Hi, On Saturday 28 March 2009 16:39:35 Ken Restivo wrote: > When a LADSPA plugin is being sent zeroes-- i.e. when the volume of the > input data is down to nothing-- is it still sucking up CPU cycles? > I understand from the JACK API that anytime a client gets a callback with > data, it has to drop down and deal with the data and then return, even if > the data is zero. But that could be lightweight, if the data are zero, or > is that very compute-intensive for the plugin? > I'm trying to build an outboard effects chain in various LADSPA hosts (JACK > Rack, ecasound, AMS, others... haven't settled on one yet), and when I've > got that plugin's volume MIDI'ed down to zero, I'd like it to not be > dominating CPU cycles at that time. Actually with double- (or any floating point-) resolution it is rather hard to detect exact 0.0 values. And because of the variable exponent, the cpu usage for numbers near zero is higher then for numbers near 1 (or any other higher value). The keywords to search for are "denormal problems". In practice this means that while setting a volume to zero "should" give you the desired effect of less cpu-usage, in fact the opposite is the case in the worst case. When you are already controlling your effects via midi, why not bind the "mute" or "active" (don't remember the current naming in jack-rack) to a midi controller. An in-active effect shouldn't eat cpu cycles when the host-author did his job right... Have fun, Arnold
Attachment:
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
