Am Sonntag, Dezember 02, 2018 10:17 CET, Alexandre Ratchov <a...@caoua.org> schrieb:
> On Sat, Dec 01, 2018 at 01:19:00PM -0600, Adam Thompson wrote: > > PROBLEM STATEMENT: driving FluidSynth from a MIDI controller produces > > ~1/4sec delay between keypress and sound. > > > [...] > > > Is sndio(4) suitable for real-time(-ish) performance? Or do I need > > a (OS) platform that does ASIO or JACK? (I mostly play by ear so > > I'm targeting <<0.1sec latency.) > > Yes, sndiod is usable (actually designed for) low-latency usage. You > need to change the sndiod buffer size to whatever your system can > handle (depends on CPU, audio interface). I'd recommend to set in > /etc/rc.conf.local > > sndiod_flags=-z240 > > Let us know how it works. If it works, you could try -z120, that's > what I use on my machines. -z120 is a bit too much for my box, but -z240 does the trick for me. Thanks, Sebastian > > -z240 sets the block size to 240 samples, at 48000Hz sample frequency, > this corresponds to 48000Hz / 240 = 5ms block. The total end-to-end > latency is typically 3 blocks, so I'd get 5ms * 3 = 15ms. > > FWIW, for music, you shouldn't exceed few tenths of ms of latency. > > > > > Dmesg follows, just in case anyone spots anything useful in there… > > > > Hardware setup, broadly: > > * Dell Latitude E6430 laptop > > - booting in EFI mode to work around a weird bootloader bug > > * onboard azalia(4) audio (for now) using onboard speakers (for now) > > * Roland A500PRO MIDI controller, connected via USB > > * M-audio Uno USB-MIDI, nothing connected to it yet > > * No-name USB 5.1ch Audio DAC from Amazon, nothing connected to it yet > > - (leaving the M-audio umidi and the "ABC" uaudio devices disconnected > > makes no difference) > > > > The "ABC" USB devices are unlikely to work with small blocks, but > there are fixes comming soon (hopefully). >
