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

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. --------------- www.cyozlab.com _________________________________________________________________ MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*. http://join.msn.com/?page=features/virus