[PD] jack periods 32 = no pd
msp at ucsd.edu
Tue Jan 28 21:24:43 CET 2014
OK... that's really quite strange indeed. FWIW the 'mmap' alsa code, as
far as I know, is only selected for RME devices. I don't have any of those
handy so have little way to check any of this on my end. It was written by
Winfried Ritsch a decade or more ago :)
> Made a latency test with pd's own latency testing patch
> -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 at iem.at mailing list
> > UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
> Pd-list at iem.at mailing list
> UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
More information about the Pd-list