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They know about the issue according to this article,,,,,
M2TechÂs Mac OS X driver for the HiFace introduces a fraction of a second of delay between the source and output, which means that when youÂre watching film or TV video, lipsync will be lost, with voices playing behind the pictures.
The M2Tech HiFace's designer Marco Manunta explained that the Mac driver works differently than the Windows driver: the Mac version doesn't work with fixed-size packets, so a large buffer is needed to avoid 'flux distruption' when several small data packets are sent, instead of one regular size packet.
http://www.pcadvisor.co.uk/reviews/pc-peripheral/3250187/m2tech-hiface-review/.