In contrast, SD cards today can handle 22MB per second, and the current controller interface can handle 66MB per second. And manufacturers can ramp up capacities far faster than with optical formats. In addition, obtaining the higher transfer rate with an optical drive requires spinning the disc faster, which results in a noisier mechanism. I bet a camcorder microphone is bound to pick that up. Plus, SD is more durable and easier to work with, especially in the field, and I believe it's cheaper to implement an SD solution than an optical-based one.
But...alas, there's always a but. In conjunction with the SD work, the two companies are also plowing ahead with promoting a recording format that can fit HD on mini DVD discs. AVCHD, which stands for the marriage of the MPEG-4 Advanced Video Coding (a.k.a. H.264) and HD, has a maximum transfer rate of 2.3MB per second. That's not bad. But even though AVC is a high-quality MPEG-4 codec, it's designed to produce a high-quality playback stream from high-quality source material that's passed through complex, iterated, variable-bit-rate compression--not real-time compression from iffy source video.
Furthermore, they're imposing this suboptimal encoding solution on SD-based recording, rather than aiming higher and taking advantage of the format's available bandwidth.
I dunno. Maybe they have some magic algorithms up their sleeves that can produce silk playback out of a sow's video. Or maybe I'm just seen too much bad MPEG-4 and MPEG-2 video come out of camcorders, despite the occasional exception in a higher-end model.
Guess I'll just have to wait and see.