x, (Lk2 : >> > vbargraph("LUFS",-90,0))) >> > > : _,_,!; >> > > >> > > Cheers, >> > > Julius >> > > >> > > >> > > On Mon, Jul 5, 2021 at 1:56 AM Klaus Scheuermann < >> kla...@posteo.de >> > <mailto:kla...@posteo.de> >> > > <mailto:kla...@posteo.de <mailto:kla...@posteo.de>>> wrote: >> > > >> > > >> > > > I can never resist these things! Faust makes it too >> > enjoyable :-) >> > > >> > > Glad you can't ;) >> > > >> > > I understood you approximate the filters with standard faust >> > filters. >> > > That is probably close enough for me :) >> > > >> > > I also get the part with the sliding window envelope. If I >> > wanted to >> > > make the meter follow slowlier, I would just widen the window >> > with Tg. >> > > >> > > The 'gating' part I don't understand for lack of mathematical >> > knowledge, >> > > but I suppose it is meant differently. When the input signal >> > falls below >> > > the gate threshold, the meter should stay at the current >> > value, not drop >> > > to -infinity, right? This is so 'silent' parts are not taken >> into >> > > account. >> > > >> > > If I wanted to make a stereo version it would be something >> like >> > > this, right? >> > > >> > > Lk2 = par(i,2, Lk(i)) :> 10 * log10 : -(0.691); >> > > process = _,_ : Lk2 : vbargraph("LUFS",-90,0); >> > > >> > > Probably very easy, but how do I attach this to a stereo >> > signal (passing >> > > through the stereo signal)? >> > > >> > > Thanks again! >> > > Klaus >> > > >> > > >> > > >> > > > >> > > > I made a pass, but there is a small scaling error. I think >> > it can be >> > > > fixed by reducing boostFreqHz until the sine_test is nailed. >> > > > The highpass is close (and not a source of the scale error), >> > but I'm >> > > > using Butterworth instead of whatever they used. >> > > > I glossed over the discussion of "gating" in the spec, and >> > may have >> > > > missed something important there, but >> > > > I simply tried to make a sliding rectangular window, instead >> > of 75% >> > > > overlap, etc. >> > > > >> > > > If useful, let me know and I'll propose it for >> analyzers.lib! >> > > > >> > > > Cheers, >> > > > Julius >> > > > >> > > > 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 >> > > > >> > > > // 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 : 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); >> > > > >> > > > // sine_test = os.oscrs(1000); // should give –3.01 LKFS, >> with >> > > > GL=GR=GC=1 (0dB) and GLs=GRs=1.41 (~1.5 dB) >> > > > sine_test = os.osc(1000); >> > > > >> > > > process = sine_test : LkDB(0); // should read -3.01 LKFS - >> > high-shelf >> > > > gain at 1 kHz is critical >> > > > // process = 0,sine_test,0,0,0 : Lk5; // should read -3.01 >> > LKFS for >> > > > left, center, and right >> > > > // Highpass test: process = 1-1' <: highpass, highpass48kHz; >> > // fft in >> > > > Octave >> > > > // High shelf test: process = 1-1' : highshelf; // fft in >> Octave >> > > > >> > > > On Sat, Jul 3, 2021 at 1:08 AM Klaus Scheuermann >> > <kla...@posteo.de <mailto:kla...@posteo.de> >> > > <mailto:kla...@posteo.de <mailto:kla...@posteo.de>> >> > > > <mailto:kla...@posteo.de <mailto:kla...@posteo.de> >> > <mailto:kla...@posteo.de <mailto:kla...@posteo.de>>>> wrote: >> > > > >> > > > Hello everyone :) >> > > > >> > > > Would someone be up for helping me implement an LUFS >> > loudness >> > > analyser >> > > > in faust? >> > > > >> > > > Or has someone done it already? >> > > > >> > > > LUFS (aka LKFS) is becoming more and more the standard >> for >> > > loudness >> > > > measurement in the audio industry. Youtube, Spotify and >> > broadcast >> > > > stations use the concept to normalize loudness. A very >> > > positive side >> > > > effect is, that loudness-wars are basically over. >> > > > >> > > > I looked into it, but my programming skills clearly >> > don't match >> > > > the level for implementing this. >> > > > >> > > > Here is some resource about the topic: >> > > > >> > > > https://en.wikipedia.org/wiki/LKFS >> > <https://en.wikipedia.org/wiki/LKFS> >> > > <https://en.wikipedia.org/wiki/LKFS >> > <https://en.wikipedia.org/wiki/LKFS>> >> > > <https://en.wikipedia.org/wiki/LKFS >> > <https://en.wikipedia.org/wiki/LKFS> >> > > <https://en.wikipedia.org/wiki/LKFS >> > <https://en.wikipedia.org/wiki/LKFS>>> >> > > > >> > > > Specifications (in Annex 1): >> > > > >> > > >> > >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > >> > > >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> >> >> > > > >> > > >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > >> > > >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> > < >> https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-3-201208-S!!PDF-E.pdf >> >>> >> > > > >> > > > An implementation by 'klangfreund' in JUCE / C: >> > > > https://github.com/klangfreund/LUFSMeter >> > <https://github.com/klangfreund/LUFSMeter> >> > > <https://github.com/klangfreund/LUFSMeter >> > <https://github.com/klangfreund/LUFSMeter>> >> > > > <https://github.com/klangfreund/LUFSMeter >> > <https://github.com/klangfreund/LUFSMeter> >> > > <https://github.com/klangfreund/LUFSMeter >> > <https://github.com/klangfreund/LUFSMeter>>> >> > > > >> > > > There is also a free LUFS Meter in JS / Reaper by >> > Geraint Luff. >> > > > (The code can be seen in reaper, but I don't know if I >> > should >> > > paste it >> > > > here.) >> > > > >> > > > Please let me know if you are up for it! >> > > > >> > > > Take care, >> > > > Klaus >> > > > >> > > > >> > > > _______________________________________________ >> > > > Faudiostream-users mailing list >> > > > Faudiostream-users@lists.sourceforge.net >> > <mailto:Faudiostream-users@lists.sourceforge.net> >> > > <mailto:Faudiostream-users@lists.sourceforge.net >> > <mailto:Faudiostream-users@lists.sourceforge.net>> >> > > > <mailto:Faudiostream-users@lists.sourceforge.net >> > <mailto:Faudiostream-users@lists.sourceforge.net> >> > > <mailto: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> >> > > >> > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users >> > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users>> >> > > > >> > > >> > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users >> > <https://lists.sourceforge.net/lists/listinfo/faudiostream-users> >> > > >> > <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 >> > >> > >> > >> > -- >> > "Anybody who knows all about nothing knows everything" -- Leonard >> Susskind >> > > > -- > "Anybody who knows all about nothing knows everything" -- Leonard Susskind > -- "Anybody who knows all about nothing knows everything" -- Leonard Susskind
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