Re: stereo mixer (not synth) / music device bug?
Re: stereo mixer (not synth) / music device bug?
- Subject: Re: stereo mixer (not synth) / music device bug?
- From: Chris Rogers <email@hidden>
- Date: Sun, 15 Dec 2002 13:51:05 -0800
Chris,
It sounds like your problem is simply that you're overloading the
CPU when you have three or more MusicDevices running at the same
time. It turns out that the DLSMusicDevice has the option of
either using its own internal reverb, or sending out a reverb
send (for use with external reverb) on a secondary bus.
By default the synth uses the internal reverb, but in your application
you can share a single reverb among all of your DLSMusicDevices
through the use of the kMusicDeviceProperty_UsesInternalReverb
property (set it to false). Then you'll need to create a second
stereo mixer to mix the reverb send from each MusicDevice.
By sharing a single reverb, you avoid running multiple reverbs which
can be quite expensive...
The outputs of the DLSMusicDevice change according to the
kMusicDeviceProperty_UsesInternalReverb property:
Configuration using reverb send
-------------------------------------------
property value = 0, output bus 0 is the reverb send, bus 1 is the
main synth output
Default configuration using internal reverb
-------------------------------------------
property value = 1, output bus 0 is the main synth output (with reverb
already mixed in)
The AUGraph becomes somewhat more complicated since there's a second
stereo mixer, etc., but there's a considerable gain in efficiency
which should let you have many MusicDevices, as long as all together
they're not playing a large number of notes!
Hope this helps,
Chris Rogers
Core Audio
Apple Computer
>
Just a correction to the previous post's title, it's the stereo mixer,
>
with multiple DLS synths, that causes this bug.
>
>
Thanks again for any suggestions or confirmations of the problem...
>
Chris
>
>
[....]
>
>The misbehavior is, if I add more than three MusicDevices, everything
>
>gets 'strange'. The app begins responding sluggishly, playing of instrument
>
>sounds is mangled (it sounds like sounds are being rendered at a
>
>much lower frequency), and eventually the app can hang. However
>
>if I limit myself to three MusicDevices everything works perfectly including
>
>mixing through the mixer unit. If I create the graph with four
>
>music devices,
>
>the problem is there, and if I then remove one at runtime and
>
>update the graph the
>
>problem goes away and things return to normal.
>
_______________________________________________
>
coreaudio-api mailing list | email@hidden
>
Help/Unsubscribe/Archives:
>
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
>
Do not post admin requests to the list. They will be ignored.
_______________________________________________
coreaudio-api mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/coreaudio-api
Do not post admin requests to the list. They will be ignored.