My experience with Faust, and some more general observations

giuliomoro

DragonSF It's working now

good news!

DragonSF ounds a little bit different compared to faust playground,

hmmm maybe you have some analog inputs being used in your dsp scripts and these are not connected to anything and left floating on the board?

DragonSF And next, how to include this server as a tab into the Bela IDE (I have no idea).

I guess we can think about that in a larger revision of the IDE we are going to do in the next few months. I guess in the meantime it is fine to have it in a different tab?

DragonSF

giuliomoro Yes, I'm fine with having the GUI for Faust in a different tab. And think about creating a symbolic link for a new Faust project directly in the project directory. We need also some sort of automatic faust compile of the DSP file. JIT takes too long or doesn't load correctly.

giuliomoro

Oh what do you mean "JIT doesn't load correctly"?

We expect JIT to be faster than Faust->C++->binary, but I have not really benchmarked that yet. The jit-generated binary could then be cached to disk for faster startups (i.e.: comparable to the C++-generated binary) after the first compilation.

Maybe there is a way to start the webserver with a different root, without the need to create symlinks, will have to check the docs/source.

giuliomoro

giuliomoro We expect JIT to be faster than Faust->C++->binary, but I have not really benchmarked that yet

I mean that the time it takes to do the JIT should be faster than compiling dsp to C++ and C++ to binary, but the JIT happens when you start the program (and needs to be cached to disk: it is not being cached currently), while the C++ way happens before you start it.

How long does it take to compile the same FAUST code to C++ and compile the C++ code? Can you post the example dsp file?

DragonSF

That's strange, when I run this as jit, it took about 10min to start.

DragonSF

DSP file:

declare name "WaveGuide Sitar";
declare author "Romain Michon (rmichon@ccrma.stanford.edu)";
declare copyright "Romain Michon";
declare version "1.0";
declare licence "STK-4.3"; // Synthesis Tool Kit 4.3 (MIT style license);
declare description "This instrument implements a sitar plucked string physical model based on the Karplus-Strong algorithm using a randomly modulated delay line.";

import("music.lib");
import("instrument.lib");

//==================== GUI SPECIFICATION ================

    freq = nentry("h:Basic Parameters/freq [1][unit:Hz] [tooltip:Tone frequency]",440,20,20000,1);
	gain = nentry("h:Basic Parameters/gain [1][tooltip:Gain (value between 0 and 1)]",1,0,1,0.01); 
	gate = button("h:Basic Parameters/gate [1][tooltip:noteOn = 1, noteOff = 0]");
//freq = hslider("[1]Frequency[BELA:ANALOG_0]", 440,460,1500,1):smooth(0.999);
//gain = hslider("[2]Pressure[style:knob][BELA:ANALOG_4]", 0.96, 0.2, 2.0, 0.01):smooth(0.999):min(0.99):max(0.2);

//gate = hslider("[0]ON/OFF (ASR Envelope)[BELA:ANALOG_0]",0,0,1,1);

resonance = hslider("v:Physical Parameters/Resonance
	[2][tooltip:A value between 0 and 1]",0.7,0,1,0.01)*0.1;

//==================== SIGNAL PROCESSING ================

//stereoizer is declared in instrument.lib and implement a stereo spacialisation in function of 
//the frequency period in number of samples 
stereo = stereoizer(SR/freq);

//excitation envelope (adsr)
envelope = adsr(0.001,0.04,0,0.5,gate);

//the delay length is randomly modulated
targetDelay = SR/freq;
delayLength = targetDelay*((1+(0.5*noise)) : smooth(0.9992));
	delayLine = delay(4096,delayLength);

//the loop gain control the resonance duration
loopGain = 0.895 + resonance + (freq*0.0000005);
amGain = 0.1*gain;

//feedback filter is a one zero (declared in instrument.lib)
filter = oneZero1(b0,b1)
	with{
			zero = 0.01;
					b0 = 1/(1 + zero);
							b1 = -zero*b0;
								};

process = (*(loopGain) : filter + (envelope*noise*amGain))~delayLine : *(8) : 
	stereo : hgroup("Reverb[3]",component("freeverb.dsp"));

compiling with faust: root@bela:~/Bela/projects/nfaust# time faust sitar.dsp >sitar.h

real 0m2.095s
user 0m0.952s
sys 0m1.000s

making with the IDE: about 2-3 min.

giuliomoro

ok thanks I will have a look

sletz

To speed up JIT compilation, one could imagine to develop a "remote cross-compilation service":

the Bela card would access a distant server (that could be remote or running on the machine running Bela IDE), send the Faust DSP and a description of its architecture (CPU...)
the server does cross compilation that is: Faust DSP ==> LLVM IR ==> machine code, for the requesting machine
send back the machine code on the Bela card
have the Bela card dynamically load the machine code and execute it.

I already tested the path : Faust DSP ==> LLVM IR ==> machine code ==> other machine ==> dynamic load/execute in another context, so in theory it should work also on the Bela card.

We'll probably explore that starting in may.

BTW nice to see the httpUI control working !

DragonSF

I can give you my changed sources (if you want), but it actually wasn't that many changes. Most work was the correct installation of all the libraries involved and find the culprit.

giuliomoro

Sorry I am late to the game.

Did this again and found that the painless way of building HTTPDFaust is to use the provided Makefile in faust/architectures/httpdlib/src/Makefile instead of using the cmake file in faust/architectures/httpdlib/cmake/CMakeLists.txt. The provided Makefile links in the files in hexa/ which provide definitions for jsscripts, jsscripts_len, stylesheet, stylesheet_len. Run with make dynamic and generates a dynamic library faust/architecture/httpdlib/libHTTPDFaust.so.

Reported here https://github.com/grame-cncm/faust/issues/232

sletz

Yes, we have to fix that. Thanks also for your various fixes. I'll try to make the FaustEditor export to bela work again next week.

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