* Peter P. <p8...@aol.com> [2014-01-28 00:35]: > * Miller Puckette <m...@ucsd.edu> [2014-01-28 00:02]: > > Probably that's so - but Pd should still be able to deal with the mismatch. > > OTOH, since Pd is built-in 64 blocksize, you wouldn't be able to reduce Pd's > > latency by reducing jack's blocksize below 64. > Allright, then I can live without going lower. > > > I'm not sure about this, but I believe that Pd running standalone (using > > ALSA > > driver) can achieve as low or perhaps slightly lower latency than Pd running > > under jack. This is only of interest if Pd's the only audio application > > you're running on that particular audio interface, however. > I can currently start pd using > -alsa -rt -audiobuf 2 > and get click-free performance, as long as I don't the classic "Select > all.." and move things around in Tcl/Tk, which of course causes > drop-outs. Haven't measured latency with that setup yet, but it sure > sounds promising. Using the oss emulation of alsa works too, but > slightly more clicks when moving objects on the canvas.
Made a latency test with pd's own latency testing patch /usr/local/lib/pd/doc/7.stuff/tools/latency.pd -alsa -rt -audiobuf 2 -channels 18 on an HDSPe card with Multiface and a loopback analogue cable gives 6.5ms, which I consider great! Interestingly Pd gives this latency value regardless of setting -audiobuf to values 1-6, which I suppose is because of rounding this value to something usable by the dsp part. Pd also reports on startup "...buffer_time 2902 us opened" "using mmap audio interface" Now what is weird, is that I can't get clean audio under alsa with any values larger than -audiobuf 6. The sound is very distorted. Using the -oss emulation and -rt, clean audio is available for values larger than -audiobuf 2 such as: -audiobuf 3 with measured latency of 7.9ms (Pd choses blocksze 56) -audiobuf 5 with measured latency of 9.4ms (Pd choses blocksze 56) -audiobuf 6 with measured latency of 10.9ms (Pd choses blocksze 56) and so on. Oh this is on a Debian system running kernel 3.2.0-4-rt-amd64 Nice that Pd can do so low latencies, but that's a strange thing about alsa though... > > best, P > > _______________________________________________ > Pd-list@iem.at mailing list > UNSUBSCRIBE and account-management -> > http://lists.puredata.info/listinfo/pd-list _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list