[Jon Olb]

Hi Guys,
Thanks for your enquiries. The setup is invariably 4 sdi cameras – sometimes a combination of Sony EX cameras and XD Cam. Sometimes 4 identical Panasonics. The cameras always have the same frame-rate etc. What could be causing an issue – though with the in-built synchronisers this should not be an issue – is that sometimes there is video replay from a Macbook Pro. This input is HDMI (from the mini-dvi port), and is always set to the same 50i as everything else. There is no discernable disturbance cutting or mixing from these sources. What happens is that, every so often, there is a visible jump on the output (mid way through a camera shot) where it looks as if a frame is dropped. Then, when it comes time for synching later, there is indeed a synch problem between the switch (however it is recorded) and the ISOs recorded in-camera. The ISOs synch perfectly, but the line cut will drift by several frames, varying each time…