Jamin and CPU

Hi guys,
This is not really ardour related.

I use jamin 0.97.09, this is a great tool. But, as soon as I fire it after jack is started, it takes up 25% CPU. Why ? Nothing happens, jack is at rest, nothing is processed through jamin. There’s no apparent reason why jamin should eat up so much by doing nothing.

Can anyone enlighten me on this ?
Thanks.

Same situation here…I’m wondering if it doesn’t wait to sense audio input to apply the compression and eq, ie it’s always on regardless of the signal.

Same situation here…I’m wondering if it doesn’t wait to sense audio input to apply the compression and eq, ie it’s always on regardless of the signal.

Nothing happens, jack is at rest, nothing is processed through jamin. There’s no apparent reason why jamin should eat up so much by doing nothing.

Not true. Jamin is always processing no matter what. It processes whatever audio streams are sent to it, including streams of 0’s. (i.e. when nothing is connected)

IIRC is is also processing when you hit any of the bypass buttons so that you can do A/B comparisons without any delay offsets when toggling.

I don’t know the internals of jamin so please, put up with my ignorance. This sounds to me like a waste of power, really. Why should it process 0’s ? I personnaly don’t really care about delays, they cannot be that big (what are we talking about ? 1sec, 10sec, 10msec ?). Does that justify all this wasted CPU power ? Think about it : 25% of one core of my Core 2 Duo CPU, that’s a lot. So when I leave the DAW for some time, all it does is heating itself for nothing. Sure I could close jamin but this is the kind of thing that gets annoying in a daily routine. Or maybe it has something to do with JACK ? if jamin took too much time to get going, jack would kick it out of the graph ? Is it more something like that ?

This is the way all plugins work, and incidentally, all audio hardware. Silence is still audio. The only plugin that I know of that would treat silence differently is a gate or similar dynamics-related plugin, and even then it is still using the same amount of resources.

If you wish Jamin was more efficient in general, that would be a different issue… though I will venture to guess that conserving DSP power is one of the developers’ goals. Simply stated, multiband compression and equalization are not “cheap” computationally.

It’s not like an audio editor where you are working with a file. When you want to apply a plugin it does all the work and then it’s done.

Anything Jack related is working with streams, not files. Streams have no start and no end, so Jamin is getting a stream of audio from it’s input ring buffer, even when there is nothing dumping data into that ring buffer.

All other Jack apps do this too. It’s just that most of them don’t do near as much processing as Jamin, so you probably don’t notice the overhead.