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jit.gl.hap stutter

March 26, 2014 | 10:21 am

I’ve converted over to the wonderful jit.gl.hap object for all video playback (thank you Rob!) but have noticed an issue with any changes to the @rate attribute. The video stutters momentarily, making it impossible to do smooth rate ramps.

I’ve noticed this same stuttering behavior when a HAP movie loops.

This is on a Mac Pro, Mountain Lion, Max 6.16, latest version of HAP codecs and jit.gl.hap. The HAP files are being played back from a RAID 10 striped array, with the files limited to 10MB/sec data rate.

The stuttering happens consistently, regardless of how many HAP files are being played back at once.

Any thoughts?


March 26, 2014 | 2:37 pm

unfortunately this is a problem with the quicktime player.
if you need smooth rate changes, it’s probably best to set the rate to 0 and create your own timing mechanism using the frame or time message.


March 26, 2014 | 3:24 pm

I see – that’s certainly doable, although I have not seen the issue with the jit.qt.player object.

Is this behavior also expected upon loop as I’ve been observing?


March 27, 2014 | 11:20 am

maybe?
i’m guessing this is the result of using qtkit instead of raw quicktime.
i’ll make an issue to look at getting rid of qtkit.

https://github.com/robtherich/jit.gl.hap/issues/13


March 28, 2014 | 9:01 am

Thank you Rob – your efforts on this are much appreciated.


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