[linux-audio-user] SBLive capture period limit?

Paul Perkins speaker-to-vegetables at pobox.com
Wed Apr 23 20:02:01 EDT 2003


I've looked for a Fine Manual on this but no luck:
Jack starts OK with a period size of 512 but with 256 or 128 it seems to
say that the ALSA driver refuses to accept it. Does anyone know, is this
a hardware limitation of the card, or something I can change with a
magic parameter in some configuration file? The card is an old SBLive
Value (the box said something about MP3) and the software is Red Hat 8 /
Planet CCRMA / emu10k1.

If I have understood the Jack documentation correctly, this corresponds
to about a 35 millisecond buffering delay for the round trip of a signal
from the outside world into the computer and back out again. Plus any
time spent processing the signal inside the computer. Not bad, really, I
guess. I wonder what an M-Audio Delta could do?

jackstart -R -d alsa -d hw:0 -p 256 -n 2 -r 44100
jackd 0.67.2
Copyright 2001-2003 Paul Davis and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details

loading driver ..
driver client name = [alsa_pcm]
creating alsa driver ... hw:0|256|2|44100|swmon|swmeter|rt
open
ALSA: cannot set period size to 256 frames for capture
ALSA: cannot configure capture channel
starting engine
engine driver not set; cannot start
cannot start main JACK thread
jack main caught signal 15

-- 
sigmotto: Liberty is theft.




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