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Neurobs Presentation

454 bytes added, 11:08, 26 November 2015
Screen synchronization issue on 120 Hz screens
== Screen synchronization issue on 120 Hz screens ==
There is a serious synchronisation issue where the picture.present() method returns one frame too early. It can be detected by measuring the time between two consecutive present() calls returning:
 <codepre>wait_interval(220)
picture1.present()
int t0 = clock.time();
int t1 = clock.time();
int dt = t1-t0;
</codepreOne would expect ''picture1'' to be shown for 1 frame (1/120 s) and time ''dt'' to show this. Sometimes this is not the case. The image will be shown for one frame (1/120 s), but ''dt'' will be 2/120 s: [[File:Timeline.svg|none|thumbnail]] The fact that ''picture1'' is shown for only 1/120 s was confirmed with a light sensor connected to an oscilloscope. The chance of this issue occurring is highly dependant on the waiting time

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