[Linuxsampler-devel] voice stealing

[Vladimir S. <ha...@so...>]

Hi Everybody,

I've been thinking about note stealing or as i'd like to call it "voice 
stealing".
So far the following comes to mind:
1) When number of voices reaches max there will not be any time to 
release them, so we have to start releasing them earlier. I'm 
introducing AUDIO_VOICES_THRESHOLD. It should be set to be a certain 
percentage of MAX_AUDIO_VOICES depending on how long the release phase 
is. If it's set to the same value as MAX_AUDIO_VOICES or higher, then 
voice stealing will be disabled.
2) When number of voices reaches the threshold and a new key is pressed, 
ls will try the following:
 a) locate voices on that same key and release all but the last one of them
 b) if that didn't yeld any results, go thru all keys and try same
 c) if that didn't work either, try same as above but be more aggressive 
i.e. free the last voice as well.

What do you guys think? Any better ideas?
I've been playing around with it and it seems to work OK. With max 
voices set to 64 i've set the threshold to 48 and it seems to take care 
of most situations. Depending on how long the release phase is, it may 
need to be set to something lower (or max voices will have to be 
increased). At some point we could add a clever algorithm to calculate 
the threshold automatically based on how long the release phase is 
(average release time for all samples?)

I'm including a patch against latest CVS. This patch also includes some 
command line and EG changes. Christian will likely review those (but not 
the voice stealing part) next weekend and it might make it in some shape 
of form into the CVS, so please give it some testing also, if you have 
time. If you have trouble with voice stealing and just want to play 
around with the EG you can turn off voice stealing by setting 
AUDIO_VOICES_THRESHOLD to be same as MAX_AUDIO_VOICES in audiothread.h.

Regards,
Vladimir.