davidm Posted July 14, 2010 Report Share Posted July 14, 2010 Tested the timecode stability a software timecode generator on an iPod Touch 3G. Downloaded Pocket Sync, a timecoode generator app from France: http://www.polytonic.fr/ Set Pocket Sync to 25fps / 48KHz. Jammed a GPS calibrated Ambient Master Controller to the Pocket Sync signal via the headphone jack. Drift was approx +0.9 frame per hour. Set Pocket Sync to 30fps / 48KHz. Drift was approx +1.2 frame per hour. Set Pocket Sync to 24fps / 44.1KHz. Drift was approx +0.6 frame per minute! Pocket Sync 29.97 shows up as 30fps drop. Perhaps there are math division errors in dividing the sample clock by the timecode rate. Conclusion: Not good enough. David M Auckland NZ Quote Link to comment Share on other sites More sharing options...
studiomprd Posted July 14, 2010 Report Share Posted July 14, 2010 " Perhaps there are math division errors " perhaps there are time base (crystal) stability issues! (much more likely) Quote Link to comment Share on other sites More sharing options...
davidm Posted July 15, 2010 Author Report Share Posted July 15, 2010 " Perhaps there are math division errors " perhaps there are time base (crystal) stability issues! (much more likely) The odd thing about this software is that the user gets to choose the sample rate. As the drift is far worse at 44.1KHz than 48KHz, I'm sticking with the math error theory although the crystal stability is always going to be suspect in a consumer device. I'm guessing the timecode slate apps on the iPod / iPhone will have similar problems. David M Auckland, NZ Quote Link to comment Share on other sites More sharing options...
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