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Re: Host Time epoch

Steve has a case where an audio device's sample time appears to be moving backwards.

I am not aware of any situations where the system's host time goes backwards. More fundamental things than MIDI would probably break if it did.

Doug


On Feb 10, 2005, at 12:21, John Iversen wrote:
Steve,

Sorry, I'm not aware of this issue, but it's of interest to me, and is rather fundamental. Would you mind elaborating? What is the nature of the non-monotonicity--I can't imagine you mean actual reversals in the host time, I hope. Instead, do you mean that the rate of increase of the HostTime is variable, so it drifts away from 'real time'? How large is the effect in your experience?

To take a concrete example: Given that MIDITimeStamps are based on 'HostTime' (right?), are you saying that if midi events are received in at exactly 1 sec intervals the increases in Host time (as seen in the MIDITimeStamp of incoming packets) would not be identical (give or take some small margin of error)? If that's really the case, I don't see how any sequencer could possibly work reliably and not show tempo drift, so I may not be getting the drift of what you're talking about here.

Thanks,

John

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References: 
 >Host Time epoch (From: Geoff Schmidt <email@hidden>)
 >Re: Host Time epoch (From: Jeff Moore <email@hidden>)
 >Re: Host Time epoch (From: Steve Checkoway <email@hidden>)
 >Re: Host Time epoch (From: John Iversen <email@hidden>)



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