Even though you don't have audio coming out when you're muting, you're still doing dsp. You should put each channel in a sub patch or abstraction and use [switch~] to enable/disable that abstraction. This is super important with low resource machines. The best fix is to do a quick (10-5ms) fade in/out when muting/unmuting, then hit [switch~] so you don't get any clicks:
On May 5, 2013, at 12:12 PM, pd-list-request@iem.at wrote:
From: Halfdan Mouritzen halfdan@robothangarskib.dk Subject: [PD] High CPU usage when tracks are muted (Raspberry Pi) Date: May 5, 2013 12:11:56 PM EDT To: pd-list pd-list@iem.at
Dear PD Friends,
We are building a collaborative music sculpture, using five Raspberry Pi's to each run a seperate instrument / HID. Everything is very well, they each run a minimal Arch installation and boot up into PD without a GUI.
One machine we are building at the moment, is just a very basic sample player - it has 8 tables with samples, that get played via a looping tabplay~. The machine works by simply muting and unmuting of the different channels - very basic.
Now the problem is that when all eight tracks are unmuted the CPU usage is around 15-16 % - very fine, with lots of room for other activities. NOW, when one mutes channels, the CPU usage starts climbing and climbing, resulting in 95-100% usage when all the channels are muted... This results in lagging/glitching, when one tries to turn on channels again. The muting / unmuting is done through a simple *~ which gets set to either 0 or 1 with a line.
I have noticed others have experienced this problem, but I haven't been able to find a solution to the problem. Hope somebody has a solution, as we are installing the machine at a music festival this week, and plan to open source all patches/sounds/build plans etc.
All the best and keep on patching Halfdan & Jonathan
Dan Wilcox @danomatika danomatika.com robotcowboy.com
