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 _______________________________________________ Faudiostream-users mailing list Faudiostream-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/faudiostream-users
