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.