[linux-audio-user] Developers: how to sync PCM to Midi?

[Denis de Leeuw Duarte]

Hello folks,

I'm writing a realtime audio tool and I'd like to pick your brains on the 
following: say my app is rendering some sound and a midi event comes in, at 
what point in time should the resulting effect occur in the rendered audio 
stream?

The obvious solution would be to measure world/system time at the moment 
playback is started in my application. If a midi event then comes in, I can 
subtract this start time from the midi event time. I am however afraid that 
my timing will then drift each time an underrun occurs. I'm pretty sure 
applications like terminatorx, sweep and a host of others solved this 
problem before me so if anybody knows the answer to this, please let me 
know!

Regards,

Denis

p.s. I use JACK for audio output but the solution really should be 
independent of this.

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www.cyozlab.com

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