Cycling 74 » Topic: Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

david stevens — Sun, 10 Jun 2012 12:05:26 +0000

I have a patch which creates a bunch of temp buffers, copies chunks of a longer buffer into them, saves the temp buffers to hard drive andq then deletes the temps buffers, all using scripting.
(I’m doing it this way because I then load the saved chunks into a kind of sfplay for quick access. (actually, [ibufplayer~])

Everything works fine until I start to delete the buffers. At first it seemed to cause audio to stop, even though dspstatus said it was still on, but with 0% CPU utilisation. I then tried running e delete message thru deferlow. That seemed to work if I deleted one at a time, but wasno good when I automated the process again.
Finally, I tried triggering the deletes 1 at a time, at which point I noticed (in the dsp status window) that the audio was momentarily turning off and on again for every delete. I guess when I ran the process automatically it just wasn’t catching up with itself, with all those audio off/ons.

The question is, is this expected behaviour with max5 (in which case I’ll have to redesign the fragment players), or is something awry, and what might it be?

Thanks

David

Re: Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

mudang — Sun, 10 Jun 2012 13:09:43 +0000

That’s right. Everytime an audio object gets created or deleted, or an audio connection is made, the internal dsp chain gets updated. For this, dsp is momentarily switched off.

Re: Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

mudang — Sun, 10 Jun 2012 13:12:37 +0000

Maybe you can send a “size 0″ to the temp buffers, instead of deleting them…

Re: Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

pid — Sun, 10 Jun 2012 13:52:19 +0000

this is the way MSP has always worked, from 1997 – 2011. all softwares like this work in this way, e.g. Pd.

in Max6 you can do this successfully using the Mixer Crossfade settings.

however scripting deletion of buffer~s is a bit crazy and there are surely better ways around you problem. you might find polybuffer~ to your liking too (also Max6). if the buffers are small there will be no significant ram gain in deleting them.

if you decide you really need to ‘delete’, why not put them all in a poly~ and mute it when done instead?

Re: Why does deleting a buffer cause audio to switch off & on? (max5) (bit urgent!)

david stevens — Sun, 10 Jun 2012 14:23:32 +0000

Thanks for the suggestions –

This is the first time I’ve attempted doing this, which is why I didn’t come across the issue before.
The reason I wanted to delete the buffers is that they are only used to get the cut up audio onto the hard drive. And there may be several tens of users during the course of any day, which is why I wanted to delete them after use.

In the end (as I’m sticking with max5 for this project)’, I’ve decided to use precreated buffers, write to them from the slicing object, and play from them using groove~ with set $1 messages . It seems to work just as well.