Thanks Julius! On Wed, 2022-05-11 at 20:05 -0700, Julius Smith wrote: > > 1. how does this help if we need reference sine tones from another > > source? I did a series of test tones in Reaper, all normalised to - > > 18lufs. Here ist the test- > > audio: https://cloud.4ohm.de/s/c7ynWemXS9eXibH > > Ok, so you're saying you want to take these Reaper-generated sine > files as ground truth. I was just probing the system with known > sines, which I trust for sure. Well, yes, probably I trust them ;) I also loaded Klangfreund lufs meter and ebumeter. They all show the same.
> > 2. at 1000Hz and levels above -45db, the lufs readout seems > > plausible. Below -45dbfs, the meter falls to -69lufs. I don’t > > understand. > > This is curious. For me that behavior kicks in around -32 dBFS. It > goes away in double precision, so I think it has to do with > "max(ma.EPSILON)". > However, while EPSILON is indeed around -70 dB when interpreted as > power, it should not suddenly take a large drop like that. It should > just clip. > In any case, this is a trivial one - we can just use "faust -double" > (and probably should anyway). double precision is not available in faustide, right? I will try and install faustlive today. Or would you recommend some other ide solution? (I am on arch linux.) > > 3. probably just some coding style, but does amp = > > 10^(level/20); equals amp = level : ba.db2linear; ? > > Yes, no difference expected. "Finger macro" - fewer characters to > type :-) Yay :) > > 4. with amp = level : ba.db2linear; meter drops to -69lufs below - > > 40dbfs at 1000Hz… > > Same glitch as in 2, right? Yes. > So, it sounds like the filter polishing task is to make the Faust > implementation match Reaper, but how do we know Reaper is correct? > Since it's open-source, why don't we just copy its filters? Yes! Here is the code of their JSFX loudness meter: https://pastebin.com/Pu9CVeBC unfortunately, I don't understand JSFX language :( Do you? Thank you so much again for your help! Klaus > Cheers, > Julius > > On Wed, May 11, 2022 at 4:02 AM Klaus Scheuermann <kla...@posteo.de> > wrote: > > Hi Julius, > > > > Hm, I think the averaging time should not matter with continuous > > sine tones coming in, right? > > (According to specs, 0.4 is the value for ‘momentary’ and 3 for > > ’short term’.) > > > > Some questions about your test-program: > > > > 1. how does this help if we need reference sine tones from another > > source? I did a series of test tones in Reaper, all normalised to - > > 18lufs. Here ist the test- > > audio: https://cloud.4ohm.de/s/c7ynWemXS9eXibH > > > > 2. at 1000Hz and levels above -45db, the lufs readout seems > > plausible. Below -45dbfs, the meter falls to -69lufs. I don’t > > understand. > > > > 3. probably just some coding style, but does amp = > > 10^(level/20); equals amp = level : ba.db2linear; ? > > > > 4. with amp = level : ba.db2linear; meter drops to -69lufs below - > > 40dbfs at 1000Hz… > > > > Thanks for investigating with me :) > > > > Klaus > > > > > > > > > > Klaus Scheuermann > > kla...@posteo.de > > +491716565511 > > @schlunk:matrix.org > > 4ohm.de > > trummerschlunk.de > > > > > > > > > On 11. May 2022, at 04:50, Julius Smith <julius.sm...@gmail.com> > > > wrote: > > > > > > Hi Klaus, > > > > > > Could the averaging time be too small? I'm worried about the > > > line > > > > > > Tg = 0.4;// 3 second window for 'short-term' measurement > > > > > > The comment seems to indicate it should be "Tg = 3;", i.e., 3 > > > seconds of averaging instead of 0.4 s. > > > > > > Below is an expansion of your test program that allows for more > > > exploration. > > > > > > Cheers, > > > Julius > > > > > > import("stdfaust.lib"); > > > > > > freq = hslider("[0] Test Sine Frequency (Hz) > > > [unit:Hz]",1000,30,16000,1); > > > level = hslider("[1] Test Sine Level (dBFS) [unit:dBFS]",-10,- > > > 80,0,0.1); > > > avg = hslider("[2] Averaging Time (s) [unit:sec]",3,0.01,10,0.1); > > > > > > amp = 10^(level/20); > > > testSignal = amp * os.osc(freq); > > > > > > process = testSignal <: _,_ : lk2 : vbargraph("[3] LUFS S",-40,0) > > > : *(1e-7); > > > > > > //Tg = 0.4; // 3 second window for 'short-term' measurement > > > Tg = avg; > > > zi = an.ms_envelope_rect(Tg); // mean square: average power = > > > energy/Tg = integral of squared signal / Tg > > > kfilter = fi.highpass(1, 60) : fi.high_shelf(4, 1800); > > > > > > // 2-channel > > > lk2 = par(i,2,kfilter : zi) :> 10 * log10(max(ma.EPSILON)) : - > > > (0.691); > > > > > > > > > On Tue, May 10, 2022 at 7:00 AM Klaus Scheuermann > > > <kla...@posteo.de> wrote: > > > > Hi Julius, > > > > > > > > this is, of course, the way to go. > > > > > > > > I did some test with a series of sines, each at -18lufs, and > > > > found these filter settings to be quite close (except for the > > > > 30Hz): > > > > kfilter = fi.highpass(1,60):fi.high_shelf(4,1800); > > > > > > > > Hz lufs > > > > 30 -16.693 > > > > 60 -18.111 > > > > 80 -18.204 > > > > 100 -18.211 > > > > 130 -18.177 > > > > 180 -18.133 > > > > 250 -18.113 > > > > 300 -18.099 > > > > 400 -18.099 > > > > 600 -18.169 > > > > 1000 -18.405 > > > > 2000 -18.241 > > > > 3000 -17.894 > > > > 4000 -17.784 > > > > 6000 -17.503 > > > > 8000 -18.083 > > > > 10000 -18.026 > > > > 12000 -18.035 > > > > 14000 -17.784 > > > > 16000 -18.083 > > > > > > > > What I don't quite understand is why the values read a little > > > > different, every time I do the test with same filter settings > > > > and same sines. (I am on faustide.grame.fr). > > > > > > > > For my application, this should work fine. Out of curiosity, > > > > why do I approximate the filters? So that it works on all > > > > samplerates? > > > > > > > > Full test code is this: > > > > import("stdfaust.lib"); > > > > > > > > process = _,_:lk2:vbargraph("LUFS S",-40,0); > > > > > > > > Tg = 0.4;// 3 second window for 'short-term' measurement > > > > zi = an.ms_envelope_rect(Tg);// mean square: average power = > > > > energy/Tg = integral of squared signal / Tg > > > > kfilter = fi.highpass(1,60):fi.high_shelf(4,1800); > > > > > > > > > > > > // 2-channel > > > > lk2 = par(i,2,kfilter:zi):>10 * log10(max(ma.EPSILON)): - > > > > (0.691); > > > > > > > > Thanks!! > > > > Klaus > > > > > > > > > > > > > > > > > > > > On Sun, 2022-05-08 at 13:17 -0700, Julius Smith wrote: > > > > > Hi Klaus, > > > > > > > > > > To go after this, it would be useful to measure the > > > > > discrepancy for > > > > > some number of sinusoidal frequencies across the audio band, > > > > > with at > > > > > least one example including both single-channel and > > > > > multichannel > > > > > input. > > > > > Based on the filter approximations used, I would predict a > > > > > measurable > > > > > discrepancy around 1 kHz (guessed transition-frequency > > > > > tuning), and > > > > > very high frequencies (due to bilinear transform frequency- > > > > > warping). > > > > > > > > > > The high-frequency discrepancy should go away with > > > > > oversampling, even 2x. > > > > > > > > > > Glad to hear noise is looking good! > > > > > > > > > > - Julius > > > > > > > > > > On Sat, Jul 3, 2021 at 1:08 AM Klaus Scheuermann > > > > > <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 > > > > > > > > > > > > Specifications (in Annex 1): > > > > > > 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 > > > > > > > > > > > > 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 > > > > > > https://lists.sourceforge.net/lists/listinfo/faudiostream-users > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > "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
