2017-06-02 14:12 GMT+02:00 Theo Verelst <theo...@theover.org>: > While designing and testing an automatically created filter/multi-compressor > bank of 30 "jack-rack" holders of (Linux) Ladspa DSP elements, I was > reminded of > something I've noticed before. Some audio effects use a lot of CPU resources > when > idle, or in other words when no signal input is present. > > The way I work is having Jack run it's standard 32 bit floating point audio, > and having a lot of these racks suddenly use half a thread processor of the > CPU a piece has two negative side effects: the CPU gets hot (when the clock > is maxed out even too hot), and there are X-Runs (audio processing graph run > failures) which, even when signal returns, take a while to disappear before > normal processing resumes. > > I tested one solution of this problem, there's another: check out the (Open) > Source code and fix the problem, namely: inject the signal graph with a > -160dB tiny noise signal, which prevents it from going into overload mode. > So I made another jack-rack with a noise generator, adjusted it to -80dB, > limited the signal and attenuated another 80dB so that no signal processing > I work with has serious trouble with the added noise. This appears to work: > the processor load remains constant in the absence of signal.
This looks denormals-realted. If that's the case, a better option would be to set processor flags for flushing-to-zero denormals in the host or, even better, in the plugins (FTZ and DAZ flags for x86/x86-64). Sometimes recompiling with proper compiler flags is sufficient (e.g., -ffast-math in case of GCC). _______________________________________________ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
