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Re: VariSpeed and Timestamps
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Re: VariSpeed and Timestamps


  • Subject: Re: VariSpeed and Timestamps
  • From: Ethan Funk <email@hidden>
  • Date: Wed, 17 Nov 2004 14:47:16 -0700

Yep, printf-ing the results fixed the skipping. All looks well from the time stamp end of things. I guess I have a mistake else ware in my code. Thanks for helping me understand how VariSpeed works.

Ethan...

On Nov 17, 2004, at 13:56, Doug Wyatt wrote:

On Nov 17, 2004, at 12:43, Ethan Funk wrote:
To check up on the varispeed, I would log the timestamps it pulls you for, e.g.:

pull 1:
	It pulls you at time 1000 for 500 samples.
pull 2:
	is the timestamp 1500? if not, error
	time 1500, 499 samples
pull 3:
	is the timestamp 1999? if not, error

If the timestamps aren't correct, let us know ... if they are, then check your code further ...


I checked the time stamps using break points. The results are as follows:


Pull	sTime (output)	#		sTime  (input)		#
1	37,220,394	1116	16,721,708		512
2	42,873,218	1112	19,318,474		512
3	49,666,285	1116	22,439,039		512
4	55,237,383	1116	24,998,262		512

pulling at 96Ksps, VariSpeed converting to 44.1Ksps on it's input side. This rate conversion appears to be working from the requested sample numbers. The sample times however are all over the place. The delta between pull 1 and 2 on the input side of the VariSpeed is >58 seconds at 44.1Ksps. It took less than 20 seconds for me to write down the numbers and continue execution, so the numbers don't seem to account for that either.

Any ideas?

Don't stop at breakpoints! You'll miss I/O cycles.

Print the numbers. If you want to avoid digging through massive debug spew, just print a message when the timestamp is not contiguous (i.e. currentTimestamp != previousTimestamp + previousPullSize).

Doug


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References: 
 >VariSpeed and Timestamps (From: Ethan Funk <email@hidden>)
 >Re: VariSpeed and Timestamps (From: Doug Wyatt <email@hidden>)
 >Re: VariSpeed and Timestamps (From: Ethan Funk <email@hidden>)
 >Re: VariSpeed and Timestamps (From: Doug Wyatt <email@hidden>)

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